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  • Dual-electrochromic polymer bearing oligoaniline and viologen pendants: synthesis and properties
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-12-10
    Yan Zhou, Xincai Liu, Xiaoteng Jia, Danming Chao

    Electrochromic polymers have attracted considerable attention mainly because of their potential applications in the fields of smart windows, intelligent displays and advanced devices. Herein we synthesized a dual-electrochromic polymer by introducing oligoaniline and viologen to polymeric architecture as pendants (POV). Structural identification of the monomers and polymer is performed using FTIR and 1H NMR spectroscopy. The resulting POV exhibits favorable electrochemical activity in both anodic and cathodic potential areas. Lower redox potentials are observed in the CV measurement, ascribed to the complex interplay between viologen and oligoaniline moieties. Furthermore, POV film displays approving dual-electrochromic behavior in both anodic and cathodic potential areas with desirable contrast value, moderate switching times, and acceptable coloration efficiency. This work not only presents a deep understanding of the optical-electrical dual-modulation mechanism but also paves the way for their future applications.

    更新日期:2018-12-10
  • Fabricating PVDF hollow fiber microfiltration membrane with a tenon-connection structure via the thermally induced phase separation process to enhance strength and permeability
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-12-07
    Zhenyu Cui, Wei Li, Haiyi Zeng, Xiuxiu Tang, Jing Zhang, Shuhao Qin, Na Han, Jianxin Li

    In this work, thermally induced phase separation (TIPS) method was adopted to manufacture polyvinylidene fluoride (PVDF) blend hollow fiber microfiltration membrane with tenon-connection structure, which is used to fasten in Chinese traditional building by the stronger friction between rabbet and mortise, for water treatment by blending polyvinyl butyral (PVB). In this microstructure formation process, the distribution of PVB within the matrix and its regulatory role were investigated. Especially, the comprehensive effect of rabbeting and PVB adhesion on strength (The maximum breaking strength reached 17.08MPa) was discussed. The results showed that a suitable PVB will markedly reduce the thickness of skin-layer close to the outside surface even for the solid-liquid (S-L) phase separation while the excessive PVB result in a thick skin-layer. Besides the strength, PVB markedly improved the hydrophilicity and permeability of the membrane. The breaking strength is more than 8 MPa, the maximum pure water flux is as high as 929.23L m-2 h-1 and the rejection rate of carbon particles is nearly 100% even the polymer content is only 22%. In addition, the membrane showed a β-phase and an improved anti-fouling capacity. The investigation presented a simple way to regulate microstructure, enhance mechanical strength, flux and anti-fouling capacity of the membrane via the TIPS process for water treatment.

    更新日期:2018-12-08
  • Unusual Light-Tunable Thermoresponsive Behavior of OEGylated Homopolypeptide with Azobenzene and Thioether Spacers
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-12-08
    Lin Zhang, Liang Zhao, Ying Ling, Haoyu Tang

    OEGylated homopolypeptide (i.e., P(Azo-S-OEG7)) bearing azobenzene, thioether spacers, and oligo(ethylene glycol) OEG tails were prepared via a copper-mediated 1,3-dipolar cycloaddition. P(Azo-S-OEG7) showed an upper critical solution temperature (UCST)-type thermo-, light-, and oxidation-responsive in ethanol/water solvent mixtures. The UCST-type cloud point temperature (Tcp) decreased after UV irradiation and it increased after visible light irradiation due to the trans-cis isomerization of azobenzene moieties. P(Azo-S-OEG7) can be readily oxidized in the presence of H2O2, yielding P(Azo-SOX-OEG7) with sulfone or sulfoxide spacers. P(Azo-SOX-OEG7) showed an increase of UCST-type Tcp after UV irradiation and the Tcp decreased after visible light irradiation, which is an opposite trend to the UCST-type phase behavior of P(Azo-S-OEG7) as well as previous report. P(Azo-S-OEG7) showed poor water-solubility, yet it underwent H2O2 induced solution phase transition yielding P(Azo-SOX-OEG7) with lower critical solution temperature (LCST)-type phase behavior in water. The P(Azo-SOX-OEG7) aqueous solutions showed a decrease of LCST-type Tcp after UV irradiation and consequently Tcp decreased after visible light irradiation.

    更新日期:2018-12-08
  • Binary Organocatalytic System for Ring-Opening Polymerization of ε-Caprolactone and δ-Valerolactone: Synergetic Effects for Enhanced Selectivity
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-12-08
    Yunxin Li, Na Zhao, Chuanzhi Wei, Abin Sun, Shaofeng Liu, Zhibo Li

    Phosphazenes have attracted considerable attention in the field of ring-opening polymerization (ROP) of cyclic esters. However, the application of phosphazenes as catalyst is subject to a trade-off between activity and selectivity (chain propagation versus transesterification/back-biting reaction, e.g., controlled polymerization). Despite extensive research efforts, the development of a new catalytic system having concurrent high activity and selectivity remains a great challenge. In this work, we report that the binary organocatalytic system comprised of cyclic trimeric phosphazene base (CTPB) and ureas shows both of high activity and selectivity for the ROP of ε-caprolactone (ε-CL) and δ-valerolactone (δ-VL) in the presence of alcohol as initiator. It is found that the introduction of ureas would significantly increase the catalytic selectivity during ROP without sacrificing the catalytic activity of CTPB. Moreover, the polymerizations catalyzed by the title catalytic system exhibit immortal characteristics and thus thousands equivalent of monomer could be converted to polymer efficiently with desired MWs and microstructures. Linear diblock copolymer AB and star copolymers (AB)3 with three identical diblock arms could be readily synthesized by sequential copolymerization using different alcohols as initiators.

    更新日期:2018-12-08
  • Examining the stability of membrane proteins within SMALPs
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-12-06
    Aiman A. Gulamhussein, Danyall Meah, Damian D. Soja, Stephen Fenner, Zakaria Saidani, Aneel Akram, Simran Lallie, Ashlyn Mathews, Culum Painter, Monique K. Liddar, Zain Mohammed, Lai Ki Chiu, Sabiha S. Sumar, Hannah Healy, Nabeel Hussain, Jaimin H. Patel, Stephen C.L. Hall, Timothy R. Dafforn, Alice J. Rothnie

    Amphipathic co-polymers such as styrene-maleic acid (SMA) have gained popularity over the last few years due to their ability and ease of use in solubilising and purifying membrane proteins in comparison to conventional methods of extraction such as detergents. SMA2000 is widely used for membrane protein studies and is considered as the optimal polymer for this technique. In this study a side-by-side comparison of SMA2000 with the polymer SZ30010 was carried out as both these polymers have similar styrene:maleic acid ratios and average molecular weights. Ability to solubilise, purify and stabilise membrane proteins was tested using three structurally different membrane proteins. Our results show that both polymers can be used to extract membrane proteins at a comparable efficiency to conventional detergent dodecylmaltoside (DDM). SZ30010 was found to give a similar protein yield and, SMALP disc size as SMA2000, and both polymers offered an increased purity and increased thermostability compared to DDM. Further investigation was conducted to investigate SMALP sensitivity to divalent cations. It was found that the sensitivity is polymer specific and not dependent on the protein encapsulated. Neither is it affected by the concentration of SMALPs. Larger divalent cations such as Co2+ and Zn2+ resulted in an increased sensitivity.

    更新日期:2018-12-07
  • Solvent Effect in 1,3-Butadiene Polymerization by Cyclopentadienyl Titanium Trichloride (CpTiCl3)/Methylaluminoxane (MAO) and Pentamethylcyclopentadienyl Titanium Trichloride (Cp*TiCl3)/MAO Catalysts
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-12-06
    Stefania Pragliola, Antonio Botta, Pasquale Longo

    Stereospecific cis-1,4 polymerization of 1,3 butadiene is carried out by using CpTiCl3/MAO and Cp*TiCl3/MAO catalysts in solvents (mesitylene, toluene, benzene, chlorobenzene, m-chlorobenzene, hexafluorobenzene) having different nucleophilicity. The influence of nucleophilicity of used solvent on activity and selectivity of the two considered catalytic systems is evaluated. Catalyst activity is strongly affected by used solvent, while polymer microstructure remains almost unchanged. The formation of a labile specie anti-η3-π-butenyl-Ti coordinated to solvent molecule, able to increase the rate of polymerization reaction, is hypothesized. The effect of two different external electron donors, N(C2H5)3 and P(C6H5)3, in the polymerization environment on activity and selectivity of the two considered catalytic systems is also investigated. Both N(C2H5)3 and P(C6H5)3 induce a sweeping decrease of catalyst activity, but do not cause changes in polymer microstructures.

