PREPARATION AND CHARACTERIZATION OF HNBR/PA12-BASED SUPER TPVs WITH ENHANCED THERMAL STABILITY BY USING HIGHER ACRYLONITRILE CONTENT

Abstract

ABSTRACT Thermoplastic vulcanizates (TPVs) are superior classes of thermoplastic elastomers, in which dynamic vulcanization of the rubber phase takes place during melt mixing with a semicrystalline thermoplastic matrix phase at elevated temperature. TPV is characterized by processing behaviors like thermoplasticity at elevated temperature and performance properties of vulcanized rubber at ambient temperature. High-performance TPVs or super TPVs are new-generation TPVs that exhibit high heat resistance as well as excellent oil resistance properties suitable for under-the-hood automotive applications. In the present work, a new class of super TPVs based on hydrogenated acrylonitrile–butadiene rubber (HNBR) and polyamide (PA12) has been developed. TPVs of three different acrylonitrile content (ACN)–based fixed-blend ratio (70:30) of (HNBR/PA12) have been prepared by using a peroxide curative {Di-(2-tert-butyl peroxy isopropyl) benzene (DTBPIB)}. Final morphology of TPVs varies depending on the ACN content of the rubber. A TPV with the highest ACN content shows the highest level of mechanical properties as well as superior thermal stability and creep behavior compared with all other TPVs. Dynamic mechanical analysis also demonstrates that the tan δ values of all the TPVs are lower and the storage moduli are higher than the low acrylonitrile content system. Heat aging, oil aging, oil swelling, and network characterization studies have also been carried out in detail to understand the performance behavior of these super TPVs at service condition (150 °C). These TPVs are considered for potential applications in the automotive sector, especially for under-the-hood-applications.