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  • Active loading graphite/hydroxyapatite into the stable hydroxyethyl cellulose scaffold nanofibers for artificial cornea application
    Cellulose (IF 3.917) Pub Date : 2020-01-25
    Davood Kharaghani, Debarun Dutta, Kitty K. K. Ho, Ke-Qin Zhang, Wei Kai, Xuehong Ren, Mark D. P. Willcox, Ick Soo Kim

    Abstract The design of biocompatible porous scaffolds that encourage cell adhesion for corneal tissue engineering applications continues to be challenging. In addition to porous hydrogels, nanofibers that can simulate the extracellular matrix structure for cell adhesion would be beneficial. Graphite and nano-hydroxyapatite (nHA) are two bioactive materials that have been used to improve cell adhesion in scaffolds for corneal tissue engineering. In this study, nanofibers were fabricated from hydroxyethyl cellulose and polyvinyl alcohol (PVA) and cross-linked by glutaraldehyde bound to graphite and nano-hydroxyapatite. This scaffold surrounded a transparent hydrogel core from PVA that was cross-linked by freeze-thawing cycles. The chemical and mechanical evaluations demonstrated that nanofibers met the requirements as a scaffold for corneal tissue engineering. The results showed that when the concentration of nHA was approximately 1.66 wt%, the morphology of human epithelial cells did not change, and clot formation occurred around the scaffold during the 1-week in vivo implantation. Graphic Abstract

    更新日期:2020-01-26
  • Oxidized bacterial cellulose membrane as support for enzyme immobilization: properties and morphological features
    Cellulose (IF 3.917) Pub Date : 2020-01-25
    Niédja Fittipaldi Vasconcelos, Fábia Karine Andrade, Lídia de Araújo Pinto Vieira, Rodrigo Silveira Vieira, Juliana Miguel Vaz, Pascale Chevallier, Diego Mantovani, Maria de Fátima Borges, Morsyleide de Freitas Rosa

    Abstract Bacterial cellulose (BC) membrane can be architected to covalently immobilize biomolecules, generating materials with new functionality. The processes of purification (via alkaline treatment) and chemical modification (via NaIO4) to the wet BC membrane is the innovation of this work. This wet oxidized BC (OxBC) membrane could act as a support matrix for covalent immobilization of enzymes. BC produced over 5 days of static fermentation, followed by purification with K2CO3 (BC-5d-K2CO3) was selected for our study due to high porosity and surface area, which are properties that favor its chemical modification. This wet BC membrane proven suitable for NaIO4 oxidation. Time and temperature conditions were evaluated in the oxidation reaction, with oxidation BC (OxBC) performed at 1% (w/v) NaIO4 for 6 h at 55 °C under most advantageous conditions, as it provided 50% oxidation degree and preserved its morphological structure. BC and OxBC were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Scanning electron microscopy, mechanical test, and thermal analysis. The oxidation reaction decreased BC crystallinity, tensile strength, and thermal stability and compacted the cellulose layers. BC and OxBC showed non-cytotoxicity. Fourier transform infrared confirmed that OxBC can covalently immobilize papain and that after immobilization the enzyme showed a recovered enzymatic activity of 93.1%. In addition, the oxidized membrane presented greater amount of immobilized papain in its study than BC, proving to be a more efficient support for enzymatic immobilization. Graphic abstract

    更新日期:2020-01-26
  • Superhydrophobic, flame-retardant and conductive cotton fabrics via layer-by-layer assembly of carbon nanotubes for flexible sensing electronics
    Cellulose (IF 3.917) Pub Date : 2020-01-24
    Chao-Hua Xue, Yue Wu, Xiao-Jing Guo, Bing-Ying Liu, Hui-Di Wang, Shun-Tian Jia

    Abstract Functional textiles are ideal substrates for wearable electronics. Herein, superhydrophobic, flame-retardant and conductive cotton fabrics were fabricated by sequential assembly of poly(ethylenimine), ammonium polyphosphate and carbon nanotubes, followed by post-treatment with poly(dimethylsiloxane). The resulting fabrics possessed excellent superhydrophobic stability toward acid, alkali, organic solvent, UV irradiation, abrasion and long-time laundering. Meanwhile, when suffering to fire, the coated fabric could generate an efficient char layer and extinguish the fire to protect the cotton fiber from forming flame. Furthermore, this conductive cotton fabric exhibited stable sensing ability in contact with water droplets, showing wide potential application in wearable electronics as multifunctional smart textiles.

    更新日期:2020-01-26
  • Applications and impact of nanocellulose based adsorbents
    Cellulose (IF 3.917) Pub Date : 2020-01-24
    Kazım Köse, Miran Mavlan, Jeffrey P. Youngblood

    Abstract Efficient separation and removal is necessary in applications ranging from environmental remediation to the food sector. A well-designed adsorption system should meet the demands for high efficiency in a cost and time effective manner. In wastewater treatment, the ideal chemical feedstock used to synthesize the adsorbents should themselves been environmentally friendly (i.e. non-toxic) to avoid subsequent environmental issues. Nanocellulose, made of the most abundant organic biopolymer on earth, fulfills many criteria to fit the profile of a highly safe, but efficient adsorbent. A survey of the literature reveals that nanocellulose materials have a proven track record as viable alternatives as adsorbents. To summarize these recent advances, this review describes the methodologies under current use for such designs and gives a systematic overview of these technologies to promote a more focused research in the future for nanocellulose based adsorbent materials.

    更新日期:2020-01-24
  • Homogeneous preparation of aerocellulose grafted acrylamide and its CO 2 adsorption properties
    Cellulose (IF 3.917) Pub Date : 2020-01-24
    You Tang, Shengwei Tang, Tao Zhang

    Abstract Aerocellulose with three-dimensional pore structure and amino groups was prepared by free radical grafting polymerization of acrylamide based on the homogeneous ionic liquid system. The effects of reaction temperature, reaction time, initiator dosage, monomer dosage and crosslinking agent dosage on the loading ratio were studied. The aerocellulose was characterized by Fourier transform infrared spectroscopy, elemental analysis, X ray diffraction, scanning electron microscope, thermogravimetric analysis and N2 adsorption–desorption analysis. The adsorption capacity of CO2 was measured on a static adsorption device and the results indicated that adding N, N-methylene-bis-acrylamide (MBA) as a cross-linking agent could increase the loading ratio significantly. The loading ratio could reach up to 38.59% when reaction temperature is 333.15 K, reaction time is 6 h and cellulose:APS:AM:MBA = 1:0.1:6:0.1. Although the specific surface area decreased after grafting process, the CO2 adsorption capacity achieved 1.07 mmol/g at 315.15 K and 190 kPa, while the adsorption amount of ungrafted aerocellulose was only 0.52 mmol/g. Furthermore, the fitting results showed that the CO2 adsorption behavior on ungrafted aerocellulose belongs to physical adsorption process, and the adsorption on grafted aerocellulose belongs to both physical and chemical adsorption process.

    更新日期:2020-01-24
  • Hydrophobic modification of bacterial cellulose using oxygen plasma treatment and chemical vapor deposition
    Cellulose (IF 3.917) Pub Date : 2020-01-24
    Salomé Leal, Cecília Cristelo, Sara Silvestre, Elvira Fortunato, Aureliana Sousa, Anabela Alves, D. M. Correia, S. Lanceros-Mendez, Miguel Gama

    Abstract A new strategy for the surface modification of bacterial cellulose (BC) through the combination of oxygen plasma deposition and silanization with trichloromethyl silane (TCMS) is described. The combined use of the two techniques modifies both the surface roughness and energy and therefore maximizes the obtained hydrophobic effect. These modified membranes were characterized by Scanning Electron Microscopy (SEM), water contact angle measurements, Fourier-transform infrared spectroscopy (FTIR-ATR) and X-ray photoelectron spectroscopy (XPS), and its cytotoxic potential was investigated using both indirect and direct contact in vitro studies. The obtained results suggest an effective conjugation of TCMS to the surface of BC, leading to a highly hydrophobic surface, with a water contact angle of approximately 130º. It is also demonstrated that this is a stable and durable surface modification strategy, since BC remained hydrophobic even after 6 months, in dry conditions or after being submerged in distilled water for about a month. Importantly, this surface modification revealed no short-term cytotoxic effects on L929 and hDNFs cells. Altogether, these data indicate the successful development of a surface modification method that can be applied to BC, enabling the production of a biodegradable and hydrophobic platform that can be applied to different areas of research and industry. Graphic abstract

    更新日期:2020-01-24
  • One-pot synthesis of HMF from carbohydrates over acid-base bi-functional carbonaceous catalyst supported on halloysite nanotubes
    Cellulose (IF 3.917) Pub Date : 2020-01-24
    Yunlei Zhang, Bing Li, Wen Guan, Yanan Wei, Changhao Yan, Minjia Meng, Jianming Pan, Yongsheng Yan

    Abstract Nitrogen-doped carbon materials have attracted enormous interest in catalysis owing to their outstanding catalytic performance. In this work, nitrogen-doped carbonaceous catalysts (NCC) supported on inexpensive and naturally abundant halloysite nanotubes were successfully synthesized via precipitation polymerization, calcination, and sulfonation processes. The physical and chemical properties of the obtained catalysts were systematically characterized by different methods. The results indicated that NCC catalysts had mesoporous structures, excellent thermostability and acid-base bi-functional active sites. One-pot synthesis of 5-hydroxymethylfurfural (HMF) from glucose was performed to investigate the synthesized NCC catalysts. Benefiting from the synergistic effects of the acid-base bi-functional active sites, the highest HMF yield (62.8%) was achieved in an isopropanol-mediated DMSO system under optimal conditions. Moderate to excellent yields of HMF were also obtained from one-pot conversions of other carbohydrates, including inulin, sucrose, cellobiose, maltose and starch, with our developed catalytic system. The one-pot production of HMF from cellulose was also smoothly processed by the NCC bi-functional catalyst in an IL-based system. This work has developed a versatile strategy for designing nitrogen-doped carbonaceous catalysts that can be employed for the direct transformation of renewable carbohydrates to platform chemicals.

