A high-performance temperature sensitive TPV/CB elastomeric composite with balanced electrical and mechanical properties via PF-induced dynamic vulcanization

Abstract

A conductive elastomeric composite of carbon black (CB) filled thermoplastic vulcanizate (TPV) based on polypropylene (PP)/ethylene-propylene-diene rubber (EPDM) blends was fabricated via phenolic resin (PF)-induced dynamic vulcanization in an effort to prepare temperature sensitive elastomeric materials with balanced properties. Fourier transformed infrared spectroscopy and gel content analysis revealed that the EPDM was effectively cured by PF and the degree of crosslinking reached 38.7 wt%. Morphology observation revealed that CB particles distributed in the EPDM phase in uncrosslinked thermoplastic elastomer composites, whereas CB particles were almost completely located in the PP matrix in TPV composites. For TPV composites, the morphological characteristic combined the temperature sensing properties of the PP/CB composite with the excellent resilience of the cured EPDM phase, resulting in an excellent balance in electrical and mechanical properties. Compared with the contrast composite, the TPV composite showed the lowest percolation threshold of electrical conductivity, significant enhancement of tensile stress at 300% stretching, ultralow negative temperature coefficient (NTC) effect, outstanding positive temperature coefficient (PTC) effect and repeatability. This study offers an example of high-performance temperature sensitive elastomeric materials with balanced properties.