基于动态硫化法的PVDF基-氟硅热塑性弹性体的制备、界面增容与性能研究

Fluorosilicone rubber is an absolutely necessarily special rubber for aerospace, military industry, and related high-technology fields. It's an urgent need for us nowadays to speed up improve the preparation technical level for the fluorosilicone elastomer materials. However, the long synthetic route, complex process and high technical requirements add difficulties to the mass production; in addition, the high cost also restricts the popular application for fluorosilicone rubber. In this subject, a meltable fluoroplastic—polyvinylidene fluoride (PVDF) and methylvinyl silicone rubber (MVQ) are used to prepare PVDF-based fluorosilicone thermoplastic elastomer by dynamic vulcanization. Because of the low surface energy of PVDF, various efficient compatibilization methods are employed to improve the compatibility between PVDF matrix and MVQ phase, further improving the performance of PVDF-based fluorosilicone thermoplastic elastomer. Moreover, intensive research will be performed on the preparation, structure and properties, compatibilization of the interface, changes of structure and properties during multiple processing. At last, a“processing-structure-properties-mechanism”theory is proposed to promote the preparation of PVDF-based fluorosilicone thermoplastic elastomer with further enhanced performance, which is expected as a good potential alternative for the expensive fluorosilicone rubber. The research in this project will lay a foundation for the realization of industrialization for this kind of material, which has positive academic significance and application prospects.

氟硅橡胶是航空航天、国防工业以及有关高技术领域必不可少的特种橡胶材料，目前我国十分迫切需要加快提升制备这类材料的技术水平。然而氟硅橡胶合成路线长、工艺复杂、技术要求高，难以大规模生产，同时价格昂贵而在普及应用上受到限制。本项目拟基于动态硫化法，采用甲基乙烯基硅橡胶（MVQ）和可以熔融加工的聚偏氟乙烯（PVDF），通过有效的增容改性手段提升PVDF基体与MVQ的界面相容性，制备PVDF基-氟硅热塑性弹性体，将氟材料、硅橡胶的优点进行有机结合。系统深入地研究其制备、结构与性能、界面增容改性、重复加工过程中的结构与性能变化等，最终获得“加工条件-结构-性能-机理”的理论，进而指导动态硫化法制备性能优良的PVDF基-氟硅热塑性弹性体，在一定范围内部分替代氟硅橡胶。本项目的工作为实现这类材料的工业化奠定基础，具有积极地学术意义和应用前景。

本项目中，我们采用动态硫化技术，以甲基乙烯基硅橡胶（SR）和聚偏氟乙烯（PVDF）为主材料，通过有效的增容改性手段提升PVDF基体与SR的界面相容性，成功制备了PVDF基-氟硅热塑性硫化胶（TPV）。我们对温度、转速以及时间等加工因素对动态硫化的影响进行了系统研究，从橡胶相的交联速率与破碎速率的匹配关键性问题对交联橡胶粒子的尺寸和分布进行调控，并建立了模型分析。研究发现，PVDF与SR界面相容性差而导致橡胶相含量超过50wt%时，动态硫化不能顺利进行，产物成粉状，无热塑加工性能。即使以塑料相为主时，动态硫化产物的力学性能较低而无使用价值。对此，我们利用甲基丙烯酸锌（ZDMA）在过氧化物引发下发生聚合反应、氟硅橡胶（FSR）作为界面增容剂以及丁腈橡胶（NBR）作为第三组分橡胶调控橡胶相结构三种途径，改善PVDF塑料相与SR橡胶相的界面相容性，有效提高动态硫化TPV材料的力学性能。我们还对TPV的结构与性能、重复加工型进行了研究，获得“加工条件-结构-性能-机理”的机理关系，所获得的TPV力学性能接近市面上的一些氟硅橡胶。