    更新日期:2020-01-24
  • Super-magnetization of pectin from orange-peel biomass for sulfamethoxazole adsorption
    Cellulose (IF 3.917) Pub Date : 2020-01-23
    Avinash A. Kadam, Bharat Sharma, Ganesh Dattatraya Saratale, Rijuta Ganesh Saratale, Gajanan S. Ghodake, Bhupendra M. Mistry, Surendra K. Shinde, Seung Cheol Jee, Jung-Suk Sung

    Abstract In recent decades, the release of emerging pharmaceutical contaminants has been recognized as a challenging environmental issue. This study focuses on the adsorption of sulfamethoxazole (SMX) by pectin (Pec)-based bio-adsorbent. Pec was extracted from orange peel-waste biomass (OPB) by a microwave-assisted extraction method. Further, different concentrations of Pec from OPB (Pec-OPB); 0.5, 1, 2 and 4g were super-magnetized with Fe3O4 nanoparticles (denoted as Fe3O4@Pec-OPB(0.5g), Fe3O4@Pec-OPB(1g), Fe3O4@Pec-OPB(2g) and Fe3O4@Pec-OPB(4g), respectively). Among these synthesized bio-adsorbents, Fe3O4@Pec-OPB(1g) gave significant SMX adsorption and hence studied further in detail. Surface-morphology, structure, functional-groups, magnetic-property, and elemental-composition of facile of Fe3O4@Pec-OPB(1g) was characterized by standard analytical techniques. Different parameters for SMX adsorption on Fe3O4@Pec-OPB(1g) were investigated, such as optimal pH (4.0), kinetics (best-fitted pseudo-second-order kinetic model) and isotherm models (best-fitted Redlich-Peterson model). The maximum adsorption capacity (qm) of Fe3O4@Pec-OPB(1g) was 120 mg g−1 of SMX. Thermodynamic analysis corroborated the endothermic nature of the adsorption process. Therefore, the nano-bio-adsorbent Fe3O4@Pec-OPB(1g) exhibits excellent potential for capturing the SMX from water, suggesting that Fe3O4@Pec-OPB(1g) could be a viable option for adsorptive reclamation of hazardous cationic pollutants from water. Graphic abstract

    更新日期:2020-01-23
  • Dispersion of quinacridone pigments using cellulose nanofibers promoted by CH–π interactions and hydrogen bonds
    Cellulose (IF 3.917) Pub Date : 2020-01-23
    Yasuko Saito, Shinichiro Iwamoto, Naoya Hontama, Yuki Tanaka, Takashi Endo

    Abstract Organic pigments are prone to aggregate, resulting in decreasing of their properties. Therefore, pigment dispersants are demanded to have both high adsorption capacity and aggregation inhibiting property for pigment particles. In the present study, the suitability of cellulose nanofibers (CNFs) as a dispersant for quinacridone, a common red–violet organic pigment, was investigated. Quinacridone particles were well adsorbed on the CNFs. Scanning electron microscopy images of the quinacridone–CNF mixtures showed that the quinacridone primary particles were stacked along the cellulose fibers, and the aggregations were inhibited. In addition, the size of the quinacridone particles had an effect on their color. The interactions of quinacridone and cellulose were investigated by Fourier transform infrared (FTIR) and solution-state nuclear magnetic resonance (NMR) spectroscopies. FTIR spectra of the quinacridone–CNF mixtures indicated the intermolecular interactions between quinacridone and cellulose. Because quinacridone and CNFs were insoluble in the NMR solvents, gel-state NMR spectroscopy, which has been used for the whole plant cell wall analysis, was conducted on them. Consequently, whole signals arising from quinacridone and cellulose were enabled to be assigned, and the coupling constant of quinacridone has reported for the first time. The nuclear Overhauser effect spectroscopy (NOESY)-NMR spectrum of the quinacridone–CNF mixture revealed both NH group and aromatic moiety of quinacridone were interacted with glucose unit. The former was considered to be related to hydrogen bonding, and the latter to CH–π interactions. These specific interactions might contribute to achieve the high adsorption capacity of CNFs for quinacridone. Graphic abstract

    更新日期:2020-01-23
  • Multi-scale structural analysis of xyloglucan colloidal dispersions and hydro-alcoholic gels
    Cellulose (IF 3.917) Pub Date : 2020-01-23
    Clelia Dispenza, Simona Todaro, Maria Antonietta Sabatino, Delia Chillura Martino, Vincenzo Martorana, Pier Luigi San Biagio, Paola Maffei, Donatella Bulone

    Abstract Xyloglucans are highly branched, hydroxyl rich polyglucans that for their abundance in nature, biocompatibility, film forming and gelation ability may take a prominent role in the design and fabrication of biomedical devices, including in situ forming scaffolds for tissue engineering, wound dressings and epidermal sensors. The understanding and exploitation of their self-assembly behavior is key for the device performance optimization. A multi-scale analysis, conducted combining small-angle X-ray scattering, both static and dynamic light scattering at large and small angles, and rheological measurements, provides a description of the supramolecular organization of this biopolymer, from the scale of a few nano-meter, to the meso- and macro-scale both in the sol and gel states. Xyloglucan self-assembly is described as multi-step and hierarchical process with different levels of organization.

    更新日期:2020-01-23
  • Correction to: Fabrication of SiO 2 –ZnO NP/ZnO NR hybrid coated cotton fabrics: the effect of ZnO NR growth time on structural and UV protection characteristics
    Cellulose (IF 3.917) Pub Date : 2020-01-22
    Merve Küçük, Mustafa Lütfi Öveçoğlu

    In the original published article, the figure 4f was wrongly processed with the same part of figure 5f.

    更新日期:2020-01-23
  • Facile fabrication of carboxymethyl chitosan/paraffin coated carboxymethylated cotton fabric with asymmetric wettability for hemostatic wound dressing
    Cellulose (IF 3.917) Pub Date : 2020-01-22
    Yamei Wang, Dongdong Xiao, Yi Zhong, Linping Zhang, Zhize Chen, Xiaofeng Sui, Bijia Wang, Xueling Feng, Hong Xu, Zhiping Mao

    Abstract Achieving effective hemostasis is significant to ensure the survival of the people with acute massive bleeding in the battlefield or daily life in pre-hospital care. In this work, modified cotton fabric with asymmetric wettability (Janus) was prepared using a fast and simple spray-coating strategy, where, one side of the fabric was sprayed with carboxymethyl chitosan solution to achieve hydrophilicity (0°) while the other side with hydrophobicity (152°) was built using paraffin. The hydrophilic surface could provide blood absorption and promote hemostasis, while the hydrophobic surface prevented the excessive blood absorption. The hemostatic efficiency of fabrics was tested in vitro and in vivo. Here, the carboxymethyl chitosan coated carboxymethylated cotton (CS-MCF) and Janus showed better hemostatic capacity than the cotton fabric (CF) in vitro with the lower blood clotting index. Furthermore, the Janus had better hemostatic performance than CF in rat liver animal model, and prolonged the survival time of the rats in carotid artery animal model. Therefore, Janus, with superior hemostatic efficiency over the cotton fabric, has a bright application prospect as hemostatic wound dressing. Graphic abstract

    更新日期:2020-01-23
  • Synthesis and application of a new, facile, and efficient sorbitol-based finishing agent for durable and flame retardant lyocell fibers
    Cellulose (IF 3.917) Pub Date : 2020-01-22
    Xiao-hui Liu, Chen Ding, Bo Peng, Yuan-lin Ren, Bo-wen Cheng, Sheng-gen Lin, Ju He, Xiao-wei Su

    Abstract In this paper, a simple and facile polyol sorbitol was employed to design and synthesize a novel flame retardant containing phosphorus and nitrogen by the reaction of sorbitol with phosphoric acid and urea. The obtained sorbitol-based flame retardant was then used to treat lyocell fibers by a pad-dry-cure procedure. Formaldehyde and other harmful substances were not used during the preparation of flame retardant and modified fibers. For this strategy, only water is used as solvent, and the conditions are mild, safe and environmentally friendly. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses show that the sorbitol-based flame retardant was successfully grafted onto lyocell fibers. Scanning electron microscopy analyses show that the surface morphology of the treated fibers remained unchanged. Thermogravimetric analyses imply that the residue of the treated fibers increases considerably. Vertical combustion and limit oxygen index results indicate that the treated fibers possess excellent flame retardant and durable properties. Based on the results of pyrolysis gas chromatography–mass spectrometry, thermogravimetric-infrared and Raman spectroscopy, the flame retardant operates in condensed phase and gas phase during burning of treated fibers.

    更新日期:2020-01-23
  • Mechanochemical-assisted production of 5-hydroxymethylfurfural from high concentration of cellulose
    Cellulose (IF 3.917) Pub Date : 2020-01-22
    Feng Shen, Shuang Sun, Xiao Zhang, Jirui Yang, Mo Qiu, Xinhua Qi

    Abstract Direct production of the platform chemical 5-hydroxymethylfurfural (5-HMF) from cellulose is challenging due to the rigid structure of cellulose. Herein, 5-HMF was effectively obtained from cellulose with high loading concentrations (> 20 wt.%) via an Al2(SO4)3-assisted mechanochemical method. The Al2(SO4)3 not only acted as catalyst for its Lewis and Brønsted acidity, but also assisted the disruption of the hydrogen bonds among cellulose molecules during ball milling pretreatment. The particle size and crystallinity of the cellulose greatly decreased after Al2(SO4)3-assisted ball milling pretreatment. The effects of various factors, including the organic solvent, reaction temperature and time, catalyst dose, and substrate concentration, on the yield of 5-HMF from cellulose were studied. A yield of 5-HMF up to 43.5% was obtained from cellulose via the developed mechanochemical-assisted method. A 36.1% yield of 5-HMF was retained when the initial cellulose loading concentration was as high as 21.6 wt.%. The green and efficient mechanochemical-assisted method was applicable to the efficient coproduction of 5-HMF and furfural from several waste biomass feedstocks. Graphic abstract

    更新日期:2020-01-22
  • Cationic modification of nanocrystalline cellulose from sago fronds
    Cellulose (IF 3.917) Pub Date : 2020-01-21
    I. Wayan Arnata, Suprihatin Suprihatin, Farah Fahma, Nur Richana, Titi Candra Sunarti

    Abstract Sago fronds are agricultural waste, whose availability is enormous in Indonesia, yet not optimally utilized. This research was conducted to isolate nanocrystalline cellulose from sago frond material, using sulfuric acid, with variations in hydrolysis times and cationic modifications of the nanocrystalline cellulose surface. The profiles of Fourier transform infrared spectroscopy, a scanning electron microscopy, and X-ray diffraction indicated a decrease in lignin content, hemicellulose, and fiber dimensions, during the delignification, bleaching, and hydrolysis, followed by an increase in the cellulose content and in degrees of crystallinity. The variations in hydrolysis times affected the cellulosic nanocrystalline characteristics. Longer hydrolysis times caused a decrease in the yield, thermal stability, dimensions of nanocrystalline cellulose, and an increase in the degree of crystallinity and surface charge. The modification of nanocrystalline cellulose, using cetyltrimethylammonium bromide and 3-chloro-2-hydroxypropyltrimethylammonium chloride, led to the surface of nanocrystalline cellulose becoming positively charged followed by a decrease in the degree of crystallinity and thermal stability. The resulting nanocellulose had moderate stability and the potential to be applied in wider-scaled material processing.

    更新日期:2020-01-22
  • Cellulose membranes with polyethylenimine-modified graphene oxide and zinc ions for promoted gas separation
    Cellulose (IF 3.917) Pub Date : 2020-01-21
    Ting Hou, Lian Shu, Kechun Guo, Xiong-Fei Zhang, Shuai Zhou, Ming He, Jianfeng Yao

    Abstract Cellulose-based mixed-matrix membranes containing polyethylenimine-modified graphene oxide (PEI-GO) and Zn2+ ions were fabricated and used for gas separation. The incorporation of PEI-GO effectively hinders the crystallinity of regenerated cellulose, and PEI-GO was compatible with cellulose matrix and uniformly distributed within the matrix. X-ray photoelectron spectrum revealed the amino group on GO surface can effectively coordinate with Zn2+ ions in the membrane. The Zn2+ ions content in the membranes increased when increasing the PEI-GO addition. The optimum separation performance was achieved over the membrane with 17 wt‰ PEI-GO (RC-17) wiht the highest zinc content of 24.2 wt%. The corresponding permeability of CO2 is as high as 268.9 Barrer, and the CO2/N2 and CO2/CH4 ideal selectivities could reach 48.9 and 57.4, respectively. The enhancement of CO2 transportation was attributed to both the regulated microstructure of cellulose membrane by PEI-GO and the π-complexation mechanism of Zn2+ ions with CO2 molecules. The prepared membranes would have a highly potential use in the field of CO2 separation.

