聚丙烯/乙烯-辛烯共聚物/新型交联助剂动态硫化过程中相形态结构的演变及力学性能研究

Thermoplastic vulcanizates (TPV) combine the melt processability of the thermoplastic and mechanical properties of the conventional thermoset rubbers. In addition, these materials can be recycled easily. The combination of excellent comprehensive performance explains the fastest growing application of TPV. But during peroxide dynamical vulcanization to prepare TPV based on polypropylene (PP), the degradation of PP is serious which will deteriorate the mechanical properties of TPV. In this project, asymmetric divinyl monomers (ADM) with different type and different reactivity ratio of double bond are synthesized as new coagent for dynamically vulcanized blends of polypropylene/ethylene-octene copolymer (PP/EOC) to prepare PP/EOC TPV. The performance of the asymmetric divinyl monomers on the controlling degradation of PP, accelerating the crosslinking of EOC, in situ reactive compatibilization, increasing the adhesion between two phases and reducing size of crosslinked rubber particles are investigated. The morphology evolution of PP/EOC/ADM blends during peroxide dynamical vulcanization is studied. High performance PP/EOC TPV is prepared by the choosing of coagent, optimization of dynamic vulcanization conditions and formula design. This project provides a new method for preparing TPV with great academic value and good application prospect.

热塑性硫化橡胶（TPV）兼具热塑性塑料的加工性能和传统硫化橡胶的机械性能，且易于循环利用，已成为用量增速最快的一类热塑性弹性体。但是采用过氧化物动态硫化技术制备聚丙烯（PP）基TPV时，极易造成PP降解从而导致其力学性能大幅下降。本项目拟设计合成不同种类和不同双键活性比的非对称双烯单体（ADM），以其作为聚丙烯/乙烯-辛烯共聚物（PP/EOC）过氧化物动态硫化的新型交联助剂来制备PP/EOC TPV材料。研究该交联助剂在高效抑制PP降解、促进EOC交联、原位反应增容、增加两相界面作用力及细化橡胶颗粒等方面的作用，研究PP/EOC/ADM共混物在过氧化物动态硫化过程中相形态结构的演变过程。通过筛选非对称双烯单体、优化动态硫化工艺条件和配方设计，制备出高性能PP/EOC TPV，以拓展TPV的应用领域。本项目为高性能TPV的研制提供了一种新方法、新思路，具有重要的学术意义和良好的应用前景。

聚烯烃类热塑性硫化橡胶（TPV）是一类重要的热塑性弹性体,在其制备过程中相形态结构的演变与调控,微观结构与性能之间的关系是人们普遍关心的基本问题。由于TPV的性能与所选的塑料和橡胶密切相关，本项目选取具有优良力学性能和耐热性的聚丙烯（PP）作为塑料相，分别选取与PP具有一定的相容性的乙烯-辛烯共聚物（EOC）和三元乙丙橡胶（EPDM）作为橡胶相。首先研究了非对称双烯单体在PP熔融接枝反应过程中的调控作用，发现非对称双烯单体能够有效地控制PP的降解，促进接枝支化反应，所制备的长链支化聚丙烯具有较宽的发泡温度窗口；研究了非对称双烯单体作为交联助剂对采用动态硫化技术制备的TPV微观结构和力学性能的影响，发现非对称双烯单体能够减小橡胶相尺寸，增强两相界面作用力,显著的提高TPV的强度和刚度；此外还将非对称双烯单体用于对PP的动态硫化增韧，发现在较低弹性体用量条件下就能使PP具有较高的冲击强度，通过力学性能、流变性能和断面形貌分析表明，冲击强度的提高主要是靠降低基体的屈服强度和提高两相界面作用力来实现的。本项目所合成的非对称双烯单体在长链支化聚丙烯和高性能热塑性弹性体的制备，以及动态硫化增韧PP方面都具有良好的应用效果。