    更新日期:2018-12-07
  • Isodimorphic aliphatic copolyester as midblock of poly(L-lactide)-based triblock copolymers towards largely enhanced impact toughness
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-12-07
    Bufeng Zhang, Zhiyong Wei, Yabiao Zhao, Rui Che, Yanshai Wang, Xuefei Leng, Yang Li

    Biobased dihydroxy-terminated aliphatic copolyesters were synthesized from melt-polycondensation of 1,6-adipic acid with 1,6-hexanediol and 1,10-decanediol. The isodimorphic behavior of the copolyesters was explored to identify the pseudo-eutectic copolyester, which was selected as macro-initiator for ring opening polymerization of L-lactide to prepare poly(L-lactide)-b-poly(hexamethylene-co-decamethylene adipate)- b-poly(L-lactide) (PLLA-b-PHDA-b-PLLA) triblock copolymers varying PLLA block length. The blocky structure was confirmed by GPC and NMR, and the influence of PLLA block length on physical and mechanical properties was investigated. Impact testing showed that the impressive impact strength was achieved, that is, the values of PLLA10-PHDA-PLLA10 and PLLA20-PHDA-PLLA20 were largely enhanced to 357.2 J/m and 259.6 J/m, respectively, about 9∼12 times greater than that of PLLA homopolymer (28.6 J/m). SEM micrographs of impact fractured surface showed that the triblock copolymers underwent a transition from brittle fracture of neat PLLA to ductile fracture, which is attributed to the introduction of flexible aliphatic polyester as middle soft building block of triblcok copolymers. This work demonstrated isodimorphic aliphatic copolyesters as midblock of PLLA-based triblock fully biobased biodegradable copolymers towards highly toughened PLLA material.

    更新日期:2018-12-07
  • New Foaming Formulations for Production of Bio-Phenol Formaldehyde Foams using raw Kraft Lignin
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-12-07
    Bing Li, Zhongshun Yuan, John Schmidt, Chunbao (Charles) Xu

    The submitted work presented new foaming formulations demonstrated for production of bio- phenol formaldehyde (BPF) resins and thermal insulation foams using raw kraft lignin (KL) as a green feedstock, reducing both petroleum-based phenol and formaldehyde by up to 50%. The obtained lignin-based BPF foams exhibited low apparent density (20 kg/m3 to 80 kg/m3), strong compressive strength (up to 1.01 MPa), excellent thermal conductivity (0.03 W/m⋅K to 0.048 W/m⋅K) and combustion properties (LOI: 32-33%), and satisfactory closed cell structure, all comparable to commercial phenol formaldehyde (PF) foams. These BPF foams, using KL, can act as flame retardant and insulation materials for construction or retrofitting of buildings, thereby future commercialization of these lignin-derived phenolic foams would lead to cleaner production of flame retardant and insulation materials using forestry and agricultural residues/waste.

    更新日期:2018-12-07
  • Highly Stable Photosensitive Supramolecular Micelles for Tunable, Efficient Controlled Drug Release
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-12-05
    Belete Tewabe Gebeyehu, Ai-Wei Lee, Shan-You Huang, Adem Ali Muhabie, Juin-Yih Lai, Duu-Jong Lee, Chih-Chia Cheng

    Simple fabrication and manipulation of multi-stimuli responsive supramolecular polymers based on multiple, self-complementary, hydrogen bond interactions with the desired self-assembly behavior and desirable micellar properties for effective drug delivery under physiological conditions remains a grand challenge. Herein, we successfully developed a dual light- and temperature-responsive uracil-based polymer, BU-PPG, that spontaneously self‐assembles to form micelle-shaped nanoparticles in phosphate-buffered saline (PBS) via supramolecular interactions between uracil moieties. The resulting micelles exhibited controlled light-sensitive photodimerization, a low critical micellization concentration, low cytotoxicity towards MCF-7 cells and tunable drug-loading capacity, as well as extremely high drug-entrapment stability in media containing serum. These features make BU-PPG micelles highly attractive as a potential candidate for safe, effective delivery of anticancer drugs. Importantly, when irradiated with UV light at 254 nm, the drug-loaded irradiated BU-PPG micelles could be easily tuned to obtain the desired phase transition temperature, remained highly stable under normal physiological conditions for prolonged periods of time, and rapidly released the encapsulated drug when the temperature was increased to 40 °C due to an efficient temperature-induced hydrophilic-hydrophobic phase transition. Collectively, these advantages suggest the newly developed BU-PPG supramolecular system may represent a promising new strategy towards the development of controlled release drug delivery systems.

    更新日期:2018-12-06
  • Impact of Branching Unit Structure on the Cloud Point of Highly Branched Polymers with Lower Critical Solution Temperature Behavior
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-12-06
    Zhaoxu Wang, Sarah Seger, Nicolay V. Tsarevsky

    The impact of the branching unit nature on the thermal dependence of the solubility of branched poly(diethylene glycol methyl ether methacrylate) (polyDEGMEMA) is studied systematically. The polymers were prepared by radical copolymerization of DEGMEMA and dimethacrylate crosslinkers with varying hydrophilicities in the presence of an efficient chain transfer agent, CBr4. Branched polyDEGMEMA containing hydrophilic groups at the branching points derived from oligo(ethylene glycol) dimethacrylate (MW 750, 2.5 mol %, vs DEGMEMA) showed a cloud point depression of 6 °C compared to linear polyDEGMEMA, while polymers with hydrophobic groups at the branching points derived from 1,6-hexanediol dimethacrylate (HDODMA, 2.5 mol % vs DEGMEMA) showed a more significant cloud point depression of 12 °C. By increasing the amount of hydrophobic crosslinker (HDODMA) from 1.25 to 10 mol %, the cloud points of the resulting branched polymers decreased gradually from 17 °C to 1 °C, and prominent solubility thermal hysteresis was observed.

    更新日期:2018-12-06
  • Glyoxal improved functionalization of starch with AZC enhances the hydrophobicity, strength and UV blocking capacities of co-crosslinked polymer
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-12-03
    Shuzhen Ni, Baobin Wang, Hui Zhang, Yongchao Zhang, Zhulan Liu, Weibing Wu, Huining Xiao, Hongqi Dai

    An effective and facile approach to functionalize starch was developed using glyoxal and ammonium zirconium carbonate (AZC) as the co-crosslinking agents. The resultant starch was characterized for chemical structure, surface morphology, thermal stability, optical and hydrophobic properties and mechanical strength. 1H and 13C nuclear magnetic resonance (NMR) spectrum confirmed the successful Schiff-base reaction on the starch. X-ray diffraction (XRD) showed that the low glyoxal dosage had an adverse impact on the degree of crystallinity. Thermalgravimetric (TG) results revealed the weakened thermal stability at the initial decomposition process and enhanced thermal stability above the maximum degradation temperature. A smoother surface on the resultant film was observed by scanning electron microscopy (SEM) after the addition of glyoxal. Significantly, enhanced mechanical and hydrophobic properties as well as ultraviolet (UV) blocking capacity of the resultant starch film were achieved at 5% (wt) glyoxal and 5% (wt) AZC content. Improved hydrophobic property and mechanical strength were also obtained even with very low dosages of glyoxal (0.5%, wt) and AZC (2.5%, wt). This new type of starch with double functionalities (i.e., hydrophobic and UV blocking capacity) provides beneficial implications for improving the performance of starch-based materials.

    更新日期:2018-12-04
  • Design of dual hydrophobic–hydrophilic polymer networks for highly lubricious polyether-urethane coatings
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-12-03
    Peter T.M. Albers, Stefan P.W. Govers, Jozua Laven, Leendert G.J. van der Ven, Rolf A.T.M. van Benthem, Gijsbertus de With, A. Catarina C. Esteves

    Bio-lubricated surfaces found in nature have inspired the design of low friction polymer coatings for biomedical applications. This work presents a systematic study of the relation between the network structure parameters and the macroscopic friction properties of highly lubricious dual hydrophobic/hydrophilic polyurethane (PU) coatings in an aqueous environment. Chemically cross-linked PU coatings were prepared by adding poly(ethylene glycol) mono–methyl ether (mPEG) as hydrophilic dangling chains, or poly(ethylene glycol) (PEG)-diol as hydrophilic elastically active network chains, to poly(propylene glycol) (PPG)-PU coating formulations. The friction behaviour of the water swollen coatings was measured using a custom-made water immersed tribology setup. Addition of the PEG segments or mPEG dangling chains to hydrophobic PPG coatings greatly enhances the lubricious properties of the coatings. These dual hydrophobic/hydrophilic diol PU network exhibit a surface with a lower coefficient of friction compared to reference coatings from either individual precursors, demonstrating a large synergistic effect between the hydrophobic PPG and the hydrophilic PEG in the coatings. Based on network structure and surface chain considerations it is hypothesized that the existence of a thin and softer hydrated surface layer on top of a less hydrated, more rigid, coating bulk layer gives rise to the observed enhanced lubricious properties, hereby mimicking to some extent bio-lubricated systems, such as cartilage.