    更新日期:2020-01-22
  • Recyclable ZIF-9@CA-Fe 3 O 4 /RGO/cellulose composite membrane as efficient catalysts for activating peroxymonosulfate to degrade methylene blue
    Cellulose (IF 3.917) Pub Date : 2020-01-21
    Su-Feng Zhang, Hao Li, Chen Hou, Li-Na Liu, Yang Wang, Meng-Ke Zhao, Chen Liang

    Abstract The treatment of dyes in wastewater is important to solve environmental problems. Advanced oxidation processes has been proved to be an effective treatment. In this work, a novel nanocomposite catalyst of ZIF-9@Fe3O4 (cobalt-containing zeolitic imidazolate framework-9 coated Fe3O4 nanocomposite) modified reduced graphite oxide (RGO) was prepared for the first time and coded as ZIF-9@CA-Fe3O4/RGO. Then, ZIF-9@CA-Fe3O4/RGO was immobilized on a cellulose membrane to obtain a composite membrane, which was used as a composite catalyst for activating peroxymonosulfate to degrade methylene blue (MB). The results demonstrated that the composite membrane could efficiently degrade approximately 96% of MB in 9 min without adjusting the initial pH and maintain good catalytic activity even after seven cycles. Furthermore, the composite membrane can be easily separated from the solution at the end of the reaction. This work indicates that the composite membrane has a broad application prospect in industrial applications. Graphic abstract

    更新日期:2020-01-22
  • Factors affecting the hydrolytic action of xylanase during pennisetum saccharification: role of lignin
    Cellulose (IF 3.917) Pub Date : 2020-01-21
    Xiang Chen, Donglin Xin, Fubao Fuelbiol Sun, Junhua Zhang

    Abstract Inhibition of cellulose hydrolysis has been reported extensively, however, there is a paucity of information describing the effect of lignin on xylan hydrolysis by endo-xylanase and β-xylosidase. In this report, the effects of two different lignins on enzymatic hydrolysis of isolated xylan and NaOH-pretreated pennisetum by endo-xylanase and β-xylosidase were assessed. Both acid insoluble lignin (AIL) and enzymatic hydrolysis lignin (EHL) were found to inhibit hydrolysis of endo-xylanase and β-xylosidase, and AIL had a stronger negative effect on enzymatic hydrolysis when compared with that of EHL. Results from inhibitory kinetics experiments showed that the inhibition of AIL and EHL on xylanase did not follow Michaelis–Menten kinetics. The higher adsorption capacity of AIL toward xylanase arose from its higher hydrophobicity and lower absolute zeta potential, and this likely explains the higher inhibitory effect of AIL than that of EHL. The results aid our understanding of the role of lignin in xylan hydrolysis by xylanolytic enzymes.

    更新日期:2020-01-21
  • Synthesis of polyamide-6@cellulose microfilms grafted with N -vinylcaprolactam using gamma-rays and loading of antimicrobial drugs
    Cellulose (IF 3.917) Pub Date : 2020-01-20
    G. G. Flores-Rojas, F. López-Saucedo, E. Vázquez, E. Hernández-Mecinas, L. Huerta, G. Cedillo, A. Concheiro, C. Alvarez-Lorenzo, E. Bucio

    Abstract The goal of this work was to synthesize hybrid thin films prepared combining polyamide-6 (N6) and microcellulose (CE) at various weight ratios. Products exhibited improved mechanical properties, temperature-tunable hydrophilicity, and antimicrobial features. The obtained N6@CE films were grafted with N-vinylcaprolactam (NVCL) using gamma-rays, providing temperature responsiveness in a range of 37–38 °C. The grafting degree was studied as a function of CE percentage on the film, monomer concentration, and absorbed dose. The grafting degree increased with the percentage of CE on the film, and the maximum grafting was achieved at monomer concentration and the irradiation dose of 20% NVCL and 20 kGy, respectively. NVCL grafting was confirmed by SEM, 13C-CPMAS NMR, FTIR-ATR, and XPS. SEM images attested formation of nanopores on the structure, caused by the grafting process, that consequently triggering on the new characteristics of the final materials. Potential performance of the composites as wound dressings was investigated in terms of their capability to loading and release of antimicrobial agents, such as vancomycin and benzalkonium chloride. NVCL grafting enhanced the uptake of both drugs, especially benzalkonium chloride, and regulated their release demonstrating antimicrobial effectiveness against Staphylococcus aureus. Graphic abstract

    更新日期:2020-01-21
  • Eco-friendly extraction of cellulose nanocrystals from grape pomace and construction of self-healing nanocomposite hydrogels
    Cellulose (IF 3.917) Pub Date : 2020-01-20
    Qichao Fan, Chuanjie Jiang, Wenxiang Wang, Liangjiu Bai, Hou Chen, Huawei Yang, Donglei Wei, Lixia Yang

    Abstract Extensive grape pomace from red-winemaking may seriously pollute the environment and cause the waste of resources. Cellulose after fermentation in grape pomace is suitable as the source of extract outstanding cellulose nanocrystals (CNCs). Herein, CNCs were successfully extracted from grape pomace with an eco-friendly and facile deep eutectic solvent (DES). The green DES with the composition of lactic acid/choline chloride (the molar ratio was 2:1), were used to fabricate CNCs. Importantly, the obtained CNCs as a robust nanocomposite can be successfully utilized to prepare the self-healing nanocomposite hydrogels. After added of Fe(III) and borax, the excellent self-healing performance of the guar gum-based hydrogels were achieved by the reversible noncovalent bonding interaction. Specifically, the hydrogels showed good mechanical properties (the stress was about 0.95 MPa, the strain was about 170%) and self-healing ability (the self-healing efficiency was about 90.0%). These biologically self-healing nanocomposite hydrogels can greatly broaden the recycling and utilization of grape pomace.

    更新日期:2020-01-21
  • Smart cotton fabric screen-printed with viologen polymer: photochromic, thermochromic and ammonia sensing
    Cellulose (IF 3.917) Pub Date : 2020-01-17
    Mengying Sun, Jingchun Lv, Hong Xu, Linping Zhang, Yi Zhong, Zhize Chen, Xiaofeng Sui, Bijia Wang, Xueling Feng, Zhiping Mao

    A multi-responsive chromic textile was conveniently fabricated by screen-printing with a covalent organic polymer of viologen (COP2+) on the surface of cotton fabric, which was endowed with ammonia sensing, photochromic and thermochromic capabilities. The COP2+ coated fabric (CCF) were characterized by Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. The coating treatment endowed the fabric with fast response to ammonia gas, ultraviolet light and heat without compromising its breathability, flexibility, and comfortability. The color of CCF turned from yellow to green instantly when exposed to ammonia gas and quickly returned yellow when removed from the stimulus. The reversible color transition process can also be induced by UV light (exposure for 10 s) or heat (110 °C) and is cyclable. This durable multi-responsive textile has great potential to be used as flexible sensor for environmental monitoring.

    更新日期:2020-01-17
  • Biocompatibility evaluation of bacterial cellulose as a scaffold material for tissue-engineered corneal stroma
    Cellulose (IF 3.917) Pub Date : 2020-01-17
    Chen Zhang, Jingjie Cao, Shaozhen Zhao, Honglin Luo, Zhiwei Yang, Miguel Gama, Quanchao Zhang, Dan Su, Yizao Wan

    In this work, biocompatibility of bacterial cellulose (BC) was assessed as the scaffold for corneal stroma replacement. Biocompatibility was evaluated by examining rabbit corneal epithelial and stromal cells cultured on the BC scaffold. The growth of primary cells was assessed by optical microscope, scanning electron microscope (SEM), and transmission electron microscope (TEM). Live/dead viability/cytotoxicity assay and CCK-8 assay were used to evaluate cell survival. BC was surgically implanted in vivo into a stromal pocket. During a 3-month follow-up, the biocompatibility of BC was assessed. We found that epithelial and stromal cells grew well on BC and showed a survival rate of nearly 100%. The SEM examination for both kinds of cell showed abundant leafy protrusions, spherical projections, filopodia, cytoskeletons, and cellular interconnections. The stromal cells cultured on BC arranged regularly. TEM observation revealed normal cellular microstructure and a tight adhesion to the BC membrane. In vivo observation confirmed the optical transparency of BC during 3-month follow-up. The results demonstrated that BC had good biocompatibility for the tissue engineering of corneal stroma.

    更新日期:2020-01-17
  • Simultaneous hydrogen and ethanol production in a thermophilic AFBR: a comparative approach between cellulosic hydrolysate single fermentation and the fermentation of glucose and xylose as co-substrates
    Cellulose (IF 3.917) Pub Date : 2020-01-17
    Helberth Júnnior Santos Lopes, Lucas Rodrigues Ramos, Camila Aparecida de Menezes, Edson Luiz Silva

    Abstract This study evaluated the effect of hydraulic retention time (HRT) on the simultaneous hydrogen and ethanol production in two anaerobic fluidized bed reactors (55 °C) from mono-fermentation of cellulosic hydrolysate (AFBR-C) and the fermentation of glucose and xylose as co-substrates (AFBR-GX). In AFBR-C, the HRT was decreased from 24 to 8 h, while in AFBR-GX, the HRT was decreased from 16 to 0.5 h. The carbohydrate concentration was maintained at 4 g/L (AFBR-GX) and 2 g/L (AFBR-C). In AFBR-C, the main results observed by decreasing the HRT from 24 to 8 h were the increase in H2 yield (0.6–1.1 mol H2/mol hexose) and ethanol concentration (0.02–0.48 g/L). However, the H2 yield in AFBR-GX decreased from 0.4 to 0.1 mol H2/mol hexose by decreasing the HRT from 16 to 0.5 h. Additionally, the shortest HRTs applied to the AFBR-C (8 h) and AFBR-GX (0.5 h) resulted in the maximum hydrogen production rates of 115.7 and 279.9 mL H2/h L, the maximum energy yields of 7.4 and 47.7 kJ/h L, and EtOH molar fractions of 58.9 and 50.2%, respectively. Graphic abstract

    更新日期:2020-01-17
  • Exploring the diffusion behavior of urea aqueous solution in the viscose film by ATR-FTIR spectroscopy
    Cellulose (IF 3.917) Pub Date : 2020-01-14
    Yan Dong, Lei Hou, Peiyi Wu

    The diffusion mechanism of the urea aqueous solution in the viscose film is investigated by time-resolved attenuated total reflectance-Fourier transform infrared spectroscopy combining with perturbation correlation moving window technique. Two stages can be observed during the whole diffusion process: (1) water diffuses from urea aqueous solution into the viscose film, (2) urea and water diffuse simultaneously through the viscose film. Additionally, the diffusion curve of urea in the viscose film fits Fickian diffusion model, and the diffusion coefficients can be calculated accordingly. It is shown that the diffusion rate of urea slightly decreases with increasing concentration. Furthermore, considering the frequency shift of bands attributed to C–O stretching vibration (mainly –CH2–O(6)H groups) of cellulose, it is suggested that water molecules are the dominant component interacting with cellulose by first breaking the native hydrogen-bonding network in the amorphous region and then building new cellulose-water hydrogen bonds during the diffusion process. On the other hand, urea molecules merely decrease the diffusion mobility of aqueous solutions by immobilizing the water molecules and forming urea-water associations in the viscose film. Thus, it is inferred that urea molecules play an indirect role by influencing the mobility of water molecules rather than directly interacting with cellulose chain in the viscose film during diffusion. The results herein could provide guidance in the filed of urea’s function in reactive dye printing and cellulose dissolution.

