Preparation and properties of novel fluorosilicone thermoplastic vulcanizate with cross-linking-controlled core-shell structure

A new fluorosilicone thermoplastic vulcanizate (TPV) composed of poly(vinylidene fluoride) (PVDF), silicone rubber (SR), and fluororubber (FKM) was successfully prepared through dynamic vulcanization. The morphological structure of the TPVs had core-shell elastomer particles dispersed in a continuous PVDF matrix. Furthermore, the cross-linking of core-shell structure was controlled by adopting different curing agent. The effect of cross-linking-controlled core-shell structure on the morphology, crystallization behavior, stress relaxation test, solvent-resistant properties of the obtained TPVs were investigated. It was found that the shell cross-link had a significant influence on the crystallinity of the PVDF phase. The core-shell bicross-linked TPV was found to provide the lowest rate of relaxation. An obvious stress softening phenomenon was observed in the uniaxial loading-unloading cycles in tension. The bicross-linked TPV had good solvent resistant properties. The tensile strength of the bicross-linked TPV was still 12 MPa even after immersed in butyl acetate for 48 hours.