    更新日期:2018-12-04
  • Effect of carbon nanotube length on the piezoresistive response of poly (methyl methacrylate) nanocomposites
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-12-01
    F. Avilés, A.I. Oliva, G. Ventura, A. May-Pat, A.I. Oliva-Avilés

    Multiwall carbon nanotubes (MWCNTs) were systematically fragmented using high density ultrasonic energy and used as fillers of a poly (methyl methacrylate) matrix (PMMA). MWCNT fragmentation was confirmed by scanning electron microscopy and atomic force microscopy. Dedicated MWCNT length measurements yielded a log-normal statistical distribution, with mean value of 1.33 μm for the as-received MWCNTs and 0.66 μm for the fragmented MWCNTs. Higher electrical percolation threshold and lower electrical conductivity were obtained for MWCNT/PMMA composites (0.01 to 1 wt.% MWCNT concentration) using the fragmented MWCNTs. Higher electro-mechanical (piezoresistive) sensitivity under tensile tests was measured for PMMA nanocomposites with fragmented MWCNTs, which was explained by a competition of mechanisms related to the MWCNT length.

    更新日期:2018-12-01
  • Poly(lactic acid)/Lignin Blends Prepared with the Pickering Emulsion Template Method
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-12-01
    Xiang Li, Nóra Hegyesi, Yuncong Zhang, Zhiping Mao, Xueling Feng, Bijia Wang, Béla Pukánszky, Xiaofeng Sui

    In this work, the Pickering emulsion template method was used to introduce lignin nanoparticles into poly(lactic acid) (PLA) with improved dispersion. The effect of lignin as the stabilizer of Pickering emulsions was studied in this paper, including the thermal, rheological and mechanical properties of the blends. The PLA/lignin films had reduced light transmission in the UV light region, and Young’s modulus of PLA/lignin blends increased, while their tensile strength and elongation-at-break decreased as compared to neat PLA film. The introduction of lignin improved crystallinity of PLA from 7.5% to over 15%, and increased its decomposition temperature by about 10 °C. The lignin in the blends prepared using the Pickering emulsion template approach had much larger load bearing capacity than the dispersed lignin particles in the usual melt blended material. All the results indicated that the Pickering emulsion template method improves the dispersion of lignin (over 5.0 wt%) in PLA and improve UV protection, crystallinity, decomposition temperature and Young’s modulus of PLA.

    更新日期:2018-12-01
  • Viscosity Measurement of Silicone Oils Based on Diffusion Rates in Polydiphenylacetylene Films
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-29
    Young-Ghil Choi, Giseop Kwak

    Polydiphenylacetylene derivatives with different alkyl side chains (methyl, ethyl, and n-propyl groups) via a silylene linkage (PDPA-C1, PDPA-C2, PDPA-C3) were prepared. The polymer films were examined as a solid-state sensor for measuring the viscosity of silicone oils based on the diffusion rate in the films. When the films were brought into contact with silicone oils, the fluorescence (FL) emission increased with time to reach an FL enhancing equilibrium. PDPA-C1 showed faster and more significant FL enhancement because of the larger free volume and higher degree of side phenyl stacking. The relationship between the time to reach FL enhancing equilibrium (teq) and silicone oil viscosity (η) was well expressed by a modified Forster-Hoffmann equation: log teq = C + x log η, where x is the probe-dependent constant. The slope x values, which indicate viscosity sensitivity, were 0.37 for PDPA-C1, 0.35 for PDPA-C2, and 0.36 for PDPA-C3 in thin films and 1.15 for PDPA-C1 in a thick film, indicating high viscosity sensitivity depending on film thickness. The relationship between probe FL intensity and fluid viscosity, typically expressed by the Forster-Hoffmann equation, was never established in this system. The viscosity determination method using the modified Forster-Hoffmann equation proved very useful for identifying unknown viscosities of commercial silicone oils.

    更新日期:2018-11-30
  • New degradable composite elastomers of POC/PCL fabricated via in-situ copolymerization blending strategy
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-30
    Yongfang Guo, Kai Liang, Yali Ji

    Poly(1, 8-octanediol citrate) (POC) degradable elastomer have attracted much attention due to its good biological properties. However, there is a compromise, i.e. to improve its extendibility inevitably leads to a sticky feature that causes inconvenient handling. Poly(ε-caprolactone) (PCL) is a commonly used biodegradable, flexible polyester applied in a variety of FDA-approved products. Here, an in-situ copolymerization blending strategy, i.e. melt polycondensation of citric acid and 1, 8-octanediol in the presence of PCL was adopted to produce a POC/PCL composite elastomer, in which partial PCL took part in polycondensation reaction and chemically bonded into the POC network, and the rest physically traversed within the network structure, leading to a transparent, flexible composite elastomer. The wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC) analyses confirmed a full-amorphous structure and no crystallization of PCL occurring. Moreover, the introduction of PCL not only improved extendibility but avoided stickiness. Compared to the POC, the time for curing POC/PCL prepolymers was highly reduced; and the degradation of composite elastomers in PBS solution was accelerated despite the slow degradation of PCL incorporated; additionally, surface erosion degradation presumably happened for POC/PCL elastomers, which would allow the implant to retain inner strength for a longer time.

    更新日期:2018-11-30
  • On the kinetics of micellar polymerization. Acryloylaminoalkanoates case study
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-30
    I.M. Zorin, E.P. Podolskaya, A.Yu. Bilibin

    Polymerization of sodium salts of several acryloylaminoalkanoic acids was studied in aqueous micellar solution and in non-micellizing aqueous dioxane solution in wide concentration range. Some new observations in polymerization kinetics were made using UV-Vis-spectrometry, MALDI-TOF, and real-time conductomerty measurements. Conversions, polymerization rates and reaction orders were determined, mechanisms of initiation and termination are discussed. In micellar state monomer conversion close to 100% achieved in 3-5 minutes after polymerization starts whereas in homogeneous conditions conversions do not exceed 60% in two hours. Microemulsion mechanism of polymerization suggested for monomers capable to micellization or aggregation in solution. Semi-empirical model of micellar polymerization is discussed taking into consideration Kaler-Morgan model of microemulsion polymerization.

    更新日期:2018-11-30
  • Photo-Polymerisation and Study of the Ice Recrystallisation Inhibition of Hydrophobically Modified Poly(vinyl pyrrolidone) Co-polymers
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-30
    Christopher Stubbs, Thomas R Congdon, Matthew I. Gibson

    Antifreeze, ice binding and ice nucleating proteins modulate the formation and growth of ice in biological systems, enabling extremophiles to survive in sub-zero temperatures. A common feature is their rigidity, and segregated hydrophobic and hydrophilic domains. It has been demonstrated that increased hydrophobicity in rigid, facially amphipathic, synthetic polymers enhances ice recrystallisation inhibition (IRI) activity, but has not been evaluated in flexible systems. Here photochemical RAFT/MADIX polymerisation is used to obtain well-defined poly(N-vinyl pyrrolidone), PVP, copolymers to probe the impact of hydrophobicity on ice recrystallisation inhibition in a fully flexible polymer system, to increase the understanding on how to mimic antifreeze proteins. It is observed that PVP homopolymers have only very weak, molecular weight dependent, IRI and that hydrophobic co-monomers give very modest changes in IRI, demonstrating that the spacial segregation of ‘philicities’ is crucial, and not just the overall hydrophobic content of the polymer. These results will help design the next generation of IRI active polymers for cryopreservation applications as well as aid our understanding of how biomacromolecules can inhibit ice growth.