    更新日期:2020-01-15
  • Enhanced production of bacterial cellulose by Komactobacter intermedius using statistical modeling
    Cellulose (IF 3.917) Pub Date : 2020-01-14
    Shella Permatasari Santoso, Chih-Chan Chou, Shin-Ping Lin, Felycia Edi Soetaredjo, Suryadi Ismadji, Chang-Wei Hsieh, Kuan Chen Cheng

    The extraordinary nature of the bacterial cellulose (BC) biopolymer gives it potential for diverse applications; however, the low BC yield of many indigenous cellulose-producing bacteria is a persistent problem in its synthesis. In this study, the BC yield of Komactobacter intermedius (BCRC 910677) was optimized by modifying culture media. The optimal culture period, type of carbon, and nitrogen sources were evaluated using the one-factor-at-a-time approach prior to the optimization study. The optimization was done by using the response surface methodology (RSM). In RSM optimization study, a Box–Behnken design with three parameters is applied; the three parameters include fructose concentrations (X1), peptone concentrations (X2), and pH values (X3). Our optimal culture media combined 41 g/L of fructose, 38 g/L peptone, and a pH of 5.2. The predicted BC yield from the RSM model is 4.012 g/L, while BC yield of 3.906 g/L is obtained from the experiment using the optimized medium; that is only 2.64% difference. An increase in BC production of 3.82-fold (compared to the culture in HS medium) was obtained after 6-days culture. The K. intermedius investigated in this study show great potential for commercial BC productions and as feedstock. The RSM can be a promising approach to enhance BC yield since the parameters were well correlated.

    更新日期:2020-01-14
  • Low consistency refined ligno-cellulose microfibre: an MFC alternative for high bulk, tear and tensile mechanical pulp papers
    Cellulose (IF 3.917) Pub Date : 2020-01-14
    Emilia S. Jahangir, James A. Olson

    Abstract Low consistency (LC) refining of (chemi-)thermomechanical pulp (TMP) provides an energy efficient alternative to high consistency refining for pulp property development. However, the benefit of LC refining is often limited by excessive fibre shortening, lower tear strength and a reduction of bulk caused by the refining process. In this study, microfibres produced by LC refining of TMP and kraft pulp fibres were investigated for their reinforcement potential in high freeness mechanical pulp. Primary pulp at 645 mL Canadian Standard Freeness was LC refined to different energy targets as a baseline for mechanical and optical property development. In contrast, the same primary pulp was reinforced with different microfibre types in ratios that yielded the same specific energies of the baseline LC refined pulp. The study revealed that at equivalent energies, the addition of TMP microfibres to the high freeness primary pulp displayed tensile development identical to the LC refined pulp, with significantly improved tear and bulk. The addition of kraft microfibre to primary pulp produced the highest tensile and tear strength but compromised light scattering. Additionally, all microfibre composites showed improved elongation, as opposed to no notable change in elongation with conventional LC refining. This investigation proposes an alternative, cost-effective approach for developing high bulk, high strength mechanical pulp by limiting the extent of second stage refining and using LC refined microfibres for pulp reinforcement. The high tear–high bulk open construction of the composite paper is likely to benefit boxboard and packaging applications.

    更新日期:2020-01-14
  • Survey of wheat straw stem characteristics for enhanced resistance to lodging
    Cellulose (IF 3.917) Pub Date : 2020-01-13
    Ali Muhammad, Huanhuan Hao, Yali Xue, Aftab Alam, Shuming Bai, Weicheng Hu, Muhammad Sajid, Zhen Hu, Rana Abdul Samad, Zihui Li, Peiyao Liu, Zhiqiang Gong, Lingqiang Wang

    Lodging is one of the major constraints that threaten crop productivity. Although the relationship between cell walls and straw strength has been well recognized, little relevant research has been done in wheat, particularly on the monomer composition and structural characteristics of cell wall polymers and the arrangement of vascular bundles. In this study, we systematically investigated cell wall- and straw-related traits in a range of wheat germplasm resources and culm mutants using a high-throughput platform for cell wall analysis. We found that varieties with higher breaking force exhibited higher levels of crystalline cellulose but fewer hemicellulose components than other varieties. The lignin content was not consistent with the breaking force; instead, the lignin monomer constitution might be important because a significantly higher proportion of p-hydroxyphenyl (H) and guaiacyl (G) but a lower proportion of syringyl (S) monomers of lignin was found in the higher breaking force group. The crystallinity detected by X-ray diffraction was positively correlated with breaking force, indicating that the physical/chemical properties of polysaccharides also deserve attention. In terms of anatomical characteristics, the varieties with higher breaking force had a lower number and area of smaller vascular bundles in the peripheral sclerenchyma than other varieties. These results, together with the finding of a highly significant correlation between stem breaking force and straw fresh weight, 2nd internode width, flag leaf width and SiO2 content, should provide systematic information for breeding for lodging resistance.

    更新日期:2020-01-14
  • Phosphorylated cellulose nanofibers exhibit exceptional capacity for uranium capture
    Cellulose (IF 3.917) Pub Date : 2020-01-13
    Janika Lehtonen, Jukka Hassinen, Avula Anil Kumar, Leena-Sisko Johansson, Roni Mäenpää, Nikolaos Pahimanolis, Thalappil Pradeep, Olli Ikkala, Orlando J. Rojas

    Abstract We investigate the adsorption of hexavalent uranium, U(VI), on phosphorylated cellulose nanofibers (PHO-CNF) and compare the results with those for native and TEMPO-oxidized nanocelluloses. Batch adsorption experiments in aqueous media show that PHO-CNF is highly efficient in removing U(VI) in the pH range between 3 and 6. Gelling of nanofiber hydrogels is observed at U(VI) concentration of 500 mg/L. Structural changes in the nanofiber network (scanning and transmission electron microscopies) and the surface chemical composition (X-ray photoelectron spectroscopy) gave insights on the mechanism of adsorption. The results from batch adsorption experiments are fitted to Langmuir, Freundlich, and Sips isotherm models, which indicate a maximum adsorption capacity of 1550 mg/g, the highest value reported so far for any bioadsorbent. Compared to other metals (Zn, Mn, and Cu) and typical ions present in natural aqueous matrices the phosphorylated nanofibers are shown to be remarkably selective to U(VI). The results suggest a solution for the capture of uranium, which is of interest given its health and toxic impacts when present in aqueous matrices.

    更新日期:2020-01-13
  • A facile approach for fabricating silica dioxide/reduced graphene oxide coated cotton fabrics with multifunctional properties
    Cellulose (IF 3.917) Pub Date : 2020-01-13
    Xuanxuan Zhou, Wenfang Song, Guangzhou Zhu

    In this study, cotton fabrics were coated with silica (SiO2)/reduced graphene oxide (RGO) nanocomposites to obtain the asymmetric wettability (i.e., two surfaces present different wetting properties), excellent air permeating and thermal insulating properties. The coating process was conducted in three steps, i.e., preparing SiO2/GO nanocomposite inks with different SiO2 weight ratios, coating the SiO2/GO inks on cotton fabrics by spray coating and getting the SiO2/RGO fabrics using hot pressing method at a temperature of 180 °C. Morphology, chemical structures, thermal stability, wettability, air permeating and thermal insulating properties of the SiO2/RGO coated fabrics were measured. Results indicated that the SiO2 nanoparticles were evenly distributed on the surface of the fabric and enhanced its roughness, and RGO reduced its surface energy. SiO2/RGO fabric with SiO2 weight ratio of 20% showed larger water contact angle (i.e., 151.4°) than both the uncoated and coated fabrics with other SiO2 weight ratios. Besides, it had excellent stability of hydrophobicity, which could maintain the spherical shape of water droplets for 80 min in air (20 °C and 65% RH). SiO2/RGO coated fabrics also exhibited better thermal insulation performance than that of the uncoated fabrics, and the SiO2/RGO coating did not impact the air permeability of the cotton fabrics. The study provides a fast and simple spray coating method for developing fabrics with multifunctional properties, which can be used in the development of functional clothing such as winter outdoor clothing that is waterproof and provides better thermal insulation while maintaining breathability.

    更新日期:2020-01-13
  • Modeling of oxygen delignification process using a Kriging-based algorithm
    Cellulose (IF 3.917) Pub Date : 2020-01-13
    Gladson Euler, Girrad Nayef, Danyelle Fialho, Romildo Brito, Karoline Brito

    A phenomenological model of cellulose production processes presents limitations due to the presence of species and chemical reactions of complex computational representation. Modeling based on machine learning techniques is an alternative to overcome this drawback. This paper addresses the Gaussian process regressor (Kriging) method to model the oxygen delignification process in one of the largest pulp production plants of the world. Different correlation models were used to evaluate this method; furthermore, an optimization routine, based on the constrained optimization by linear approximation method, was coupled to model to minimize the objective function, which is based on the input cost. Results have shown the good performance of using a combined Kriging method with optimization routines in the non-linear industrial processes to obtain a representative model capable of providing optimized operating scenarios. A reduction of 36.5% in consumption of NaOH was obtained, while required restrictions are obeyed.

    更新日期:2020-01-13
  • Plasma activation toward multi-stimuli responsive cotton fabric via in situ development of polyaniline derivatives and silver nanoparticles
    Cellulose (IF 3.917) Pub Date : 2020-01-10
    H. Ahmed, Tawfik A. Khattab, H. M. Mashaly, A. A. El-Halwagy, Mohamed Rehan

    Abstract Cotton fabrics have been known as one of the most common fibers due to its high absorption ability to chemicals, cheapness and high strength. The functionalization of natural fabrics with conductive polymers can produce conductive surfaces of high-performance textile with multifunctional properties. In the current work, conductive natural high-performance fabric was prepared by plasma assisted coating of cotton fabrics with different conductive polymers in presence or absence of silver nanoparticles. Nanostructured thin layer of polyaniline derivative was prepared in situ after plasma activation technique. Silver nanoparticles were deposited from silver nitrate solution by taking advantage of reduction capability of the conductive polymers. By changing the type of conductive polymer and the incorporation of silver nanoparticles, high-performance fabrics with altered or improved multifunctional properties were obtained including antibacterial, electrical conductivity, thermochromism, acid sensitivity and responsiveness to metal ions for a variety of potential purposes, such as biomedical, geo-textile and antistatic applications.

