Anomalous mechanical behavior upon recycling of poly(phenylene-ether)-based thermoplastic elastomer

Recycling of thermoplastic elastomers based on poly (phenylene ether) (PPE) was studied in detail. The quaternary blend comprising of styrene-ethylene-butylene-styrene (SEBS)/ethylene vinyl acetate (EVA)/PPE-PS (polystyrene) showed improvement in mechanical properties upon recycling, which was correlated with the formation of crosslinked network in the system. Presence of crosslinked network was confirmed by the gel content analysis. The blend components involved in the crosslinking were evaluated by gel morphology analysis. Fourier transform infrared spectroscopy revealed the chemical composition of the crosslinked gel. Crosslinking mechanism was established based on the reactivity of allylic EVA radical during recycling. Rheological study supported the notion of crosslinking upon recycling that resulted in higher storage modulus (G(I)) as a manifestation of restrained flow by network formation. On the basis of the earlier data, a reaction mechanism for crosslinking was proposed. Finally, structure-property correlation was developed through morphological, chemical, and rheological analysis to understand the anomalous enhancement in mechanical properties upon recycling.