    更新日期:2018-11-30
  • Modification of Glycidyl Methacrylate Based Block Copolymers and Their Aqueous Solution Behaviours
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-30
    Gökhan Kocak, Gökhan Solmaz, Cansel Tuncer, Vural Bütün

    Poly(glycidyl methacrylate) (PGMA) homopolymer, poly(ethylene glycol)methyl ether-block-poly(glycidyl methacrylate) (MPEG-b-PGMA), poly(methyl methacrylate)-block-poly(glycidyl methacrylate) (PMMA-b-PGMA) diblock copolymers, and poly(ethylene glycol)methyl ether-block-poly(glycidyl methacrylate)-block-poly(methyl methacrylate) (MPEG-b-PGMA-b-PMMA) triblock copolymers with different molecular weights and polymerization degrees were successfully synthesized via atom transfer radical polymerization. Epoxy groups of PGMA blocks were converted to hydroxyl and tertiary amine residues by reacting with secondary amines (morpholine, 1-methylpiperazine and diethyl amine) over a ring-opening reaction. Additionally, derivative (co)polymers containing poly(2-hydroxy-3-methyl piperazinepropyl methacrylate) (PHMPPMA) have also been quaternized with different alkyl and aryl halides. Aqueous solution behaviours of resulting functional polymers including poly(3-diethylamino-2-hydroxypropyl methacrylate) (PDEAHPMA), poly(2-hydroxy-3-morpholinepropyl methacrylate) (PHMPMA), PHMPPMA and its quaternarnized form PHMPPMA homopolymers and their block copolymers with MPEG and/or PMMA were investigated by varying solution conditions such as pH, ionic strength and temperature. Their solution behaviours were investigated by using proton nuclear magnetic resonance spectroscopy and dynamic light scattering techniques.

    更新日期:2018-11-30
  • Facile preparation of structured zwitterionic polymer substrate via sub-surface initiated atom transfer radical polymerization and its synergistic marine antifouling investigation
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-07-19
    Hui Liu, Zhengfeng Ma, Wufang Yang, Xiaowei Pei, Feng Zhou

    In this paper, using one-step method of sub-surface initiated atom transfer radical polymerization (SSI-ATRP), the novel polymer brushes accompanied with structured surface were prepared on the resin base. Compared with the traditional surface initiated atom transfer radical polymerization (SI-ATRP) method, either surface chemical composition or topography was obtained through SSI-ATRP synchronously. Besides, we found that the structured polymers brush interface had better stability and long-term synergistic antifouling effect under seawater medium through soaking experiment and ocean field assay for long time. While, the bio-fouling assay results indicated that their excellent antifouling performances would be hindered by salt responsiveness of 3-sulfopropyl methacrylate potassium salt (SPMA) polymer brushes. Because it could be screened by high salt (e.g. Ca2+ or Mg2+) concentration, which decreased the hydration effect and further weakened the antifouling effect. The zwitterionic polymer (sulfobetaine methacrylate, SBMA), however, still showed excellent antifouling performances under high salt concentration since it produced stabilized ionic bonds with water molecules than those created from other hydrophilic materials. Given this, the structured zwitterionic and anionic copolymer brushes were fabricated as well, which realized the ideal stability and long-term antifouling effect under marine environment, ever high salt concentration medium. This research is of great value to marine antifouling in the long run and some other relevant fields.

    更新日期:2018-11-29
  • Water-soluble Withaferin A polymer prodrugs via a drug-functionalized RAFT CTA approach
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-29
    Simon Van Herck, Behrouz Hassannia, Benoit Louage, Raquel Pita Compostizo, Ruben De Coen, Wim Vanden Berghe, Tom Vanden Berghe, Bruno G. De Geest

    To cope with the poor aqueous solubility of withaferin A, a broad-spectrum anti-cancer agent effective against therapy-resistant cancers, a polymer-drug conjugate was synthesized via a grafting-from-drug approach. Modification of withaferin A at the C27-OH with a chain transfer agent (CTA) for reversible addition-fragmentation chain transfer (RAFT) polymerization through a degradable ester bond was achieved with excellent control on the regioselectivity via a PFP-ester transesterification route. Subsequent RAFT polymerization with the hydrophilic N,N-dimethylacrylamide yielded a fully water-soluble conjugate. A decreased cytotoxicity in vitro indicated that withaferin A exists as a prodrug in the conjugate form and requires hydrolysis of the ester to regain its activity.

    更新日期:2018-11-29
  • Photoreactive Benzophenone as Anchor of Modifier to Construct Durable Anti-platelets Polymer Surface
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-28
    Liguang Yuan, Baoliu Qu, Jinge Li, Hongying L, Xiaoniu Yang

    Surface modification is an effective method to improve the anti-platelets property for blood-contacting biomedical materials. However, for elastomer it is still a challenge to develop a simple and versatile method to preserve desirable property of the modified surface upon repeated deformation. Herein, we synthesized a novel modifier based on the photoreactive benzophenone (BP), which is served as anchor to fix polyethylene glycols (PEG)s onto polymer surface so as to achieve durable anti-platelets surface. Upon ultra-violet (UV) exposure for a very short time, this modifier (BP-PEG) was chemically bonded onto polyurethane (PU) so that its surface property was improved. When increasing the molecular weight or incorporating sulfonate group into BP-PEG, the anti-platelets surface of PU was obtained and this property still could be preserved upon repeated deformation. The universality of this surface modifier was verified by its successful application to the other polymer substrates and improved hydrophilicity. We anticipate this work would pave a new way to construct durable surface with unique property for biomedical devices.

    更新日期:2018-11-28
  • Structure evolution in poly(ethylene-co-vinyl alcohol)/lignin blends: Effect of interactions and composition
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-26
    Emese Pregi, Dávid Kun, Vi Vu, Béla Pukánszky

    Blends were prepared from lignin and ethylene-vinyl alcohol (EVOH) copolymers to study the effect of component interactions and composition on structure. The vinyl alcohol (VOH) content of the polymers changed between 0 and 76 mol%, while the lignin content of the blends varied between 0 and 60 vol%. Low density polyethylene (LDPE) with 0 mol% VOH content was used as reference. The components were homogenized in an internal mixer and the dispersed structure of the blends was characterized by scanning electron microscopy (SEM). As an effect of the strong self-interactions of lignin, this latter forms immiscible blends with ethylene-vinyl alcohol copolymers in spite of the hydrogen bonds acting between the two components. Because of immiscibility, lignin is dispersed in the form of particles in the EVOH phase even at lignin contents as large as 60 vol%. The size of dispersed lignin particles is determined by particle break-up and coalescence, the original lignin particles of around 80 μm size break up to much smaller ones; particle sizes below one micrometer form at large vinyl alcohol contents. As equilibrium thermodynamic factors are stronger than kinetic ones in the studied system, changing shear stresses do not influence particle size much. The coalescence of particles is determined by composition and component interactions, and a simple semi-empirical model was proposed to describe the correlations of these variables quantitatively. Good agreement was found between the prediction of the model and experimental results.

    更新日期:2018-11-27
  • Nitroxide Mediated Copolymerization of acrylates, methacrylates and styrene: The importance of side reactions in the polymerization of acrylates
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-26
    Alexandre Simula, Nicholas Ballard, Miren Aguirre, Jose R. Leiza, Steven van Es, José M. Asua

    The ability to (co)polymerize acrylates, methacrylates and styrene with one alkoxyamine/nitroxide has been regarded as challenging in nitroxide mediated polymerization (NMP). The alkoxyamine 3-(((2-cyanopropan-2-yl)oxy)(cyclohexyl)amino)-2,2-dimethyl-3-phenylpropanenitrile (Dispolreg 007) has recently emerged as a robust regulator to mediate the (co)polymerization of methacrylates and styrene. Herein, the versatility of the alkoxyamine is tested to produce random and block copolymers based on n-butyl acrylate (BA). The formation and influence of dead polymer (mostly macromonomers) was studied for the homopolymerziation of n-butyl acrylate. At temperatures above 100 °C, control over the polymerization could be retained up to about 50 % conversion, with relatively narrow molar mass distributions (Mn = 34000 g.mol-1, Ð ∼ 1.7). Above this conversion side reactions, namely β-scission of mid-chain radicals generated by chain transfer to polymer and monomer self-initiation led to loss of control. This effect could be mitigated by lowering to 50 wt.% the concentration of BA and/or by lowering the temperature, or by copolymerizing BA with MMA or styrene. The chain extension of acrylate based macro-alkoxyamines led to non linear structures, due to the presence of macromonomers and residual dead chains during the production of PBA macro-alkoxyamines.