    更新日期:2020-01-10
  • Boosting electrical properties of flexible PEDOT/cellulose fiber composites through the enhanced interface connection with novel combined small-sized anions
    Cellulose (IF 3.917) Pub Date : 2020-01-10
    Ziyang Chang, Xianhui An, Xueren Qian

    Abstract Rapid development of flexible electronics has raised the demand for renewable conductive materials. Biomass-derived cellulose fibers (CFs) are very promising candidates due to their outstanding advantages. In this paper, flexible, lightweight and freestanding biomaterial with high electrical conductivity was prepared via in situ chemical polymerization process using 3,4-ethylenedioxythiophene (EDOT) and CFs. In order to improve the performance of PEDOT/CFs, novel combined small-sized anion doping agents, sulphosalicylic acid (SSA) and sodium benzenesulfonate (SBS), were adopted to construct a well-organized conducting layer. The obtained PEDOT layer possessed good crystallinity and high doping level and was uniformly coated onto the surface of CFs through the dopant-dependent interface. The PEDOT:SSA-SBS/CFs exhibited electrical conductivity as high as 472 S/m and the mass loading was up to 1.92 mg/cm2. Moreover, the flexible biomaterial displayed favorable electrochemical stability. Hence, the results presented here provide a new way to produce highly conducting and flexible biomaterial. Graphic abstract

    更新日期:2020-01-10
  • Microscopic reaction mechanism of the production of methanol during the thermal aging of cellulosic insulating paper
    Cellulose (IF 3.917) Pub Date : 2020-01-10
    Yiyi Zhang, Yi Li, Hanbo Zheng, Mengzhao Zhu, Jiefeng Liu, Tao Yang, Chaohai Zhang, Yang Li

    Cellulose is the main component of transformer insulating paper. In this paper, the pyrolysis mechanism of cellulose is studied by means of computational chemistry. This study is aimed at exploring the generation process of the methanol from cellulosic insulating paper at the atomic level. A simulation scheme of cellulose pyrolysis with detailed reaction pathways for methanol production has been obtained that is not readily accessible by experiments. The molecular dynamics method based on reactive force field (ReaxFF) is adopted to simulate the pyrolysis of cellobiose. A model composed of 40 cellobioses simulated at 500–3000 K was established, and the force biased monte-carlo is mixed into ReaxFF to make it closer to the actual situation and ensure the reliability. The result reveals that the –CH2– group from the C5 (or \({\text{C}}_{ 5}^{{\prime }}\)) group in cellobioses grabbed the nearby H atom to form methanol. In the pyrolysis process of cellobioses, methanol is stable at the early stage but unstable even disappeared in the later stage. The pre-exponential factor A and activation energy Ea of the ReaxFF-MD simulation are consistent with previous experimental results. Thus, this study provides an effective theory of the methanol as an indicator to evaluate the aging condition of cellulosic insulating paper in the early stage at the atomic level.

    更新日期:2020-01-10
  • Heteropolyacids and sulfonic acid-bifunctionalized organosilica spheres for efficient manufacture of cellulose acetate propionate with high viscosity
    Cellulose (IF 3.917) Pub Date : 2020-01-09
    Huaiying Zhang, Lifu Wu, Yanfen Zhang, Sai An, Haralampos N. Miras, Yu-Fei Song

    Cellulose acetate propionate (CAP), a high value-added chemical, is traditionally prepared using H2SO4 as catalyst. Replacement of the mineral acids by solid acids is current research focus for green and sustainable production of CAP. Herein, we reported the fabrication of novel solid acid catalyst HPW/Si(Et)Si-Dim-SO3H (Si(Et)Si = ethyl-bridged organosilica and Dim = dihydroimidazole) by incorporating phosphotungstic acid (HPW) and sulfonic acid-based Brønsted acidic ionic liquids onto the organosilica nanospheres of the designed catalyst for efficient manufacture CAP via esterification. The results indicated that the as-prepared HPW/Si(Et)Si-Dim-SO3H with 7.5% HPW loading showed the best catalytic performance at 45 °C in 3 h and the resulting CAP exhibited viscosity of 447 mPa s, Mw of 102,882 and DS of 2.69. Most importantly, the HPW/Si(Et)Si-Dim-SO3H exhibited high catalytic stability over six consecutive cycles and the obtained products were stable too with similar DS, Mw and viscosity. As such, the designed heteropolyacids and sulfonic acid-bifunctionalized heterogeneous catalyst is highly promising for biomass conversion under mild conditions.

    更新日期:2020-01-09
  • Porous SBA-15/cellulose membrane with prolonged anti-microbial drug release characteristics for potential wound dressing application
    Cellulose (IF 3.917) Pub Date : 2020-01-09
    Zhi Shen, Ning Cai, Yanan Xue, Bo Yu, Jianzhi Wang, Hao Song, Hang Deng, Faquan Yu

    A sustained release of anti-infection drugs is beneficial for the reduction of required dressing change times and the protection of the granulation tissue against further infection. In this work, the strategy of encapsulating mesoporous SBA-15 particles in a permeable cellulose membrane (CM) was used in the preparation of antibacterial cellulose based composite membranes to depot store and deliver drugs with prolonged anti-microbial drug release characteristics. It was found that SBA-15 with the protection of phosphate buffered saline prefilled in SBA-15 mesoporous channel could resist strong alkali environment during composite membranes preparation and its mesoporous structure remained intact, which was verified by SEM, TEM and BET results. The resultant cellulose based composite membrane containing 30 wt% SBA-15 (denoted as P-CM-SBA (30%)) had achieved 3.6 wt% drug loading and demonstrated the sustained release of chloramphenicol for 250 h, which was resulted from SBA-15/cellulose structure-inducing two-stage release behavior. Strong antibacterial activity of P-CM-SBA (30%) against S. aureus and E. coli. could last 144 h. In addition, the tensile strength, water vapor transmission rate and swelling properties of P-CM-SBA (30%) conformed to the primary requirements of wound dressing materials. Therefore, cellulose based composite membrane with 30 wt% SBA-15 particles possesses the potential for the application of wound healing.

    更新日期:2020-01-09
  • Cellulose/biopolymer/Fe 3 O 4 hydrogel microbeads for dye and protein adsorption
    Cellulose (IF 3.917) Pub Date : 2020-01-09
    Saerom Park, Yujin Oh, Jeongchel Yun, Eunjin Yoo, Dahun Jung, Kyeong Keun Oh, Sang Hyun Lee

    Abstract Cellulose-based magnetic hydrogel microbeads were prepared through sol–gel transition using a 1-ethyl-3-methylimidazolium acetate-in-oil emulsion. Surface properties of the microbeads were altered by blending cellulose with chitosan, carrageenan, lignin, or starch. The adsorption capacity of the cellulose microbeads for crystal violet was 1.3 times higher after blending cellulose with carrageenan, while that for methyl orange was 2.0 times higher after blending cellulose with chitosan. As a model study, kinetics and isotherms for the adsorption of crystal violet on the cellulose/carrageenan microbeads were investigated to understand the effect of the biopolymer on the adsorption properties. Adsorption capacities of the cellulose microbeads for pepsin and bovine serum albumin were 1.6 and 1.2 times higher after blending cellulose with chitosan, respectively. The adsorption capacity of the cellulose/carrageenan microbeads for lysozyme was 1.2 times higher than that of the cellulose microbeads. The cellulose/alkali lignin and cellulose/starch magnetic microbeads were found to be efficient supports for immobilization of lipase. Specific activities of lipase immobilized on the cellulose/alkali lignin and cellulose/starch magnetic microbeads were 1.2- and 1.4-fold higher than that of free lipase, respectively. Under denaturing thermal conditions, the half-life of lipase immobilized on the cellulose/alkali lignin and cellulose/starch magnetic microbeads was 47- and 56-fold higher than that of free lipase, respectively. Thus, owing to their biocompatibility, biodegradability, and controllability, the cellulose/biopolymer/Fe3O4 hydrogel microbeads may have many potential applications in biocatalytic, biomedical, and environmental fields.

    更新日期:2020-01-09
  • In vivo decomposition of 13 C-labeled cellulose in the mouse
    Cellulose (IF 3.917) Pub Date : 2020-01-09
    Akari Okugawa, Kengo Ishihara, Hirokazu Taniguchi, Hiroyuki Kono, Chihiro Yamane

    Abstract The in vivo decomposition of regenerated cellulose in the digestive organs of a mouse was investigated for the first time, in anticipation of food products of regenerated cellulose becoming commercially available. In past studies, plants were grown from their seeds in a labeled CO2 environment and labeled cellulose was then extracted from these plants. The small amounts of the obtained labeled cellulose made the study of in vivo decomposition of cellulose in a digestive tract difficult. In the present study, a new method was developed to overcome this. 13C-labeled natural cellulose (13C-NC) was produced from cultures of Gluconacetobacter xylinus supplemented with 13C-labeled glucose. 13C-labeled regenerated cellulose was then prepared from a hydrolyzed 13C-NC/aqueous cuprammonium solution. 13C NMR revealed that the labeling ratio of 13C to 12C in 13C-labeled cellulose was 48.3% (mol/mol). The degree of in vivo decomposition is defined as the ratio of 13C in 13CO2 in the expired gas from mice to 13C in 13C-labeled cellulose fed to the mice. Although the decomposition rate for regenerated cellulose by enzymatic saccharification was markedly higher than that for natural cellulose under in vitro conditions, the decomposition of regenerated cellulose by mice was similar to that for natural cellulose under in vivo conditions, with decomposition rates of 18.1% (w/w) for regenerated cellulose and 15.4% (w/w) for natural cellulose. These results suggest the potential of regenerated cellulose as a low-calorie food material similar to natural cellulose.

