JOURNAL OF POLYMER SCIENCE
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2021
·Vol. 59
·期 13
·1390-1398
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IF 0
Yaochen Zheng,Peng Song,Shaoxiang Liu,Mengqing Wu,Hui Xu,Chenghui Qiao,Jian Liu,Zhengguo Gao,Qingfu Ban
Spiroacetal moieties containing linear telechelic polymers (LTPs) with two terminal epoxy groups were facilely synthesized via the successive thiol-ene and thiol-epoxy click additions. The LTPs were incorporated into epoxy matrix to fabricate the transparent and toughening thermosets. In term of the miscibility of epoxy with the adduct of ethanedithiol and 3,9-divinyl-2,4,8,10-tetraoxaspiro[5.5]undecane (BTU), it is proposed that the size of the formed nanostructures was small enough to allow light penetrate. Therefore, the modified thermosets were transparent, which was further confirmed by small-angle X-ray scattering (SAXS) measurements. The LTPs with an alternating structure of rigid spiroacetal moiety and soft thioether could formed heterogeneous crosslinked networks (HCNs) and obviously toughen epoxy thermosets. Flexural strength increased from 1.06 GPa for neat epoxy to 2.09 GPa for toughening thermosets modified with 15 wt% LTPs. The stress field intensity ( K IC ) value reached up to 3.93 by more than 125% compared with that of the control sample (1.75). This work uncovered the role of HCNs on performance and paved a way for technological advances toward transparent and toughening materials in epoxy thermosets. Graphical
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
MACROMOLECULES
·
2021
·
IF 5.985
Chengfeng Zhang,Xinglong An,Zhenghai Tang,Shifeng Fang,Baochun Guo,Liqun Zhang,Fang Liu,Junjie Liu,Zhiquan Chen
High-performance rubbers with low gas permeability have attracted extensive attention due to their wide application. In this work, for the first time, the tortuosity effect is created in unfilled rubbers via heterogeneous cross-linking. The heterogeneously cross-linked rubbers exhibit a sea–island morphology with excellent interfacial interactions in which the dispersed rubber granules (RGs) are densely cross-linked, while the matrix phase is normally cross-linked. The hard RG phases showed low gas permeability, which can not only serve as a rigid yet elastic reinforcement for rubbers but also inhibit the gas permeation in rubbers. The excellent interfacial interactions between the two phases have a pronounced effect on the ultimate performance of rubbers. Surprisingly, the simultaneously improved mechanical performance and the gas barrier property achieved in the heterogeneously cross-linked rubber are competitive with the rubber nanocomposites filled with two-dimensional fillers. It is revealed that the ingenuity of such a heterogeneous design is the tortuosity effect imposed by the dispersed RG phases with low permeability, which makes an additional contribution to the reduction of gas permeability. Accordingly, a modified Nielsen equation was developed to model the gas barrier property of heterogeneously cross-linked rubbers, offering reliable prediction and rational mechanism elucidation of gas permeation for the heterogeneous design. In view of the scale-up capability and universality of this method, we envisage that this work offers a promising avenue, alternative to nanofilling, for preparing the rubbers with excellent gas barrier properties.
研究领域:
材料科学
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高分子化学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS SCIENCE FORUM
·
2018
·
IF 0
Rui Min Zhao,Xian Ya Xue,You Fa Wang
Porous Hyaluronan/β-tricalcium phosphate composite scaffolds were synthesized through lyophilizing and subsequent heterogeneous crosslinking method. The morphology of the composite scaffolds were investigated by scanning electron microscopy (SEM). The swelling behavior, mechanical property, degradation behavior and cell adhesion ability of samples were also studied. The results revealed that hyaluronan mainly contributed to the polymer matrix and water adsorption, whereas β-TCP acted as a reinforcement to strengthen the porous structure, while too much β-TCP would make the structure collapse. The pose size of obtained scaffolds ranges from100μm to 200μm and the porosity decreased with the increase of β-TCP content. The degradation behavior and cell adhesion test indicated that increasing hyaluronan concentration can effectively improve the degradability of scaffolds and the incorporation of β-TCP improved the cell adhesion performance. Thus a simple way to prepare hyaluronan-based composite scaffolds was provided, which could be potentially used as an tissue engineering material.
研究领域:
生物材料
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组织工程
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生物医学工程
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产品关联
DOI
Polymer Chemistry
·
2021
·Vol. 13
·期 6
·829-837
·
IF 5.582
Xiaowei Xu,Xinyue Hao,Jing Hu,Weisheng Gao,Nanying Ning,Bing Yu,Liqun Zhang,Ming Tian
Silicone rubber is a type of elastomer that possesses excellent biocompatibility and a good resistance to high and low temperatures and can be used as the matrix of smart materials in the biomedical field. As one of the attractive functions of smart materials, their regional shape transformation behavior under multiple stimuli is very useful. In order to produce silicone elastomers with these characteristics, a special structure such as a Janus structure is usually required. Herein, a novel strategy to prepare a silicone elastic light-triggered actuator with a Janus structure has been developed, which was fabricated via heterogeneous crosslinking induced by a gradient intensity of UV light due to carbon nanotube (CNT) accretion. By tailoring the geometric shapes, the region and time of the UV irradiation and the location of the stimulus, the Janus membranes can be programmed with multiple types of deformations and exhibit a shape transformation triggered by organic solvent or laser irradiation. Additionally, the membrane can be readily switched between Janus and homogeneous structures due to the reversible dimerization of anthracene, resulting in the reconfiguration of the membrane. Meanwhile, the composite membrane exhibits an excellent self-healing ability at 60 °C, or even room temperature, and can be recycled repeatedly via the hot-pressing or solution casting methods because of the introduction of reversible imine bonds into the crosslinked networks. This strategy provides significant guidance for the design of self-healable and reconfigurable soft biocompatible actuators, and so forth.
研究领域:
材料科学
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生物医学工程
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纳米技术
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智能材料
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）