Thermal Deformation Properties of Dynamically Vulcanized Thermoplastic Elastomers Based on Random Polypropylene and Nitrile Butadiene Rubber

摘要

The thermal deformation properties of dynamically vulcanized thermoplastic elastomers based on random polypropylene and nitrile butadiene rubber (NBR) are studied. Exxelor PO1200, a graft polypropylene copolymer with a maleic anhydride, was used as a compatibilizer to improve the compatibility of polymer mixtures. The concentration of maleic anhydride in the grafted copolymer was 3.0 wt %. We showed that it is possible to improve the compatibility of bipolar mixtures through the incorporation of a compatibilizer, when there is no separation between the components of the mixture. We found that the polymer composition exhibits the properties of thermoplastic elastomers upon the introduction of 30 wt % NBR-18 and 40 wt % NBR?26 or NBR-40 into random polypropylene, so that the plastic deformation changes to a highly elastic one typical of rubbers. The temperature regions of the solid, highly elastic, and viscous-flow states are found. The polymer mixtures were vulcanized with crosslinking agents (dicumyl peroxide and sulfur) to exhibit the properties of rubber. We showed that the thermomechanical properties of dynamically vulcanized thermoplastic elastomers change significantly with an increase in concentration of dicumyl peroxide from 0.25 to 1.0 wt %. The vulcanized materials almost completely lose their ability to flow, and they transform from a highly elastic state to a glassy one after the introduction of 1.0 wt % of dicumyl peroxide. The melt flow index (MFI) of vulcanized thermoplastic elastomers remains unchanged after the introduction of sulfur in an amount from 1.0 to 10 wt %.