    更新日期:2020-01-09
  • Fabrication of ZnO@Cotton fabric with anti-bacterial and radiation barrier properties using an economical and environmentally friendly method
    Cellulose (IF 3.917) Pub Date : 2020-01-08
    Ruimin Hu, Jinlong Yang, Pu Yang, Ziqin Wu, Hang Xiao, Yiping Liu, Ming Lu

    Abstract Recent years have witnessed the explosive progress of functional materials, which are made by loading various metal oxides onto fabrics. A cost-effective, facile, and simple approach of loading hexagonal zinc oxide (ZnO) sheets onto fabrics is highly desired. Here, the fabrication of the multifunctional ZnO@cotton fabrics is demonstrated using a surface micro-dissolution method by sodium hydroxide/urea (NaOH/urea) and zinc chloride (ZnCl2) aqueous solution. The hexagonal sheet ZnO forms the reflective layer to ultraviolet and near-infrared rays. The UV reflectivity of ZnO@cotton fabric is higher than the raw fabric in the range of 10.9–18.8% and UPF value of treated fabric was 100 + . Infrared barrier results were obtained through the phenomenon of heat radiation transfer obstruction, when fabrics being placed on the hot plate of 120 °C, the temperature difference between raw and treated fabrics is 6.6 °C. Also, the high antibacterial activity against Escherichia coli and Staphylococcus aureus cultures of ZnO@cotton fabric was testified. Graphic abstract

    更新日期:2020-01-08
  • Metaplexis japonica seed hair fiber: a hydrophobic natural fiber with robust oil–water separation properties
    Cellulose (IF 3.917) Pub Date : 2020-01-06
    Zongqian Wang, Dengfeng Wang, Zuguang Li, Yong Wang

    Abstract Natural fiber materials exhibit numerous advantages in the fields of oil absorption and oil–water separation owing to their abundant resources, low-cost, renewable and degradable characteristics. Herein, metaplexis japonica seed hair fiber (Mj-fiber), a hydrophobic natural fiber, is proposed as a promising candidate of oil-absorbing and oil–water separation fiber materials with excellent features such as surface superhydrophobicity, high hollow and cross-section heteromorphy. In particular, the oil-absorbing and oil–water separation abilities of such fibers are investigated for the first time. Some featured critical parameters, such as the surface static contact angle and spreading wetting process, oil absorption and oil–water separation performance of fiber assembly are systematically clarified. Mj-fibers possess outstanding superhydrophobic properties with remarkable static contact angle of 151.12°, whereas excellent lipophilicity with static contact angle of 0° against vegetable oil, motor oil and diesel oil. Mj-fibers also have good sorption capacities for vegetable oil, motor oil and diesel oil with 81.52, 77.62 and 57.22 g/g respectively, and oil retention capacities after 12 h with 79.1%, 75.4% and 72.0% respectively. More importantly, Mj-fibers as the filters exhibit an effective oil–water separation performance with high separation efficiency of 98% after four cycles, demonstrating its prominent reusability. Therefore, this work points out a new pathway of bio-based oil absorption material for water pollution caused by oil spill and other accidents with economical, environment-friendly and efficient solution.

    更新日期:2020-01-06
  • Geometric structure modification in cellulose acetate nanofibers and its impact on liquid resistance/repellency
    Cellulose (IF 3.917) Pub Date : 2020-01-04
    Jihye Lim, J. R. Kim

    Surface modification—altering geometric structures or surface energy—is a key factor in improving liquid resistance/repellency on a solid surface. In particular, roughness from geometric structures provides void spaces that enhance energy barriers in nanofibers that a liquid droplet should overcome to penetrate, thus preventing the transition of a liquid drop from the Cassie–Baxter state to Wenzel state. In this work, the design of a geometric structure that performs highly in liquid resistance/repellency was proposed by extending the Cassie–Baxter model into cellulose acetate (CA) nanofibers, entrapping SiO2 nanoparticles, and examining the impact of void spaces created by the entrapped SiO2 into nanofibers in prediction and experiment. The extended Cassie–Baxter equation was simplified using H*, which is characterized by Tnp. The prediction and measurement of the apparent contact angle \( \theta_{nf} \) in CA-SiO2 nanofabrics showed good agreement, and the results emphasized the role of void space in improving liquid resistance/repellency while minimizing chemical treatments for altering surface energy and geometric structure.

    更新日期:2020-01-04
  • Alkali treatment of hemp fibres for the production of aligned hemp fibre mats for composite reinforcement
    Cellulose (IF 3.917) Pub Date : 2020-01-04
    Tom Sunny, Kim L. Pickering, Shen Hin Lim

    The main objective of this study was to produce aligned hemp fibre mats from high strength hemp fibres using dynamic sheet forming (DSF). Alkali treatment of hemp fibre was carried out at ambient and high temperature to separate fibres. Single fibre tensile testing was used to assess the tensile properties of the fibres. It was found that the highest tensile properties were exhibited by high temperature treated fibre, whereas the tensile properties exhibited by ambient temperature treated fibre were lower than for untreated fibre. It was also found that fibre granulated after high temperature treatment, was better separated than that granulated before high temperature treatment. This well-separated fibre could successfully be formed into mats using DSF. The orientation of the formed mat was analysed using ImageJ (NIH, USA) software by which the potential of DSF to produce aligned hemp fibre mat was supported. The tensile properties of composite reinforced by these aligned hemp fibre mats were assessed.

    更新日期:2020-01-04
  • Polar molecule filtration using charged cellulose nanofiber membrane on the nanoporous alumina support for high rejection efficiency
    Cellulose (IF 3.917) Pub Date : 2020-01-03
    Eui Don Han, Chan Woo Park, Seung Hwan Lee, Byeong Hee Kim, Young Ho Seo

    Abstract In this study, we propose a charged cellulose nanofiber membrane on nanoporous alumina support (c-CNFNA), which consists of eco-friendly materials for polar molecule filtration. The CNFs were extracted from the cell walls of a tree and oxidized by TEMPO ((2,2,6,6-Tetramethylpiperidin-1-yl)oxyl) to exhibit a negative charge on its surface. The nanoporous alumina support (NAS) with high aspect ratio was fabricated by anodic aluminum oxidation process and chemical wet etching process. The charged CNFs were coated on the NAS surface for fabrication of c-CNFNA, and negatively-charged polar molecules would be rejected by the equivalent charge of c-CNFNA. To investigate the polar molecule rejection performance of c-CNFNA, a polar molecule solution was injected into the surface of c-CNFNA. Rejection efficiency was calculated by measuring the concentration of the output solution, and hydraulic resistance was calculated from the pressure loss and flow rate. The results show that the rejection efficiency of c-CNFNA is 88–99% in the first rejection. In the second rejection, for almost all cases, approximately 100% rejection efficiency was achieved.

    更新日期:2020-01-04
  • Lightweight, flexible, and multifunctional anisotropic nanocellulose-based aerogels for CO 2 adsorption
    Cellulose (IF 3.917) Pub Date : 2020-01-03
    Jiayuan Wei, Shiyu Geng, Jonas Hedlund, Kristiina Oksman

    CO2 adsorption is a promising strategy to reduce costs and energy use for CO2 separation. In this study, we developed CO2 adsorbents based on lightweight and flexible cellulose nanofiber aerogels with monolithic structures prepared via freeze-casting, and cellulose acetate or acetylated cellulose nanocrystals (a-CNCs) were introduced into the aerogels as functional materials using an impregnation method to provide CO2 affinity. The microstructure of the adsorbent was examined using scanning electron microscopy, and compression tests were performed to analyze the mechanical properties of the adsorbents. The CO2 adsorption behavior was studied by recording the adsorption isotherms and performing column breakthrough experiments. The samples showed excellent mechanical performance and had a CO2 adsorption capacity of up to 1.14 mmol/g at 101 kPa and 273 K. Compared to the adsorbent which contains cellulose acetate, the one impregnated with a-CNCs had better CO2 adsorption capacity and axial mechanical properties owing to the building of a nanoscale scaffold on the surface of the adsorbent. Although the CO2 adsorption capacity could be improved further, this paper reports a potential CO2 adsorbent that uses all cellulose-based materials, which is beneficial for the environment from both resource and function perspectives. Moreover, the interesting impregnation process provides a new method to attach functional materials to aerogels, which have potential for use in many other applications.

    更新日期:2020-01-04
  • Sustained release of an essential oil by a hybrid cellulose nanofiber foam system
    Cellulose (IF 3.917) Pub Date : 2020-01-03
    Zhengjian Zhang, Xiaojuan Wang, Meng Gao, Yanlin Zhao, Yunzhi Chen

    As natural antimicrobials, essential oils (EOs) are used for food preservation because they are both antibacterial and antioxidant. However, the preservative effect can be lost and the food destroyed before the expected date if the EOs release too quickly, resulting in excessive concentration of EOs in the package, followed by exhaustion in a short time span. Here, using cellulose nanofibers (CNFs) and thyme essential oil (EO), we demonstrate a simple and environmentally-friendly approach to fabricate a foam hybrid system (CNF-EO) for sustained release of EO. CNFs can be prepared by enzymatic hydrolysis pre-treatment and TEMPO (2, 2, 6, 6-tetramethylpiperidine-1-oxide)-mediated oxidation pre-treatment. Enzymatically hydrolyzed cellulose nanofibers (EHCN) and TEMPO-oxidized cellulose nanofibers (TOCN) are immersed in EO nanoemulsion before the freeze-drying process, which forms CNF-EO foam hybrid systems, enzymatically hydrolyzed cellulose nanofibers-EO foam (EHCN-EO) and TEMPO-oxidized cellulose nanofibers-EO foam (TOCN-EO), with porous structure and sustained EO release property. The morphology and structure of the CNF-EO foam hybrid systems were measured by scanning electron microscopy, Brunaner–Emmett–Teller and Fourier transform infrared spectrophotometer (FTIR), and the sustained-release property was measured by gas chromatography-mass spectrometer (GC–MS). Meanwhile, the antibacterial property of EHCN-EO and TOCN-EO was investigated through fresh beef antibacterial experiment. EHCN-EO displays larger pore size and smaller specific surface area than that of TOCN-EO. According to the FTIR signal, EO has been successfully incorporated into cellulose nanofiber (CNF) foams. The results of GC–MS illustrate that EHCN-EO and TOCN-EO exhibit good absorption capacity and sustained release property, of which TOCN-EO illustrates superior performance. The beef in the CNF-EO foam groups shows higher acceptability in the senses such as flavor and color at the same time, compared with the Control without essential oil at the same time and TOCN-EO is shown to be able to prolong the shelf life of fresh beef by 5 days. This CNF-EO foam hybrid system fabrication strategy would be of great importance for the preservation of fresh food.

    更新日期:2020-01-04
  • Preparation of cellulose nanofibrils from okara by high pressure homogenization method using deep eutectic solvents
    Cellulose (IF 3.917) Pub Date : 2020-01-03
    Peiyi Li, Yumeng Wang, Qingqing Hou, Hezhen Liu, Haozhe Lei, Boxing Jian, Xinping Li

    Abstract The interest in the application of deep eutectic solvents (DES) as a green solvent has increased rapidly. The application of DES in agro-industrial okara treatment can be developed into industrialization. In order to simplify the degreasing, deproteinization and cellulose extraction steps in the process of pretreating okara cellulose, a new approach to cellulose extraction from okara via one-pot DES treatment is established. Three different complexing agents, choline salts in oxalic acid, in glycerol and in urea are studied in this work. The structure and properties of cellulose nanofibers (CNFs) prepared by high pressure homogenization following pretreatment of okara with anionic systhesized DES are investigated. The effects of different systems on the degree of microfibrillation of okara are analyzed using techniques such as SEM, FTIR, TD and DTG. The results indicate that by pretreating okara with choline chloride–oxalic acid type solvent, CNFs with average diameter of 27 nm are obtained using high pressure homogenization.

    更新日期:2020-01-04
  • Composite based on poly(acrylic acid)/modified attapulgite/zinc oxide as a flame retardant of cotton fabrics
    Cellulose (IF 3.917) Pub Date : 2020-01-03
    Dangge Gao, Ping Zhao, Bin Lyu, Jianzhong Ma, Yahong Zhang

    Abstract Poly(acrylic acid)/modified attapulgite/zinc oxide composite (PAA/BF-ATP/ZnO) was prepared by acrylic acid, modified attapulgite (BF-ATP), triethoxy vinyl silane modified ZnO using in situ polymerization, and used in cotton fabric for improving the flame-retardant and UV protection properties. FT-IR and TEM results showed that PAA/BF-ATP/ZnO composite was successfully prepared. The stability, percent conversion, solid content and rotational viscosity of the composites with different ZnO content were investigated. The results showed that the conversion of composites was all above 98%, and these composites also had good stability, when the content of ZnO was 0.2–1%. Composite was loaded onto the cotton fabric by the dip-pad-dry method. The results showed that the thermal and flame retardant properties of cotton fabric were improved after treatment with the PAA/BF-ATP/ZnO, the LOI of the cotton fabrics with PAA/BF-ATP/ZnO was reached to 24.4%, which was 1.3% higher than that of PAA/BF-ATP treated cotton fabric. The burning rate was reduced to 0.68 mm/s, which was 0.24 mm/s lower than that of PAA/BF-ATP treated cotton fabric.

