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An Interfacial Dynamic Crosslinking Approach toward Catalyst-free and Mechanically Robust Elastomeric Vitrimer with a Segregated Structure
Chinese Journal of Polymer Science ( IF 4.3 ) Pub Date : 2020-09-02 , DOI: 10.1007/s10118-020-2479-6
Yong Zhu , Jing-Li Gao , Lin-Jun Zhang , Yan Peng , Hao Wang , Fang-Wei Ling , Guang-Su Huang , Jin-Rong Wu

Elastomeric vitrimers with covalent adaptable networks are promising candidates to overcome the intrinsic drawbacks of conventional covalently-crosslinked elastomers; however, most elastomeric vitrimers show poor mechanical properties and require the addition of exogenous catalysts. Herein, we fabricate a catalyst-free and mechanically robust elastomeric vitrimer by constructing a segregated structure of sodium alginate (SA) in the continuous matrix of epoxidized natural rubber (ENR), and further crosslinking the composite by exchangeable hydroxyl ester bonds at the ENR-SA interfaces. The manufacturing process of the elastomeric vitrimer is facile and environmentally friendly without hazardous solvents or exogenous catalysts, as the abundant hydroxyl groups of the segregated SA phase can act as catalyst to activate the crosslinking reaction and promote the dynamic transesterification reaction. Interestingly, the segregated SA structure bears most of the load owing to its high modulus and small deformability, and thus ruptures preferentially upon deformation, leading to efficient energy dissipation. Moreover, the periodic stiffness fluctuation between rigid segregated SA phase and soft ENR matrix is beneficial to the crack-resisting. As a result, the elastomeric vitrimer manifests exceptional combination of catalyst-free, defect-tolerance, high tensile strength and toughness. In addition, the elastomeric vitrimer also exhibits multi-shape memory behavior which may further broaden its applications.



中文翻译:

界面动力学交联方法分离结构的无催化剂和机械稳健的弹性体微粉化剂

具有共价适应性网络的弹性体三聚物是有望克服常规共价交联弹性体固有缺点的有前途的候选者。然而,大多数弹性体微粉显示出较差的机械性能,并且需要添加外源催化剂。本文中,我们通过在环氧化天然橡胶(ENR)的连续基质中构建海藻酸钠(SA)的隔离结构,并通过在ENR-处通过可交换的羟基酯键进一步交联复合物,来制造无催化剂且机械强度高的弹性体vitrimer。 SA接口。弹性体修磨剂的制造过程简便易行,对环境无害,无有害溶剂或外源催化剂,因为分离出的SA相中丰富的羟基可以充当催化剂来激活交联反应并促进动态酯交换反应。有趣的是,分离的SA结构由于其高模量和较小的可变形性而承担了大部分载荷,因此在变形时会优先破裂,从而导致有效的能量消散。此外,刚性偏析SA相与软ENR基体之间的周期性刚度波动有利于抗裂。结果,弹性体修磨剂表现出无催化剂,耐缺陷,高拉伸强度和韧性的优异组合。另外,弹性体修磨剂还表现出多种形状的记忆行为,这可进一步拓宽其用途。分离的SA结构由于其高模量和较小的可变形性而承担了大部分载荷,因此在变形时会优先破裂,从而导致有效的能量消散。此外,刚性偏析SA相与软ENR基体之间的周期性刚度波动有利于抗裂。结果,弹性体修磨剂表现出无催化剂,耐缺陷性,高拉伸强度和韧性的优异组合。另外,弹性体修磨剂还表现出多种形状的记忆行为,这可进一步拓宽其用途。分离的SA结构由于其高模量和较小的可变形性而承担了大部分载荷,因此在变形时会优先破裂,从而导致有效的能量消散。此外,刚性偏析SA相与软ENR基体之间的周期性刚度波动有利于抗裂。结果,弹性体修磨剂表现出无催化剂,耐缺陷,高拉伸强度和韧性的优异组合。另外,弹性体修磨剂还表现出多种形状的记忆行为,这可进一步拓宽其用途。刚性偏析SA相与软ENR基体之间的周期性刚度波动有利于抗裂。结果,弹性体修磨剂表现出无催化剂,耐缺陷,高拉伸强度和韧性的优异组合。另外,弹性体修磨剂还表现出多种形状的记忆行为,这可进一步拓宽其用途。刚性偏析SA相与软ENR基体之间的周期性刚度波动有利于抗裂。结果,弹性体修磨剂表现出无催化剂,耐缺陷,高拉伸强度和韧性的优异组合。另外,弹性体修磨剂还表现出多种形状的记忆行为,这可进一步拓宽其用途。

更新日期:2020-09-05
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