Synergistic enhancement effect of nano-SiO2 and ionic liquids on mechanical properties and impact resistance of polyurethane elastomer

doi:10.1016/j.coco.2021.100876

Composites Communications

Volume 27, October 2021, 100876

https://doi.org/10.1016/j.coco.2021.100876 Get rights and content

Highlights

•
A novel nano-polymer prepared by double bond polymerization is creatively applied in impact resistance field.
•
Synergistic enhancement effect of nano-SiO₂ and IL is investigated.
•
The composite materials (PUE-2%IL@SiO₂) has excellent energy absorption capacity (an increase of 18.87 %).

Abstract

A nano-polymer (IL@SiO₂) was synthesized by double bond polymerization and creatively applied to polyurethane elastomer (PUE-IL@SiO₂). The mechanical properties and energy absorption of PUE-IL@SiO₂ at static compression and dynamic impact were studied, respectively. The results show that: compared with pure PUE, the static compressive properties and dynamic impact resistance of PUE with a loading of IL@SiO₂ of 2wt% are the best, and the static and dynamic compressive yield strength are improved by 216.15% and 190.68% compared with PUE respectively. Moreover, the energy absorption of PUE-2%IL@SiO₂ is improved by 18.87% compared with PUE. The composite materials (PUE-2%IL@SiO₂) also has excellent deformation recovery performance. These outstanding mechanical properties illustrate the IL@SiO₂ is excellent impact resistance and reinforcing materials for PUE.

Introduction

Many circumstances such as construction engineering and industrial equipment face some new challenges constantly, such as weak impact resistance, low bearing capacity, and poor cycle service performance. How to effectively solve these problems effectively has always been the research focus of engineers and scholars. Polyurethane elastomer (PUE) is widely used in various protective fields because of its ideal impact resistance, mechanical properties, excellent viscoelastic and self-healing characteristics [1,2]. However, these properties cannot meet the requirements of modern materials, such as high impact strength, excellent energy absorption efficiency and durability.

Researchers have developed various solutions to improve those properties. One of the most effective and simple method is to employ fillers to prepare composite materials [3,4]. For example, Wang et al. [5] prepared coating materials with excellent impact resistance and flame retardancy by co-curing lignin and PUE. Ye et al. [6] creatively applied multi-walled carbon nanotubes (MWCNTs) to thermoplastic PUE to prepare a hierarchical porous super-flexible material with excellent compression resistance and resilience. Among them, nano-SiO₂ is widely used to improve the mechanical properties of materials due to the excellent strength and “nano-effect” [7]. However, the addition of pure SiO₂ to the matrix only through physical blend can improve the strength of the matrix to a certain extent, but it usually leads to the decline of other properties [8]. For instance, the fluidity of the matrix will not only become worse with the increase of SiO₂ content, the severe agglomeration of nanoparticles will also lead to poor interfacial interaction between the filler and the matrix, thereby reducing the mechanical properties [9,10]. As we all know, in addition to the properties of fillers and polymers, the interface between fillers and polymers also plays an important role in determining the final properties of nanocomposites. Therefore, surface modification is an effective method to control the overall performance of nanocomposites [10,11].

Recently, ionic liquids (ILs) have attracted widespread interest due to their structural design, special cation and anion structure, high solubility, and other physical and chemical properties [[12], [13], [14]]. Studies have shown that the use of ILs can improve the dispersion of fillers [[15], [16], [17], [18]]. For some composite materials containing nanofillers, ILs can be used as a plasticizer to increase the flexibility of composite materials [[18], [19], [20], [21]]. Previously, there were also some studies on the preparation of polyurethane foam by simple mixing of nano-SiO₂ and ILs, and its compressive strength increased by 161% [22]. Some studies have shown that ILs can also improve the toughness of the material to a certain extent, but the toughness enhancement is mainly attributed to the non-covalent bonds (such as hydrogen bonds and ionic bonds) [23].

Based on the above, the innovative ideal of synergistic effect composed of nano-SiO₂ and ILs can be used to improve the impact resistance of the PUE matrix. The main idea is that ILs can be designed to be grafted onto the surface of the nano-SiO₂ by double bond polymerization instead of simply physical mixing. When being impacted by external forces, nano-SiO₂ and ILs will play a synergistic enhancement effect to resist and consume the impact force. In this paper, a spherical polymer (IL@SiO₂) was synthesized and creatively applied to polyurethane elastomer (PUE-IL@SiO₂) to improve its impact resistance. And many methods were used to prove the impact resistance and synergistic enhancement effect of the composites.