    更新日期:2020-01-04
  • Potential of alkali treated cornhusk film as reinforcement for epoxy laminate composites
    Cellulose (IF 3.917) Pub Date : 2020-01-03
    Harwinder Singh, Arobindo Chatterjee

    Abstract This work is aimed to explore the potential of cornhusk film (CHF) as reinforcement in the epoxy matrix. The novelty of this work is to develop a laminate composite using alkali treated cornhusk film as it is for reinforcement. Previous reported researches based on cornhusk are primarily focused on production of ethanol from the bio waste or studies related to extraction of fibres from the cornhusk and its subsequent use as the reinforcing agent in composites. Importance of the present work also includes optimization of alkali treatment conditions of CHF in order to achieve better CHF-epoxy interphase and the respective composite properties. Characterization of CHF is carried out by XRD, FTIR, SEM and mechanical properties. Increase in crystallinity and reduction in crystal size of CHF is observed after alkali treatment. XRD and FTIR results reveal that treated CHF is Iβ (monoclinic) dominant cellulose. FTIR spectra and SEM images confirm the partial delignification of CHF after alkali treatment. SEM of the fractured surface of composite exhibits improved interphase between matrix and reinforcement. DMA test shows promising result for CHF reinforced composites. Graphic abstract

    更新日期:2020-01-04
  • Energy grass/polylactic acid composites and pretreatments for additive manufacturing
    Cellulose (IF 3.917) Pub Date : 2020-01-03
    Sen Ma, Linfeng Kou, Xu Zhang, Tianwei Tan

    Abstract The aim of this study was to find the effect of ball-milling pretreatment of silvergrass and comparing the effects of pretreatment on common lignocellulosic materials such as reed, switchgrass and pennisetum to evaluate the potential of raw materials for additive manufacturing. The size of ball-milled material was much smaller than the nozzle diameter of the 3D printer and the melting point of composite was lower than that of pure PLA according to differential scanning calorimetry. The structure of the surface became smoother distinctly and biomass dispersed better in PLA matrix after ball-milling based on scanning electron microscopy. X-ray diffraction results showed that the ball-milling treatment influenced the performance of the composite by destroying the crystalline region and increasing the amorphous region of raw materials. Besides, the PLA/silvergrass composites possessed better mechanical properties of tensile strength, Young’s modulus and impact strength of 23.1 MPa, 652.9 MPa and 38.67 kJ/m2, respectively. Compared to the composites that were prepared by alkali-H2O2 (AH) and by steam explosion (SE) treatment, the composite that was prepared by acid treatment (AT) exhibited higher tensile strength, Young’s modulus and impact strength of 26.94 MPa, 720.36 MPa and 40 kJ/m2 respectively. Silvergrass/PLA composite shows better thermal stability compared to pure PLA for additive manufacturing. Moreover, AT works as a promising pretreatment method in promoting the properties of wood-plastic composite compared to UT (untreated), AH and SE. The silvergrass/PLA composite could be used for additive manufacturing after ball-milling combined with AT. Graphic abstract

    更新日期:2020-01-04
  • Antimicrobial finish of cotton fabrics treated by sophorolipids combined with 1,2,3,4-butanetetracarboxyic acid
    Cellulose (IF 3.917) Pub Date : 2020-01-03
    Cheng Huang, Chunyan Hu, Gang Sun, Bolin Ji, Kelu Yan

    Sophorolipids (SLs) are surface active glycolipids produced by nonpathogenic yeasts, and a combination of SLs with 1,2,3,4-butanetetracarboxyic acid (BTCA) was used as a new durable antimicrobial treatment method for cotton fabrics. The factors influencing the antibacterial property of the fabrics in the finishing process, such as the amount of SLs, treatment temperature, curing time, amount of BTCA, and sodium hypophosphite (SHP) were investigated. An optimized procedure for treating fabrics was two dips and two nips with a wet pickup of 90% in an aqueous solution containing 20 g/L of SHP, 40 g/L of SLs and 90 g/L of BTCA, then drying at 100°C for 2 min and curing at 120°C for 2 min. As a result, 99% of the S. aureus in a concentration of 3.0×104 CFU/mL were killed by the treated fabrics in 1 h contact according to ASTM Standards E2149-10, and the functions are durable against washing. The mechanism of BTCA crosslinking lactonic sophorolipid onto cellulose was investigated by using computational chemistry and experimental methods. As a non-irritant surfactant, sophorolipids proved to be a potential natural antimicrobial agent for textiles or medical products.

    更新日期:2020-01-04
  • Preparation of graphene-embedded hydroxypropyl cellulose/chitosan/polyethylene oxide nanofiber membranes as wound dressings with enhanced antibacterial properties
    Cellulose (IF 3.917) Pub Date : 2020-01-02
    Che-Min Lin, Yung-Chi Chang, Li-Chang Cheng, Chao-Hsien Liu, Shin C. Chang, Tzu-Yang Hsien, Da-Ming Wang, Hsyue-Jen Hsieh

    Electrospun nanofiber membranes possess high specific surface area with small pores and thus can be developed as wound dressings for absorbing exudate and also preventing bacterial penetration. In this study, hydroxypropyl cellulose (H), chitosan (C) and polyethylene oxide (P) were chosen as membrane materials to increase the hydrophilicity, anti-bacterial property, and yield of nanofibers, respectively. Additionally, graphene (G) was added to enhance the anti-bacterial property of the membranes. As indicated by SEM, the HCP and HCPG solutions (containing H:4.5 wt%, C:4.5 wt%, P:0.75 wt%, without/with G:0.5 wt%) could be electrospun into HCP and HCPG nanofiber membranes with good fiber morphology using a non-toxic solvent system. Further, the membranes were crosslinked by glutaraldehyde vapor to improve the strength. The tensile strength of the membranes was 1.38–1.82 MPa with a swelling ratio up to 1330–1410%. The water vapor transmission rate (WVTR) of wet HCPG membrane was about 3100 g/m2-day, close to the recommended WVTR of wound dressings. The anti-bacterial properties of the membranes were confirmed using three tests against Escherichia coli (Gram-negative bacterium) and Staphylococcus aureus (Gram-positive bacterium). Highly hydrophilic HCP and HCPG membranes prevented the bacterial adherence. The presence of the membranes (especially graphene-embedded HCPG membrane) also greatly reduced bacterial growth. The small pore sizes of HCP and HCPG nanofiber membranes prevented the bacterial penetration to cause infection. Taken together, the HCP and HCPG nanofiber membranes possessed good mechanical properties, appropriate WVTR and high water absorption thus suitable for absorbing wound exudate. Besides, the membranes exhibited nontoxic, anti-fibroblast adhesion and anti-bacterial properties. Therefore, HCP and HCPG nanofiber membranes have the potential to become superior anti-bacterial wound dressings.

    更新日期:2020-01-02
  • Layer-by-layer assembly of PDMS-coated nickel ferrite/multiwalled carbon nanotubes/cotton fabrics for robust and durable electromagnetic interference shielding
    Cellulose (IF 3.917) Pub Date : 2020-01-02
    Yu Wang, Wei Wang, Qingbin Qi, Nan Xu, Dan Yu

    The military and industry have multiple needs for Electromagnetic interference (EMI) shielding textiles, but it is still a huge challenge to realize integration of inorganic nanomaterials and fabric with good interface adhesion. Therefore, carefully chosen EMI materials and preparation techniques are key to provide commercially acceptable fabrics. Herein, a flexible and durable EMI shielding cotton fabric was fabricated by a layer-by-layer assembly of multiwalled carbon nanotubes (MWCNTs) and nickel ferrite (NiFe2O4) nanoparticles, following by an organic poly (dimethylsiloxane) (PDMS) coating. Benefiting from the strong interfacial interactions between MWCNTs and NiFe2O4, the efficient electrical, magnetic and thermally conductive pathways were successfully constructed on the cotton fabric. The resultant composite fabrics exhibited high electrical-magnetic properties, superior EMI shielding effectiveness of ≈ 84.5 dB in X-band with a 0.96 mm thickness, and markedly enhanced thermal conductivity (2.52 W m− 1K− 1). Furthermore, the external PDMS coating not only imparted a water-resistant feature, but also improved the structural and performance stability while maintaining satisfactory air permeability. Based on these results, the layer-by-layer assembly approach can be viewed as an efficient tool to fabricate protective textiles against EMI radiation pollution.

    更新日期:2020-01-02
  • A mild strategy to construct superhydrophobic cotton with dual self-cleaning and oil–water separation abilities based on TiO 2 and POSS via thiol-ene click reaction
    Cellulose (IF 3.917) Pub Date : 2020-01-02
    Maiping Yang, Weiqu Liu, Liyan Liang, Chi Jiang, Chunhua Liu, Yankun Xie, Hongyi Shi, Fengyuan Zhang, Ke Pi

    In this work, we proposed a mild and fluorine-free strategy for fabricating robust superhydrophobic coatings with TiO2, 3-mercaptopropyltriethoxysilane (MPTS) and polyhedral oligomeric silsesquioxanes using dip-coating and thiol-ene click reaction. The modified cotton exhibited superb superhydrophobicity with a WCA of 157.6°, which showed anti-wetting property in both water and air. Moreover, the durability of the treated cotton against acid and alkaline solutions, different temperatures, abrasion and peeling tests was verified. The highlight is the dual self-cleaning afforded by superhydrophobicity and photocatalytic degradation. The oil red O was adopted as organic pollutant model and could be decomposed completely with the aid of resultant coating after UV irradiation for 3 h. In addition, the modified cotton could be used as filter material and has the potential in the application of oil–water separation. After seven separation cycles, the separation efficiency still maintained 99.0%, while the WCA of cotton kept as high as 154.6°. Therefore, the above-mentioned features demonstrated that this fluorine-free method could reduce the usage of long-chain fluorinated polymers and prepare superhydrophobic cotton which could be applied in self-cleaning as well as oil–water separation fields.