    更新日期:2018-11-27
  • Ferulic acid derivatives used as biobased powders for a convenient plasticization of polylactic acid in continuous hot-melt process
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-22
    Samir Kasmi, Antoine Gallos, Johnny Beaugrand, Gabriel Paës, Florent Allais

    Plasticizers are additives used to soften polymers, but most of them are oily or waxy and are difficult to process in a continuous hot-melt process. The plasticizing effect of four functionalized ferulic acid derivatives designed with controlled solubility parameters was investigated upon the study of both the thermal stability and the mechanical properties of polylactic acid (PLA) blends. The synthesized powders were incorporated into PLA through a continuous hot-melt process (extrusion) allowing the derivatives to turn from crystalline to an amorphous state. Such phase transition permitted the derivatives to act as plasticizers, reaching a reduction of the Young's modulus of PLA by 40% for one of the derivatives blended at 20 wt %. Another derivative decreased the glass transition of the PLA from 56.6 °C to 26.3 °C at the same content. These works demonstrate the interest of using phase transition additives to ease the mixing of efficient plasticizers by hot-melt processing.

    更新日期:2018-11-24
  • Electrochemical and Optical Characterization of a Multielectrochromic Copolymer Based on 3,4-Ethylenedioxythiophene and Functionalized Dithienylpyrrole Derivative
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-22
    Esra Tutuncu, Merve İcli Ozkut, Burcu Balci, Hasan Berk, Atilla Cihaner

    A novel conjugated copolymer, namely poly(3,4-ethylenedioxythiophene-co-1-(3,5-bis(trifluoromethyl)phenyl)-2,5-di(thiophen-2-yl)-1H-pyrrole) (P(EDOT-co-1)) was synthesized via electropolymerization method from a mixture of 3,4-ethylenedioxythiophene and 1-(3,5-bis(trifluoromethyl)phenyl)-2,5-di(thiophen-2-yl)-1H-pyrrole comonomers. The corresponding copolymer has an optical band gap of 1.7 eV and 41% optical contrast at 525 nm with a coloration efficiency of 258 cm2/C and 1.4 s switching time. The copolymer has a multielectrochromic behavior: It has dark purple, purple, gray, green and cyan colors at different oxidation states. Electrochemical stability of P(EDOT-co-1) copolymer was also investigated and it was observed that the copolymer retained 86% of its stability under ambient conditions in the presence of oxygen (without purging the electrolyte solution with any inert gas) according to the current density and 83% according to the deposited charge even after 1000 redox cycles.

    更新日期:2018-11-24
  • Surface-grafted assemblies of cyclic polymers: Shifting between high friction and extreme lubricity
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-23
    Mohammad Divandari, Giulia Morgese, Shivaprakash N. Ramakrishna, Edmondo M. Benetti

    The interfacial physicochemical properties of “brushes” constituted by cyclic polymers strongly depend on their surface density, and they can be modulated within a broader range with respect to those displayed by linear brush analogues of identical composition. This is especially valid for the nanotribological characteristics of poly(2-ethyl-2-oxazoline) (PEOXA) brushes, assembled on titanium oxide surfaces by grafting-to technique. At low surface coverage, cyclic PEOXA (C-PEOXA) grafts flatten down towards the grafting surface and provide high friction when sheared against an identical countersurface. In contrast, densely grafted C-PEOXA assemblies stretch vertically forming a molecularly smooth surface that hinders any interdigitation with the opposing brush, and dramatically reduces friction, greatly surpassing the lubricious properties typically attained by applying linear grafts.Differently from their nanotribological properties, C-PEOXA brushes always show improved resistance towards the adsorption of proteins if compared to their linear counterparts, irrespective of their grafting density. The enhancement in biopassivity achieved by applying cyclic PEOXA grafts is ascribed to their intrinsic tendency to hinder protein penetration within a brush layer.

    更新日期:2018-11-24
  • Triiodothyronine impregnated Alginate/Gelatin/Polyvinyl alcohol composite scaffold designed for exudate-intensive wound therapy
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-23
    Aishwarya Satish, R. Aswathi, J. Caroline Maria, Purna Sai Korrapati

    Chronic wound management is challenging and is further intensified due to its increasing prevalence attributed to escalation of ailments like diabetes. Presence of exudates further sustains the chronicity and is a significant burden for the healthcare sector. In this work, a wound dressing material has been formulated in the form of a lyophilized hydrogel comprising of alginate, gelatin and polyvinyl alcohol, with an aim to absorb exudates, maintain a moist environment and enhance interaction with the tissues. Triiodothyronine (active form of thyroid hormone) having vital role in repair and regeneration of tissues is incorporated in the scaffold to bolster the healing process. The fabricated scaffold is physicochemically characterized and the release of hormone has been analysed. The scaffold promotes neovasculature development, skin cell proliferation and migration with cell-biomaterial interaction and lamellipodia formation (observed by phalloidin staining). Animal experiment studies (full-thickness excision wounds created in Wistar rat model) substantiated the explicit potential of the scaffold to encourage faster wound healing. Histological studies further corroborated enhanced healing progression with blood vessel development and collagen deposition. Hence the fabricated scaffold possesses immense potential to be exploited as a chronic wound therapeutic.

    更新日期:2018-11-24
  • DOX/ICG-carrying γ-PGA-g-PLGA-based polymeric nanoassemblies for acid-triggered rapid DOX release combined with NIR-activated photothermal effect
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-23
    Kai-Ting Hou, Te-I Liu, Hsin-Cheng Chiu, Wen-Hsuan Chiang

    To boost the efficacy of chemo-photothermal cancer treatment by the intracellular rapid release of doxorubicin (DOX) combined with near-infrared (NIR)-triggered photothermal effect of indocyanine green (ICG), the poly(γ-glutamic acid)-g-poly(lactic-co-glycolic acid) (γ-PGA-g-PLGA)-based polymeric nanoassemblies (PNAs) with simultaneous incorporation of DOX and ICG were developed in this work by simple one-step nanoprecipitation. The obtained DOX/ICG-loaded PNAs were characterized by a compact γ-PGA/DOX complexes-encapsulated PLGA-rich core covered with the co-assembly of amphiphilic D-α-tocopheryl polyethylene glycol succinate (TPGS), 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)] (DSPE-PEG) and ICG molecules. The robust cargo-loaded PNAs not only promoted the photo-stability of ICG in PBS, but also reduced ICG leakage from PNAs. With the milieu pH being altered from 7.4 to 5.0, the massive disruption of ionic DOX/γ-GA complexes and PLGA degradation considerably accelerated DOX release from payload-containing PNAs. The results of in vitro cellular uptake revealed that the DOX/ICG-loaded PNAs appreciably enhanced the cellular uptake of payloads by HeLa cells. Notably, through the intracellular acid-triggered rapid DOX release combined with the ICG-based NIR-activated hyperthermia and singlet oxygen generation, the combination therapy of DOX/ICG-loaded PNAs can use lower dosage of drugs to effectively inhibit proliferation of HeLa cells compared to the chemo or photothermal treatment alone, thus showing the great potential to improve efficacy of cancer treatment.

    更新日期:2018-11-24
  • Methods to prepare dopamine/polydopamine modified alginate hydrogels and their special improved properties for drug delivery
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-20
    Bo Gao, Liheng Chen, Yilun Zhao, Xin Yan, Xiaoying Wang, Changren Zhou, Yunfeng Shi, Wei Xue

    Dopamine (DA), a typical catechol-containing monomer, which has been well reported for its excellent applications in biomedical research, was used to modify alginate (ALG) hydrogel for better gel formation and performance which are needed for drug delivery. By our design, Polydopamine (PDA) particles embedded ALG hydrogel (ALG-PDA), two types of DA and ALG co-polymerized hydrogels (ALG-DA-AS, ALG-DA-SP) which were initiated by ammonia aqueous solution (AS) and sodium periodate (SP), respectively, were successfully prepared. The status of incorporated DA/PDA and their interactions with hydrogel skeleton were investigated by chemical structure, morphology and rheology characterizations. Interestingly, a self-gelation process was discovered during ALG-DA-SP preparation, which is supposed to be the crosslinking formation via the aromatic interaction and hydrogen bonding between catechol or o-benzoquinone modified ALG molecules. Such self-crosslinked structure was proved helpful to improve the structural stability of gel even in saline environment. The effects of DA, SP concentration on the self-gelation process were discussed. The good biocompatibility of PDA material was also confirmed by a cytotoxicity test. In loading and release experiments, all the modified hydrogels were proved to have better adsorption ability to gatifloxacin (GFLX) and more steady in vitro release behavior than pristine ALG hydrogel.