Section snippets

Materials

SiO₂ particles (500 nm) were purchased from Aladdin. Other chemicals (analytical purity) used in this study were purchased from Macklin. The PUE materials were provided by Qingdao Green World New Material Technology Co., Ltd.

Preparation of KH570 modified SiO₂

Added 2 g KH570 to the mixture of 60 mL ethanol and 20 mL H₂O adjusted the PH to 4–5, and mixed for about 30 min. Subsequently, 10.0 g SiO₂ was added into the mixture, and stirred at 60 °C for 6 h. Then, it was washed several times with ethanol and dried at 60 °C for 12 h.

Synthesis of IL ([EOHVIm][Br])

Structure characterizations

FT-IR, TEM and ¹H-NMR were used to prove the successful synthesis of IL@SiO₂. From the FT-IR spectra in Fig. 2a, it can be seen that a new adsorption of C double bond O appears at 1720 cm^{− 1}, which can also prove the successful grafting of the KH570. Correspondingly, as shown in the TEM images (Fig. 2b), there are serious agglomeration phenomenon and irregular morphology in SiO₂. Compared with SiO₂, the images of Fig. 2c also show that the KH570–SiO₂ has excellent dispersion performance. These evidences of

Conclusions

In this paper, a nano-polymer was synthesized and applied to PUE to study its performance at high-speed impact. It is proposed that the performance improvement of PUE-IL@SiO₂ is based on the synergistic enhancement effect of nano-SiO₂ and IL. The yield strength of the composite material under static compression is 216.15% higher than that of PUE. Under high-speed impact, the impact yield strength of the composite material is increased by 190.68%, the energy absorption is increased by 18.87%

CRediT authorship contribution statement

Fan Hu: contributed equally, Writing – original draft, Data curation, Formal analysis, Investigation. Feng Qi: contributed equally, Validation, Investigation. Zehui Xiang: Formal analysis, Software. Biao Zhang: Supervision, Writing – review & editing. Fugang Qi: Visualization, Validation, Supervision. Nie Zhao: Conceptualization, Supervision. Xiaoping Ouyang: Project administration, Supervision.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This work was supported by Educational Commission of Hunan Province of China (20B579, 19B570); Innovation Team of Hunan Province (2018RS3091); National Natural Science Foundation of China (11605149, 11872053); Hunan Provincial Natural Science Foundation of China (2020JJ4086, 2020JJ5530).

References (30)

S. Naheed et al.
Molecular engineering and morphology of polyurethane elastomers containing various molecular weight of macrodiol
Mater. Sci. Eng. B-Adv.
(2021)
A.W. Jatoi
Polyurethane nanofibers incorporated with ZnAg composite nanoparticles for antibacterial wound dressing applications
Compos. Commun.
(2020)
C.W. Heng et al.
Effect of graphene loading on mechanical properties of polyurethane elastomer
Mater. Today. Proc.
(2019)
S. Zhao et al.
Organic-inorganic nanohybrid polyurethane elastomer based on dopamine-mediated biomimetic co-deposition thought toward multiple improved properties
Appl. Surf. Sci.
(2019)
Y. Wang et al.
A novel phosphorus-containing lignin-based flame retardant and its application in polyurethane
Compos. Commun.
(2020)
S. Ye et al.
Superhydrophobic and superelastic thermoplastic polyurethane/multiwalled carbon nanotubes porous monolith for durable oil/water separation
Compos. Commun.
(2020)
H. Bahramnia et al.
Epoxy/polyurethane hybrid nanocomposite coatings reinforced with MWCNTs and SiO2 nanoparticles: processing, mechanical properties and wear behavior
Surf. Coat. Tech.
(2021)
C. Zheng et al.
Suspension of surface-modified nano-SiO2 in partially hydrolyzed aqueous solution of polyacrylamide for enhanced oil recovery
Colloid. Surface. A.
(2017)
Y. Wan et al.
Recent advances in polymer-based electronic packaging materials
Compos. Commun.
(2020)
H.H. Le et al.
Selective wetting of carbon nanotubes in rubber compounds–Effect of the ionic liquid as dispersing and coupling agent
Eur. Polym. J.
(2016)

H.H. Le et al.

Effect of different ionic liquids on the dispersion and phase selective wetting of carbon nanotubes in rubber blends

Polymer

(2016)

J. Narongthong et al.

An efficient highly flexible strain sensor: enhanced electrical conductivity, piezoresistivity and flexibility of a strongly piezoresistive composite based on conductive carbon black and an ionic liquid

Compos. Part. A-Appl. S.

(2018)

C. Chen et al.

Epoxy/ionic liquid-like MWCNTs composites with improved processability and mechanical properties

Compos. Commun.

