Inhibition of degradation in styrene-based thermoplastic elastomers by hydrogen-donating hydrocarbons

Abstract

The effects of hydrogen-donating hydrocarbon additives derived from petroleum (HHAPs) on styrene-based thermoplastic elastomers, styrene-butadiene-styrene (SBS) and styrene-isoprene-styrene (SIS), during mixing at 180°C in air were investigated and the following results were obtained: 1. (1) Changes in torque, temperature, gel fraction, mechanical properties and molecular weight distribution were investigated for SBS (crosslinking is the main cause of degradation), and mechanical properties and molecular weight distribution were studied for SIS (scissions are the main cause of degradation). 2. (2) The obvious effects against these types of degradation can be attributed to the high radical scavenging abilities of the additives. Thus, the inhibiting effects correspond precisely to the reaction rates with DPPH (2,2-diphenyl-1-picrylhydrazyl). HHAPs are new conceptual inhibitors because of their pure hydrocarbon constituents without functional groups containing heteroatoms, and they are interesting enough to be investigated further.