    更新日期:2018-11-21
  • Poly(L-lactic acid) Twisted Nanofiber Yarn Prepared by Carbon Dioxide Laser Supersonic Multi-drawing
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-19
    Akihiro Suzuki, Yuta Shimba

    Poly(L-lactic acid) (PLLA) twisted nanofiber yarn (TNFY) was continuously prepared using a CO2-laser supersonic multi-drawing apparatus equipped with a twister-winder that offers independent control of winding speed (SW) and twisting speed (ST). TNFYs with various twist numbers (nT), twist angles, and bulk densities were produced by changing SW and ST. TNFYs with a wide nT range of 395 to 1276 T m-1 were obtained. Furthermore, the mechanical properties of the obtained TNFYs depended upon the degree of twist. The maximum Young’s modulus was 3.06 cN dtex-1 at ST=300 T min-1 and SW=0.440 m min-1, and the maximum tensile strength was 0.36 cN dtex-1 at ST=365 T min-1 and SW=0.440 m min-1. The Young’s modulus had a maximum value at optimum obliquity because the high twist reduced the contribution of fiber strength to the yarn hardness due to fiber obliquity in the yarn. The tensile strength increased with increasing ST because the frictional forces among the NFs were increased by twisting at higher ST.

    更新日期:2018-11-20
  • Theoretical investigation of Thiol-ene Click reactions: A DFT perspective
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-19
    Volkan Fındık, Isa Degirmenci, Şaron Çatak, Viktorya Aviyente

    In this study, a detailed quantum chemical investigation of the contribution of phenyl thiol derivatives in thiol-ene reaction mechanism has been carried out for the first time. DFT calculations have been used to investigate the role of substitution in thiol-ene reactions. It is well known that the reaction mechanism is strongly controlled by the kP/kCT ratio, where kP is the propagation rate constant of the thiyl radical’s addition to the alkene and kCT is the rate constant of chain transfer to a thiol. The electrophilic nature of the phenylthio radicals and the singlet-triplet (S-T) gap of alkenes are mainly responsible for the variation of the activation barriers for the propagation reaction, this demonstrates the importance of the ene functionality on the propagation reaction. A correlation between the radical stabilization energy of the carbon centered radical intermediate and the chain transfer activation energy could not be established. The transition structures of the chain transfer reactions were shown to be stabilized by intramolecular interactions, which have lowered the activation barriers. In this study, we underlie the kP/kCT ratio which is highly dependent not only on the alkene functionality, but also on the thiol functionality. Tailor-made polymers can be obtained by altering the substituents or their positions, and the computational procedure described herein is expected to guide the synthesis.

    更新日期:2018-11-20
  • Analysis of Styrene Maleic Acid Alternating Copolymer Supramolecular Assemblies in Solution by Small Angle X-Ray Scattering
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-20
    Nathan G. Brady, Shuo Qian, Barry D. Bruce

    Over the past decade, Styrene Maleic Acid alternating copolymers (SMA) have gained interest as an alternative to detergent solubilization for the isolation of integral membrane proteins. The formation of SMA lipid particles (SMALPs) presents a novel opportunity to isolate the proximal membrane environment, encompassing and throughout membrane proteins in vitro. Neither the organization or structure of SMAs in an aqueous buffer nor the mechanism by which SMA transforms the membrane bilayer into a SMALP is known. This study investigates the shape and size of diverse SMA polymer complexes/aggregates in solution at various pH, ionic strength, SMA concentration and temperature, analyzed by small angle X-ray scattering. It is clear that SMAs of differing physicochemical properties (styrene to maleic acid ratio, length of copolymer fragments and functionalization) display highly variable sizes/shapes in solution over a range of environmental conditions. The SMA supramolecular aggregates exhibit similar prolate ellipsoidal geometry of varying size, dependent on the degree of hydrophobicity of the SMA copolymer. At elevated temperature, particles composed of SMAs enriched in styrene increase in both radius of gyration and maximum particle diameter. Interestingly, we observe a correlation between the SMALP dimensions and that of native membranes. Future work will investigate if there may be a complimentary relationship between SMA aggregate dimensions and bilayer thickness (and/or protein transmembrane domain thickness), similar to what has been observed for tandem facial amphiphiles.

    更新日期:2018-11-20
  • Tunable release of Chlorhexidine from Polycaprolactone-based filaments containing graphene nanoplatelets
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-20
    Roberto Scaffaro, Andrea Maio, Luigi Botta, Emmanuel Fortunato Gulino, Daniele Gulli

    Graphene nanoplatelets (GNP) as fillers and Chlorhexidine (CHX), as an antibacterial agent, were incorporated in a polycaprolactone (PCL) matrix and processed into filaments by melt spinning. The influence of both drawing and formulation on the processability, spinnability, mechanical properties and release behaviour of these materials were deeply investigated by performing rheological, morphological analysis, tensile tests, and by measuring the cumulative release of CHX in PBS at 37 °C. Furthermore, Korsmeyer–Peppas model was adopted to study the kinetics release mechanism. The results showed that adding GNP did not alter the processability and spinnability of the systems. Furthermore, a monotonic trend of all of the properties investigated was found as a function of GNP/CHX ratio and DR: stiffness and tensile strength of such fibers were found to increase, and the release behaviour proved to be tunable. In fact, upon increasing GNP content, burst was progressively hindered at the initial stage of release, while being progressively enhanced the kinetics and amount of CHX at the final stage.

    更新日期:2018-11-20
  • Ultrasensitive Redox-responsive Porphyrin-based Polymeric Nanoparticles for Enhanced Photodynamic Therapy
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-20
    Yudong Xue, Jia Tian, Lei Xu, Zhiyong Liu, Yongjia Shen, Weian Zhang

    Stimulus-sensitive nanoparticles (NPs) have been established to widely adapt to remarkable abnormalities under the tumor microenvironment, which can observably enhance the therapeutic efficiency, improve the specific targeting ability and reduce the side effects. Photodynamic therapy (PDT) as a promising non-invasive and selective treatment for cancers through photodynamic reaction can profit from stimulus-sensitive NPs. Herein, a harmonious amphiphilic polymer (PEG-b-PTPPDS-b-PEG) with an extremely sensitive redox response is constructed via click chemistry between N3-TPPC6-N3, PEG-N3 and alkynyl-containing disulfide ester for PDT. This polymer can be self-assembled into micelles with excellent stability, ultra-fast sensitivity of redox-triggered porphyrin release, and significant photodynamic anticancer performance. The redox-triggered dissociation of micelles and the release of porphyrin are much faster than common porphyrin-containing polymer. The bio-distribution and phototoxicity of micelles against A549 cells are measured and evaluated in vitro by flow cytometry, confocal scanning laser microscopy (CLSM) and MTT assay, respectively. The results reveal that PEG-b-PTPPDS-b-PEG micelles can effectively enhance the cellular uptake and cellular internalization of porphyrin and have an extremely low dark toxicity with efficient PDT towards A549 cells. This intracellular responsive nanoparticle provides a potential strategy for anticancer therapeutic application.

    更新日期:2018-11-20
  • Biobased flexible aromatic polyester poly(1,5-pentylene terephthalate) (PPeT): Revisiting melt crystallization behaviors and thermo-mechanical properties
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-17
    Jing Lu, Lizhong Zhou, Hongzhou Xie, Linbo Wu, Bo-Geng Li

    Poly(1,5-pentylene terephthalate) (PPeT) is a less studied member of the family of terephthalic polyesters. The presence of flexible pentylene moiety and foreseeable commercialization of bio-based 1,5-pentanediol (PeDO) could make PPeT an attractive polymer. However, as a semi-crystalline flexible polyester, previous studies indicated that PPeT was hardly to crystallize nonisothermally from melt and showed clear brittleness. In this study, high molecular weight biobased PPeT (0.75 dL/g) was synthesized via melt polycondensation of terephthalic acid and biobased PeDO. It was characterized with 1H NMR and FTIR, and its crystallization/melting behaviors and thermo-mechanical properties were assessed with DSC, WAXD, TGA and tensile test. Different from previous reports, it is found that this high molecular weight PPeT product can crystallize slowly from melt, showing half crystallization time of 3.4 min when isothermally crystallized at 70 oC and melt crystallization enthalpy of 5.0 J/g at 61 oC when nonisothermally crystallized at cooling rate of 10 oC/min. It behaves as a typical flexible thermoplastic with excellent ductility rather than a brittle polymer, showing tensile modulus of 650 MPa, tensile stress at break of 21 MPa and elongation at break of 450%. It also exhibits excellent thermal stability.

