基于原位界面增容构建具有典型“海-岛”结构的PP/EPDM热塑性硫化胶形状记忆效应的研究

To develop new functional application for a traditional material has stronger time effectiveness and applicability than to create a completely new material. For a long time, shape memory polymers (SMPs) have been popular materials in the field of functional application that the unique “memorizing” ability brings them potential applications in smart medical devices, heat shrink packaging, sensors, intelligent fabric and self-unfolding solar battery panels. PP/EPDM thermoplastic vulcanizate (TPV) meets the requirement of heat-triggered SMPs well in material composition. However, its rubber/plastic interface may be easily ruptured during deformation due to its sea-island structure in which the crosslinked rubber particles and plastic continuous phase are an immiscible system. As a result, PP/EPDM TPV lost its ability to construct the shape memory effect. In this project, constructing shape memory effect of PP/EPDM TPV is realized via the effectively in-situ compatibilization by metallic salts of unsaturated carboxylate. Structure control and optimization of implementing procedure are employed to further strengthen the shape memory effect of TPV. The relationship between plastic continuous phase, compatibilized interface and crosslinked rubber particles during shape memory behavior is also explored and discussed in this project. The project of developing new functional applications for PP/EPDM TPV has economical significance and social benefit. It will enrich the technique of dynamic vulcanization to prepare SMPs and offer demonstration effect and incentive action for the development of traditional materials.

传统材料新功能应用的开发相对于前沿新材料的研究更具成果转化的时效性与应用性。形状记忆聚合物（SMPs）多年来一直为功能应用研究领域的前沿热点，在医疗器械、包装、传感器、智能纺织品和自展开太阳能帆板等领域极具应用前景。我们前期研究发现，PP/EPDM热塑性硫化胶（TPV）在材料组成上很好满足热响应型SMPs的物性要求，但塑料相与交联橡胶粒子形成的“海-岛”结构在形变中橡塑界面易被破坏而散失TPV构建形状记忆的能力。本课题以PP/EPDM为蓝本体系，在动态硫化过程中通过不饱和羧酸金属盐切实有效的原位反应增容解决上述问题，构建TPV形状记忆效应。通过结构调控与实施程序调控强化形状记忆效应，阐明塑料连续相、增容界面、交联橡胶粒子在形状记忆行为中的机制关系。项目对PP/EPDM TPV新功能应用的开发具有较高的经济价值和社会效益，将丰富动态硫化制备形状记忆材料，对传统材料的发展具有示范与激励作用。

本项目中，我们以PP/EPDM TPV为研究体系，过氧化物引发动态硫化，通过不饱和羧酸金属盐聚合反应增容获得支持与实施形状记忆行为的增强相界面，成功构建TPV的形状记忆行为。不饱和羧酸金属盐原位增容，切实有效地提升了TPV的力学性能。基于此，我们还拓展了塑料相为主的TPV增韧/增强的均衡研究，成功获得冲击强度与拉伸强度同步提升的TPV材料。同时，我们对PP连续相、增强界面以及交联橡胶粒子在形状记忆行为中的相互作用进行了研究，探索形状记忆行为程序的调控对形状记忆效应的影响，阐明了TPV通过增强界面实现形状记忆的机理，并建立了 “加工-结构-性能-机理”的关系机制，为动态硫化制备橡塑共混形状记忆材料提供理论基础和实验依据。