(2019)

K. Oh et al.

Highly stretchable dielectric nanocomposites based on single-walled carbon nanotube/ionic liquid gels

Compos. Sci. Technol.

(2013)

C. Chen et al.

Noncovalent engineering of carbon nanotube surface by imidazolium ionic liquids: a promising strategy for enhancing thermal conductivity of epoxy composites

Compos. Part. A-Appl. S.

(2019)

Cited by (17)

Carbon quantum dots enhanced polyurethane-urea nanocomposites with mechanical reinforcement and room-temperature self-healing performance
2024, Applied Surface Science
Developing high-performance polymer composites with self-healing and recyclable performance is crucial for long-term durability of the devices. This paper presents a novel method by incorporating carbon quantum dots (CQDs) into the chain extension reaction of polymers to construct self-healing polyurethane-urea (PUU) with excellent integrated mechanical and multi-recyclable properties. By the introduction of the CQDs with surface containing ample amide, carboxyl, and hydroxyl groups, the cross-linking networks are formed, and simultaneously, abundant H-bonds at the interface between CQDs nanospheres and PUU matrix provide strong interfacial interactions, which endows material reinforcement and self-healing effect. The addition of a very low amount of CQDs (0.15 wt%) can significantly improves the mechanical performance, especially the tensile stress and toughness, which increased about 74.4 % (35.2 MPa to 61.4 MPa) and 115.2 % (34.8 MJ·m⁻³ to 74.9 MJ·m⁻³), respectively. Besides, unlike other nanofillers, the addition of CQDs (more than 1 wt%) enables the PUU with excellent self-healing and recycling properties, and for 3 wt% addition, the room temperature self-healing efficiency can even achieve 97.0 % for 24 h without external intervention. Furthermore, the addition of the CQDs can also significantly the damping effect of the polymers. It is highly anticipated that the research will provide a facile method to construct high performance polymer materials.
Enhanced performance of polyurethane foam with presence of silica nanoparticles
2024, Composites Communications
Polyurethane foam (PUF) has been widely used in wastewater treatment, and developing such foam with improved stability is highly desirable in industry. In this study, nanocomposite foam with silica nanoparticles was developed, aiming at enhancing the thermal, chemical, and biological stability of material. FT-IR, TEM and TGA techniques were employed to study the performance of nanocomposite foam. The results showed that when the SiO₂ nanoparticles were modified by KH550 with an optimized molar ratio, the dispersion of these nanoparticles was enhanced significantly, and the developed nanocomposite foam showed much enhanced thermal stability and marginal weight loss in various chemicals. The nanocomposite foam with 3.0 wt% of nanoparticles exhibited the most significantly biochemical stability.
Composite nanofillers with a locust-like cushioned half-moon structure to improve the impact resistance of polyurethane
2023, Journal of Materials Research and Technology
Developing a highly impact absorption properties polyurethane elastomer with exceptional strength and toughness is crucial in the realm of polyurethane impact protection. Inspired by the energy dissipation structure of the soft and hard bonding in the hind limb of locusts, the paper fixed the dynamic disulphide bonds commonly found in bioproteins after hydroxy-functionalized on SiO₂ by quaternization reaction, and is creatively applied in the field of impact resistance as soft and hard sacrifice micro-regions into the polyurethane. Benefiting from the multi-scale energy dissipation approach formed by the breakage of dynamic disulphide bonds, the stress obstruction by rigid particles, and the strong bonding interface between the composite filler and the matrix, polyurethane composite have demonstrated great efficiency in energy absorption and impact protection. The static compression strength of IPS@SiO₂/PUE is 148.8% higher compared to neat PUE. Furthermore, the dynamic impact energy absorption of the composite PUE was increased by 109.36%, nearly twice that of the original polyurethane. This study proposes that this strategic approach has the potential to offer a novel method for material design, which facilitates bionic design of high-impact protective elastomers utilizing different energy dissipation mechanisms.
Strain-Hardening, impact protective and Self-Healing supramolecular polyurethane nanocomposites enabled by quadruple H-Bonding, disulfide bonds and nanoparticles
2023, Chemical Engineering Journal