    更新日期:2018-11-17
  • Nondestructive Investigation on the Nanocomposite Ordering upon Holography using Mueller Matrix Ellipsometry
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-14
    Hao Jiang, Haiyan Peng, Guannan Chen, Honggang Gu, Xiuguo Chen, Yonggui Liao, Shiyuan Liu, Xiaolin Xie

    Ordered materials, which hold organized structures of heterogeneous matter and thus always present superior performance than their non-ordered counterparts, have been constantly pursued. Nevertheless, the direct, precise and nondestructive observation of the ordering process, which is especially critical for evaluating the quality of consecutive manufacturing, remains a formidable challenge. Herein, we introduce Mueller matrix ellipsometry (MME) as a nondestructive method to quantitatively investigate the nanocomposite ordering process upon holography. This nondestructive investigation directly offers the exact width of, refractive index and nanoparticle fraction in each bright (constructive) and dark (destructive) interference area, which is impossible to be implemented using other existing techniques. Interestingly, the width of dark regions in the formed holographic gratings is observed to decrease while the width of bright regions increases with an augmentation of holographic recording time, distinct from previous width-equal assumption. Meanwhile, an apparent diffusion coefficient of 2 × 10-15 m2s-1 for nanoparticles is determined on the basis of time dependent grating parameter variation, which is 3 orders of magnitude lower than the initial value theoretically predicted by the Stokes-Einstein diffusion equation. The distinct diffusion coefficient is attributed to the rapid increase of viscosity driven by polymerization during holography. No depolarization is observed in these holographic polymer nanocomposites, indicating uniform dispersion of nanoparticles in the polymer matrices. The proposed protocol herein is envisioned to pave the way for precisely and nondestructively understanding the formation of ordered structure in electronics, photonics, photovoltaics, biomaterials and other disciplines.

    更新日期:2018-11-15
  • Novel starch-g-copolymers obtained using acrylate monomers prepared from two geometric isomers of terpene alcohol
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-15
    Marta Worzakowska

    The paper presents the studies on the optimization of the free-radical graft reaction applying the “grafting from” method of terpene acrylate monomers prepared from two geometric isomers of terpene alcohol such as trans-3,7-dimethyl-2,6-octadien-1-ol (geraniol) and cis-3,7-dimethyl-2,6-octadien-1-ol (nerol) with potato starch and the evaluation of some physico-chemical properties of the obtained materials. Based on the overall conversion (%TC) values, it was confirmed higher reactivity of neryl acrylate than geranyl acrylate in the grafting process with starch. The maximum of the grafting percent (%G) was found to be 42.8%±0.4 for neryl acrylate using 2w% of an initiator, starch to monomer ratio 1:1 and the reaction time 180 minutes. However, the maximum of the %G for geranyl acrylate was 35.6±0.4 for 2.5wt% of an initiator, starch to monomer ratio 1:1.5 during 210 minutes. ATR-FTIR and 13C CP/MAS NMR analyses affirmed the structure of novel, amphiphilic graft copolymers. SEM confirmed the creation of the materials with irregular but different morphology. Generally, starch-g-poly(geranyl acrylate) copolymer (%G 35.6±0.4) was characterized by lower moisture absorption, lower swelling in polar and non-polar solvents, higher chemical resistance towards less alkaline, acidic and neutral conditions, higher glass transition temperature (Tg) than starch-g-poly(neryl acrylate) copolymers (%G 35.3±0.2 and 42.8%±0.4). As it was proved the differences in some physico-chemical properties between those two types of the copolymers were due to their structure. However, both types of the copolymers exhibited a comparable thermal stability as it was affirmed by the TG studies. Moreover, according to the TG/FTIR results, similar gaseous products were created under the heating of the studied copolymers which was due to their comparable chemical structures.

    更新日期:2018-11-15
  • Synthesis of acid degradable oxidation responsive poly(β-thioether ester)s from castor oil
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-15
    L. Ruiz, G. Lligadas, J.C. Ronda, M. Galià, V. Cádiz

    Branched polyesters with acid degradable and oxidation responsive β-thiopropionate groups have been obtained by lipase catalyzed polycondensation of diester and hydroxyester monomers from heptanal, a castor oil derivative. Their polymerization behaviour has been investigated and poly(ethylene glycol)-b-poly(β-thioether ester) amphiphilic block copolymers have been obtained. SEC, NMR and FTIR have been employed to confirm the structure of the polymers and copolymers and DSC and TGA have been used to characterize their thermal properties. The block copolymers containing aliphatic pendant moieties self-assemble into micelles in aqueous solution, showing potential application as dual responsive systems in drug delivery.

    更新日期:2018-11-15
  • Proton conductivity and methanol permeability study of polymer electrolyte membranes with range of functionalized clay content for fuel cell application
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-15
    Faizah Altaf, Rohama gill, Rida Batool, Matthew Drexler, Faisal Alamgir, Ghazanfar Abbas, Karl Jacob

    Novel phoshorylated polyvinyl alcohol (PVA) and modified kaolinite (MK) composite membranes (P-PMK) were prepared using a solution casting method. Kaolinite was modified with a silane coupling agent, aminopropyl triethaoxy silane (APTES), in order to improve the organic/inorganic interfacial morphology. First, PVA/MK composite membranes were fabricated using various wt. %s of MK (0-20 wt. %). The prepared composite membranes were then treated with phosphoric acid (H3PO4). The properties of P-PMK composite membranes were investigated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), and AC impedance. It was found that proton conductivity was increased by increasing temperature as well as filler content yielding a maximum value of 0.0611 S cm−1 at 10wt% filler content and 70°C. The methanol permeability and water uptake were also changed by increasing filler percentage. The lowest methanol permeability, 2.87×10−6 cm-2 s−1, was obtained at 20wt. % filler content, which is lower than that of recast Nafion® 117. The results indicate that the PEM comprised of the phosphorylated PVA/MK composite has a good performance and can be a potential candidate for future PEMFC applications.

    更新日期:2018-11-15
  • Graphene And Poly (Butylene Terephthalate)-Block-Poly (Tetramethylene Glycol) Enhance The Mechanical Performance Of Polyamide-6
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-13
    Xubing Fu, Xia Dong, Yan Liu, Xingke Zhao, Na Zhang, Shunxin Qi, Dujin Wang, Guisheng Yang

    Adding graphene to a polymer matrix is an effective way of fabricating advanced materials. Few-layer graphene (FLG)/polyamide-6 (PA6)/Poly (butylene terephthalate)-block-poly (tetramethylene glycol) (PBT-PTMG) ternary nanocomposites were prepared using an in situ polymerization extrusion method. Characterizations using scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy revealed a good dispersion of graphene in the composite matrix. Under the synergistic effects of a nanofiller and an elastomer, the nanocomposites showed apparent improvements in both strength and toughness. When incorporating 0.5 wt% FLG and 10 wt% PBT-PTMG, the flexural strength, impact strength, and elongation at break increased by 45%, 217%, and 390%, respectively. The reinforcing and toughening mechanisms are discussed in detail. As this method combines both the advantages of in situ polymerization and extrusion technology, it is therefore suitable for commercial production, enabling the potential applications of polymer composites.

    更新日期:2018-11-14
  • Surface relief gratings in azopolyimides induced by pulsed laser irradiation
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-14
    Jolanta Konieczkowska, Ewa Schab-Balcerzak, Marcin Libera, Ilarion Mihaila, Ion Sava

    The communication presents a study concerning the azo-polymer response to the pulse laser irradiation, in the context of the surface relief gratings (SRGs) inscription. We used the different energy density of the laser beam (10 and 45 mJ/cm2) and their number of pulses (10 and 100) to observe the influence of the irradiation conditions on the amplitude of SRGs. The modulation of the polymer surface up to 440 nm was obtained. It was showed that key factors decided about polymer surface modulation depth, except irradiation conditions, are the azodye content in the polymer repeating units and flexibility of the polymer backbone. Moreover, unexpected effect of polymer molar masses on the SRG amplitudes was observed. The beneficial effect of higher polymer molar masses on SRGs formed using the stronger power of irradiation beam was found.