    更新日期:2020-01-02
  • All-natural injectable hydrogel with self-healing and antibacterial properties for wound dressing
    Cellulose (IF 3.917) Pub Date : 2020-01-01
    Wenying Li, Baoxiu Wang, Minghao Zhang, Zuotong Wu, Jiaxin Wei, Yu Jiang, Nan Sheng, Qianqian Liang, Dong Zhang, Shiyan Chen

    Abstract An ideal wound dressing is highly desired for the repair of chronic wounds which should provide a moist environment, self-healing, antibacterial properties etc. Here, a novel injectable antibacterial chitosan hydrogel with good self-healing and improved mechanical properties has been prepared by dialdehyde bacterial cellulose (DABC) nanofibers as the non-toxic biocrosslinker. It is the first time to prepare the all-natural chitosan hydrogels by using ascorbic acid (VC) as solvent to dissolve chitosan and the natural fiber DABC as reinforcing and crosslinking agent. Then, the disadvantage of the use of acetic acid in the medical field was overcome and the other toxic crosslinking agents were abandoned. Accordingly, this work provides a new strategy towards fabricating the self-healing hydrogel with injectable and antibacterial properties. The new multifunctional hydrogels demonstrate strong potentiality in wound dressings or tissue engineering.

    更新日期:2020-01-02
  • Bacterial cellulose/hyaluronic acid nanocomposites production through co-culturing Gluconacetobacter hansenii and Lactococcus lactis under different initial pH values of fermentation media
    Cellulose (IF 3.917) Pub Date : 2020-01-01
    Ke Liu, Jeffrey M. Catchmark

    Abstract Providing additives into the culture media is a traditional method to manufacture bacterial cellulose (BC) based nanocomposites. This study employed a novel fermentation process, which is to co-culture Gluconacetobacter hansenii (G. hansenii) with genetically modified Lactococcus lactis (L. lactis) under static conditions, to synthesize BC/HA (hyaluronic acid) nanocomposites. The HA concentration produced by L. lactis and the dry weight of BC/HA during co-culture were regulated by the initial pH values of culture media. The incorporation of HA into the cellulose network increased the crystal sizes when the initial pH values were at 7.0, 6.2, and 5.5. The strain at break was also increased while Young’s modulus was decreased when comparing BC/HA to pure BC produced under the initial pH values of culture media at 7.0 and 6.2. When the initial pH value was 4.0, the HA concentration in the culture media exhibited the lowest level observed, which was 20.4 ± 2.3 mg/L. The BC/HA composite synthesized under this condition exhibited an improved Young’s modulus of 5029 ± 1743 MPa from 2705 ± 656 MPa associated with the pure BC. The FESEM images showed that the presence of HA dramatically changed the distribution of ribbon width in BC/HA compared to that of pure BC. The BC/HA produced by co-culture fermentation didn’t need to add extra and expensive HA during production and could be used in biomedical applications such as wound dressing and tissue engineering.

    更新日期:2020-01-01
  • A slippery oil-repellent hydrogel coating
    Cellulose (IF 3.917) Pub Date : 2020-01-01
    Jingwei Lu, Xiaotao Zhu, Bo Wang, Li Liu, Yuanming Song, Xiao Miao, Guina Ren, Xiangming Li

    Development of oil-repellent coatings that are anti-fouling with water alone is highly desirable, yet still challenging. Herein, to address this challenge, we fabricate a slippery oil-repellent hydrogel coating that exhibits oil repellency when exposed in the air as well as underwater. In the air, water wets the slippery oil-repellent hydrogel coating surface completely, while organic liquid drops such as toluene can slide off the water wetted coating surface easily. When immersed in water, the slippery oil-repellent hydrogel coating surface exhibits excellent underwater superoleophobic property with all oil contact angles more than 159° and oil adhesive forces less than 1 μN. The hydrogel coating keeps its oil repellency after long-term outdoor storage, thermal treatment, knife scratching and other treatments. Exploiting its water-attracting and oil-repelling property, the slippery oil-repellent hydrogel coated copper mesh and filter paper are demonstrated as reusable membranes to separate oil–water mixtures with separation efficiency more than 97%.

    更新日期:2020-01-01
  • Magnetized Tectona grandis sawdust as a novel adsorbent: preparation, characterization, and utilization for the removal of methylene blue from aqueous solution
    Cellulose (IF 3.917) Pub Date : 2020-01-01
    Fouzia Mashkoor, Abu Nasar

    In the submitted research work, adsorption characteristic of magnetized Tectona grandis sawdust for methylene blue from aqueous media was explored. The prepared adsorbent was characterized by SEM/EDXS, TEM, BET, XRD, FTIR, TGA-DTG/DTA, VSM, and point of zero charge. To investigate the adsorption capacity and mechanisms prevailing for the adsorption of methylene blue, batch adsorption studies were performed by changing adsorbate/adsorbent contact time, pH, initial dye concentration, and temperature. The removal efficiency was found to be 90.8% under the optimized adsorption conditions. The optimal process parameters were 1 g/L of magnetized adsorbent, 60 min contact time, pH 8, and temperature of 30 °C for 100 mg/L MB solution. The laboratory generated adsorption data was best conformed by pseudo-second-order kinetics and Langmuir adsorption isotherm models. The maximum monolayer adsorption capacity was determined to be 172.41 mg/g. The adsorption process was established to be thermodynamically feasible and accompanying with the absorption of heat and escalation of entropy. Regeneration study revealed that magnetized Tectona grandis sawdust could be reused efficaciously up to four repeated adsorption–desorption cycles using HCl as the best desorbing agent. The magnetized Tectona grandis sawdust has been proved to be novel, efficient, and cost-effective adsorbent. The combined advantages of easy preparation, good affinity towards dyes, excellent separability, reusability, and cost-effectiveness of magnetized Tectona grandis sawdust make it a novel adsorbent.

    更新日期:2020-01-01
  • Quantitative evaluation for moisture content of cellulose insulation material in paper/oil system based on frequency dielectric modulus technique
    Cellulose (IF 3.917) Pub Date : 2019-12-30
    Jiefeng Liu, Xianhao Fan, Yiyi Zhang, Hanbo Zheng, Mengzhao Zhu

    Abstract The moisture evaluation of cellulose insulation material in paper/oil system based on the frequency dielectric spectroscopy (FDS) technique has been of great interest to researchers. However, the electrode polarization effect and conductance effect can “obscure” the relaxation information in the course of the traditional FDS test, which often leads to an unreliable result. The existing researches indicated that the frequency dielectric modulus-M*(ω) could effectively enable the investigation of the relaxation behavior, which might be used to realize the condition evaluation of cellulose insulation materials in paper/oil system. Unfortunately, the M*(ω) has been rarely exploited to evaluate the moisture content (mc%) of cellulose insulation material, and the study on approach for extracting characteristic parameters based on the M*(ω) is also rare. In view of this issue, the present contribution attempt to report an available approach for extracting the characteristic parameters based on the M*(ω), and further investigate the variation laws of mc% versus the above parameters. The findings reveal that the quantitative relationship between mc% and the above parameters can be established by fitting analysis. The feasibility of the proposed parameters for moisture evaluation of cellulose insulation material is demonstrated by the newly prepared cellulose insulation samples. It is interesting to note that the average percentage errors of evaluation results corresponding to the relaxation time constant (τM) and integral value (IV) of the real part of M*(ω) are less than 8%. In that respect, the novelty of this work is that the τM and IV might be used as a potential tool for quantitative evaluation of mc% of cellulose insulation in paper/oil systems. Graphic abstract

    更新日期:2019-12-30
  • Microfibrillated lignocellulose (MFLC) and nanopaper films from unbleached kraft softwood pulp
    Cellulose (IF 3.917) Pub Date : 2019-12-28
    Erfan Oliaei, Pär A. Lindén, Qiong Wu, Fredrik Berthold, Lars Berglund, Tom Lindström

    Abstract Microfibrillated cellulose (MFC) is an important industrial nanocellulose product and material component. New MFC grades can widen the materials property range and improve product tailoring. Microfibrillated lignocellulose (MFLC) is investigated, with the hypothesis that there is an optimum in lignin content of unbleached wood pulp fibre with respect to nanofibril yield. A series of kraft fibres with falling Kappa numbers (lower lignin content) was prepared. Fibres were beaten and fibrillated into MFLC by high-pressure microfluidization. Nano-sized fractions of fibrils were separated using centrifugation. Lignin content and carbohydrate analysis, total charge, FE-SEM, TEM microscopy and suspension rheology characterization were carried out. Fibres with Kappa number 65 (11% lignin) combined high lignin content with ease of fibrillation. This confirms an optimum in nanofibril yield as a function of lignin content, and mechanisms are discussed. MFLC from these fibres contained a 40–60 wt% fraction of nano-sized fibrils with widths in the range of 2.5–70 nm. Despite the large size distribution, data for modulus and tensile strength of MFLC films with 11% lignin were as high as 14 GPa and 240 MPa. MFLC films showed improved water contact angle of 84–88°, compared to neat MFC films (< 50°). All MFLC films showed substantial optical transmittance, and the fraction of haze scattering strongly correlated with defect content in the form of coarse fibrils. Graphic abstract

    更新日期:2019-12-30
  • A new surfactant assisted acid prehydrolysis process for enhancing biomass pretreatment
    Cellulose (IF 3.917) Pub Date : 2019-12-27
    Baobin Wang, Guihua Yang, Qiang Wang, Shanshan Liu, Jiachuan Chen, Guigan Fang

    Abstract Prehydrolysis is an essential step for utilizing biomass, particularly in the Kraft-based dissolving pulp process. Once the hemicellulose was effectively extracted, it can not only upgrade the dissolving pulp, but also arise additional revenue by converting value-added products. Herein, sodium dodecyl benzene sulfonate (SDBS) was used to enhance the hemicellulose removal from poplar wood chips during mild acid hydrolysis. SDBS addition could reduce the surface tension, thus increasing the diffusion of hydrogen ion and promoting the hemicellulose and lignin dissolution. The hemicellulose removal was increased from 42.5 to 54.7% by adding SDBS in comparison with the control under condition of 170 °C and 2 h. Additionally, the lignin removal was increased from 9.6 to 19.1%. Gel permeate chronograph, scanning electron microscope, and heteronuclear single quantum coherence spectroscopy support the positive effect of SDBS addition. The properties of dissolving pulp prepared from surfactant assisted pretreatment are comparable/better than that derived from acid pretreatment. It opened a sustainable and economical way to extract hemicellulose from lignocellulose. Graphic abstract A new surfactant assisted acid prehydrolysis process for enhancing biomass pretreatment.

    更新日期:2019-12-27
  • Synthesis and characterization of dicarboxymethyl cellulose
    Cellulose (IF 3.917) Pub Date : 2019-12-24
    Ricardo Chagas, Martin Gericke, Ricardo B. Ferreira, Thomas Heinze, Luísa M. Ferreira

    Synthesis of dicarboxymethyl cellulose (DCMC) under heterogeneous conditions was examined. Cellulose was etherified using sodium bromomalonate in isopropanol/water in the presence of NaOH. The reaction was performed with five different NaOH concentrations (5–30 w/v %) and the products were characterized by anion-exchange high-performance liquid chromatography (AE-HPLC), inductively coupled plasma atomic emission- (ICP-AES), Fourier transform infrared- (FTIR), and nuclear magnetic resonance (1D-/2D-NMR) spectroscopy. Adjusting the amount of NaOH resulted in increasing functionalization of the cellulose achieving an average degree of substitution (DS) between 0.05 and 0.51. Both ICP-AES and AE-HPLC gave comparable DS values. NMR spectroscopic analysis showed that etherification occurred preferably at O-6 and, to a certain extent, at the secondary positions depending on the reaction conditions.

    更新日期:2019-12-25
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