Enhancement of the tensile retraction properties of a styrenic block copolymer by melt blending with PA6

摘要

Styrene-ethylene-propylene-styrene triblock copolymer (SEPS), a thermoplastic elastomer (TPE) was blended with polyamide-6 (PA6) in an attempt to improve the retraction properties of the TPE. A maximum loading of 30 wt % of polyamide was incorporated into SEPS using twin-screw compounding. Various reactive compatibilisers were also incorporated at a maximum loading of 10 wt %. The blends were evaluated in terms of their tensile, dynamic mechanical, and rheological behavior. Design of experiments (DOE) was used to study the effect of blending variables on the tensile properties of the blends. Complex interactions between these variables were identified using this approach. It was shown that by incorporating PA6 into SEPS, in conjunction with a compatibilizer, blends with superior retraction properties and increased tensile strength could be obtained. A mean hysteresis of 54.2 ± 0.7% was recorded for a blend containing 5 wt % PA6 and 4 wt % compatibilizer compared to 58.5 ± 0.5% for virgin SEPS. The tensile strength of this blend was almost 75% higher than virgin SEPS. Further evidence of the benefit of incorporating a reactive compatibilizer was the absence of a distinct polyamide relaxation in the dynamic mechanical thermograms for the compatibilized blends.