    更新日期:2018-11-14
  • All-optical spatial phase modulation in films of dye-doped DNA biopolymer
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-12
    Adrian Petris, Petronela Gheorghe, Ileana Rau, Ana-Maria Manea-Saghin, Francois Kajzar

    The deoxyribonucleic acid (DNA) is a new “green” photonic material with promising applications in organic photonics. In this paper we report the results obtained in an experimental study of the spatial phase modulation induced by light in DNA – cetyltrimethyl-ammonium chloride (CTMA) – Disperse Red (DR1) films. Using a pump-probe interferometric method, recently introduced by us, the spatial distribution of the optical phase change, its magnitude and its dependence on the incident pump intensity are determined in the investigated DNA-CTMA-DR1 films. Processes responsible for the light-induced phase modulation in DNA-CTMA-DR1 film are briefly discussed and their contribution to the overall phase modulation is estimated. The results are important for nonlinear photonics in applications based on all-optical spatial light modulation.

    更新日期:2018-11-13
  • Tuning the Life-Time of Supramolecular Hydrogels using ROS-Responsive Telechelic Peptide-Polymer Conjugates
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-12
    Ronja Otter, Christian Marijan Berac, Sebastian Seiffert, Pol Besenius

    The synthesis of multi-stimuli responsive peptide-poly(ethylene glycol) ABA-type conjugates is reported. The β-sheet encoded intramolecular folding and intermolecular self-assembly into 1D nanorods is based on a phenylalanine(F)-methionine(M)-histidine(H) FMHMHF hexapeptide sequence, and the supramolecular nanorods are stabilised by a shielding corona of hydrophilic PEG polymers. Interstrand crosslinking leads to the formation of physical networks and hydrogels at physiological pH and at room temperature. The thioether functional groups integrate oxidation responsive properties in the supramolecular polymer assemblies. We show that the glucose fuelled and glucose oxidase catalysed production of the reactive oxygen species (ROS) leads transiently stable supramolecular hydrogels that operate in a fully autonomous reaction set-up, with a tuneable gelation life-times of 1 to 12 hours. ROS play an important role in signalling cascades and inflammation processes. We are therefore particularly interested in further developing our strategy for the design of biomaterials for applications in redox microenvironments.

    更新日期:2018-11-13
  • Novel Acrylate/Organophosphorus-Based Hydrogels For Agricultural Applications. New Outlook And Innovative Concept For The Use Of 2-(Methacryloyloxy)Ethyl Phosphate As A Multi-Purpose Monomer
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-12
    Agnieszka Głowińska, Andrzej W. Trochimczuk, Anna Jakubiak-Marcinkowska

    Novel hydrogels with phosphoric acid-bearing units suitable for agricultural applications have been obtained. Introducing phosphate moieties into acrylate-based hydrogels could result in better swelling properties, especially under acidic conditions as the dissociation constants of phosphoric acid are much lower than that of acrylic acid. The presence of phosphate groups could also increase hydrogels’ biocompatibility and biodegradability, what in the case of agricultural application may be of great advantage. Presented hydrogels, besides acting as a water reservoir, have a potential to be an additional source of phosphorus - preliminary studies confirmed phosphate release as a result of hydrolysis. To obtain novel hydrogels, two organophosphorus compounds were chosen: 2-(methacryloyloxy)ethyl phosphate (MEP) acting as functional monomer and bis[2-(methacryloyloxy)ethyl] phosphate (BMEP) acting as a crosslinking agent. To the best of our knowledge, the use of these monomers in combination with acrylic acid has not been reported earlier in hydrogel synthesis. Hydrogels with nominal BMEP and MEP concentration 0.5-5.0 wt.% and 1.0-4.0 wt.%, respectively and water regain ranging from 105.5 g/g up to 2837.5 g/g were obtained. Swelling properties and response to different stimuli (pH, ionic strength etc.) were determined, indicating that synthesized materials could be successfully applied in agriculture. Moreover, obtained results gave new information about the properties of MEP, BMEP, products of their polymerization and, simultaneously, on their potential applications.

    更新日期:2018-11-12
  • Influence of the viscoelastic regime onto the UV reactivity of poly(lactic acid)
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-10
    Adam A. Marek, Vincent Verney
    更新日期:2018-11-10
  • Crosslinking dextran electrospun nanofibers via borate chemistry: Proof of concept for wound patches
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-10
    Riccardo Innocenti Malini, Jessica Lesage, Claudio Toncelli, Giuseppino Fortunato, René M. Rossi, Fabrizio Spano
    更新日期:2018-11-10
  • Advancing membrane biology with poly(styrene-co-maleic acid)-based native nanodiscs
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-10
    Michael Overduin, Bert Klumperman
    更新日期:2018-11-10
  • 更新日期:2018-11-10
  • One step synthesis of monodisperse thiol-ene clickable polymer microspheres and application on biological functionalization
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-10
    Yongping Huang, Jiayu Yuan, Jianhua Tang, Jianwen Yang, Zhaohua Zeng
    更新日期:2018-11-10
  • Versatile PISA Templates for Tailored Synthesis of Nanoparticles
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-10
    Yaoming Zhang, Zongyu Wang, Krzysztof Matyjaszewski, Joanna Pietrasik
    更新日期:2018-11-10
  • Microcellular foamed aromatic polyamides (aramids). Structure, thermal and mechanical properties
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-08
    Blanca S. Pascual, Miriam Trigo-López, Cipriano Ramos, María Teresa Sanz, Jesús L. Pablos, Félix C. García, José A. Reglero Ruiz, José Miguel García
    更新日期:2018-11-09
  • 更新日期:2018-11-09
  • Narrow dispersed linear polyethylene using cobalt catalysts bearing cycloheptyl-fused bis(imino)pyridines; probing the effects of ortho-benzhydryl substitution
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-09
    Chantsalnyam Bariashir, Zheng Wang, Hongyi Suo, Muhammad Zada, Gregory A. Solan, Yanping Ma, Tongling Liang, Wen-Hua Sun
    更新日期:2018-11-09
  • Polymyxin B immobilized nanofiber sponge for endotoxin adsorption
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-07
    Yao Huang, Zhipeng Yuan, Dan Zhao, Fang Wang, Kexin Zhang, Yansheng Li, Yongqiang Wen, Changtao Wang

    Nanofiber sponge, which showed high porosity and excellent blood compatibility, was successfully prepared by electrospinning and freeze-drying technology. The APTT (activated partial thromboplastin time) and PT (prothrombin time) of human plasma with nanofiber sponge were a little longer than control groups, which revealed the nanofiber sponge has excellent blood compatibility. By activating the carboxyl groups on the fibers, PMB (polymyxin B) was successfully immobilized on the nanofiber sponge. The adsorption performance was researched in different solutions. The adsorption capacity in physiological saline solution was around 17889 EU/mL and the adsorption equilibrium time was about 40 min. The adsorption behavior not only obeyed to second-order kinetic equation, but also was conformed to Langmuir model, which turned out to be chemical adsorption and monolayer adsorption. The endotoxin removal rate in BSA (bovine serum albumin) physiological saline solution was about 96.6 %, and the BSA recovery rate was around 75.6 %, which indicated the PMB immobilized nanofiber sponge adsorbed endotoxin selectively. The endotoxin removal rate of normal nanofiber sponge was about 17.3 %, while it was around 99.6 % when it comes to PMB immobilized-nanofiber sponge, which manifested PMB played an important role in endotoxin adsorption. The endotoxin removal rate in human plasma reached 90 %, and the adsorption reached equilibrium within 60 min, which proved the PMB immobilized-nanofiber sponge would have great potential for applying in clinical blood purification.

    更新日期:2018-11-08
  • Cationic polyesters with antibacterial properties: Facile and controllable synthesis and antibacterial study
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-07
    Jia Yan, Liuchun Zheng, Kun Hu, Luhai Li, Chuncheng Li, Li Zhu, Hengliang Wang, Yaonan Xiao, Shaohua Wu, Jiajian Liu, Bo Zhang, Fan Zhang
    更新日期:2018-11-08
  • 更新日期:2018-11-08
  • 更新日期:2018-11-05
  • 更新日期:2018-11-05
  • Immobilization of Fe@Au superparamagnetic nanoparticles on polyethylene
    Eur. Polym. J. (IF 3.741) Pub Date : 2018-11-02
    O. Kvitek, A. Reznickova, A. Zelenakova, V. Zelenak, M. Orendac, V. Svorcik
    更新日期:2018-11-05
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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