Developing protective materials with intelligent and stimuli-responsive properties is indispensable for safety protection. However, combining contradictory characteristics into a single polymer is challenging, such as high mechanical strength, impact protection, and self-healing properties. Herein, a strain-hardening supramolecular polyurethane nanocomposite (SPN) with high mechanical strength and unique impact protection characteristics is synthesized by incorporating quadruple hydrogen bonds (H-bonds), disulfide bonds, and modified silica nanoparticles into polyurethane elastomer. Benefiting from the dynamic break and re-form characteristic of quadruple H-bonds and the stress dissipation behavior of nanoparticles, SPN exhibits high energy absorption efficiency and impact protection properties. During the drop ball striking test, the impact energy absorption efficiencies reached 90%, and the buffer time of impact was significantly longer than common buffering materials. The SPN exhibited excellent stretchability and self-healing ability, ascribing to disulfide metathesis and H-bonds association. Moreover, the prepared SPN could be easily processed through a hot press and showed negligible creeping. The developed SPN could serve as a novel self-standing impact protective material that offers promising prospects in sports, transportation, and aerospace fields.
Catalyzed silanization by supporting ceria on silica towards rubber composites with improved mechanical properties
2022, Composites Communications
Citation Excerpt :
In striking contrast, when ceria is supported onto silica, the agglomeration of Ce–SiO2 is observably alleviated (Fig. 3b–d). The improved silica dispersion can be interpreted by the promoted silanization in the presence of ceria, which improves the compatibility between silica and SBR [26]. In the SEM image of SBR/SiO2 composite (Fig. 3e), giant silica agglomerates are exposed on the fractured surface, suggesting poor silica dispersion and weak interfacial adhesion.
The silane modification in silica-filled rubber composites is essential to fulfil the potentials of silica. However, the silanization efficiency of silica generally remains unsatisfactory. Promoting silica silanization contributes to not only the improvements on composite properties, but also the reduction in volatile organic compound emissions during processing. In this work, we present a novel way to promote silica silanization in rubber composites by supporting ceria nanocrystals on silica surface. Specifically, silica supported with varied ceria nanocrystal loading is synthesized and used as a novel reinforcement for styrene-butadiene rubber. Model compound experiments demonstrate that the ceria on silica surface can effectively promote the silanization reaction based on its unique acid-base property. Due to the promoted silica silanization, silica dispersion is greatly improved and interfacial interaction is remarkably enhanced in the composites. Accordingly, the resulting composites filled with ceria-anchored silica exhibit desirable improvements on the tensile modulus and dynamic mechanical properties, which is conductive to tire application.
A composite nanofiller with a nail column void structure to imitate beetle shell fiber to enhance the impact resistance of polyurethane elastomer
2022, Composites Science and Technology
Citation Excerpt :
Although PUE has been widely used for daily human protection, its softening and cracking under high-speed impact has not been solved, which limits its application in high-speed impact protection [1]. To make PUE meet the requirements of high-speed impact protection, the study of PUE mechanical property enhancement has become more and more extensive and in-depth [4]. Nature has formed the basis of materials during the evolutionary process.
Polyurethane elastomer (PUE) is faced with cracking problems under the high-speed impact to limit its application in the protective field. Inspired by a “nail columns"—"nail columns” void structure of chitin fiber on the beetle shell, tetra vinyl polyhedral oligomeric silsesquioxanes (EVPOSS) composite multiwalled carbon nanotube (MCNTs) enhanced fillers (PDVBMC and PNHMC) were prepared by different bonding types and used to improve the impact resistance of PUE. The 1.5 wt% PDVBMC or PNHMC reinforced composite PUE exhibited simultaneous enhancements in maximum compression modulus (22.2% and 34.6%), energy absorption (40.1% and 53.7%) and storage modulus (16.5% and 30.6%). The excellent mechanical properties of composite PUE is not only attributed to the enhancement of interface strength between enhanced fillers and PUE matrix but also the bonding strength between enhanced fillers, which can be demonstrated by the differences in energy absorption, storage modulus and bonding fracture energy.

View all citing articles on Scopus

View full text

Synergistic enhancement effect of nano-SiO2 and ionic liquids on mechanical properties and impact resistance of polyurethane elastomer

Highlights

Abstract

Introduction

Section snippets

Materials

Preparation of KH570 modified SiO2

Synthesis of IL ([EOHVIm][Br])

Structure characterizations

Conclusions

CRediT authorship contribution statement

Declaration of competing interest

Acknowledgements

Mater. Sci. Eng. B-Adv.

Compos. Commun.

Mater. Today. Proc.

Appl. Surf. Sci.

Compos. Commun.

Compos. Commun.

Surf. Coat. Tech.

Colloid. Surface. A.

Compos. Commun.

Eur. Polym. J.

Polymer

Compos. Part. A-Appl. S.

Compos. Commun.

Compos. Sci. Technol.

Compos. Part. A-Appl. S.

Synergistic enhancement effect of nano-SiO₂ and ionic liquids on mechanical properties and impact resistance of polyurethane elastomer

Preparation of KH570 modified SiO₂