Quantifying microstructural, thermal, mechanical and solid-state viscoelastic properties of polyolefin blend type thermoplastic elastomer compounds

In this study, polyolefin blend type thermoplastic elastomer compounds were prepared via melt blending method in a twin screw extruder by using isotactic polypropylene (i-PP) as thermoplastic matrix, three different styrene-olefin triblock copolymers (SEBS-1 and SEBS-2 having styrene contents of 30 wt% and 60 wt%, respectively and SEEPS having a styrene content of 30 wt%) as elastomer phase and paraffinic oil as plasticizer. Microstructural, morphological, thermal, mechanical, and solid-state viscoelastic properties of compounds were investigated with SEM, XRD, DSC, DMA methods, and tensile tests depending on structural difference of elastomer phase and compositional variations. It was found that styrene content of elastomeric component govern physical properties of compounds and higher styrene content lead to increase immiscibility between thermoplastic and elastomer phases. It can be concluded that elastomer amount into composition dramatically affects the short-term mechanical properties of compounds such as elastic modulus, yield stress, and yield strain while elastomer type does not influence such properties, significantly. On the other hand, elastomer type, specifically hard segment content, possess a great effect on long-term physical performances of compounds. [Display omitted] •Blend type polyolefin TPE compounds were prepared by using PP, SEBS, SEEPS and paraffinic oil.•Effects of styrene-olefin block copolymer structure on the compound properties were quantified.•Styrene content of SEBS or SEEPS governs the long-term mechanical performances of TPEs.