Thermal & morphological evaluation of linear and radial SEBS- polypropylene blends

Abstract

Blending of two or even more immiscible polymers is a very useful method to obtain new polymeric materials with ordered and tailored properties. Thermoplastic elastomers (TPE's) are interesting materials for various applications, including the automotive industry, due to their excellent balance between processability and physical properties, especially using hydrogenated styrene-butadiene copolymer. In the present work, two structures of styreneethylene/buthylene-styrene (SEBS) triblock copolymer (linear and radial) were blended with polypropylene (PP) using a process aid oil. Three different SEBS-PP ratios were evaluated. Phase behavior was studied by means of differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and Scanning electron microscopy (SEM), which confirmed the formation of a single phase material. PP crystallinity was affected by SEBS structure causing a lamellar thinning of crystals. The SEM analysis shows that radial and linear structures of SEBS have different morphology.

Morphological, mechanical, and thermal properties of PP/SEBS/talc composites

“…5 The development of PP/elastomer blends is one of the most commonly used methods to overcome this problem. 1,3,6–10…”

“…Thermoplastic elastomers (TPEs) are materials that combine the typical good elastic properties of cross-linked elastomers with the melt processability of thermoplastic polymers. 10,11 Moreover, TPEs present higher service temperature and better solvent resistance than classic elastomer systems. 6 Consequently, there are many published studies on blends of PP and TPEs, such as styrene–butadiene–styrene (SBS) or styrene–ethylene–butylene–styrene (SEBS) triblock copolymers, aiming to improve the toughness of PP.…”

“…6 Consequently, there are many published studies on blends of PP and TPEs, such as styrene–butadiene–styrene (SBS) or styrene–ethylene–butylene–styrene (SEBS) triblock copolymers, aiming to improve the toughness of PP. 1,3,5–10,12–15…”

Influence of extender oil composition on flowing property, thermal stability, and morphology of styrene‐b‐ethylene‐co‐butylene‐b‐styrene copolymer/polypropylene/oil blends

“…Furthermore, noted that the T g of pure PS is about 108°C . Thus, the lower values of T gPS found in these blends proved an interaction between PS blocks with the plasticizer oil . Moreover, in Figure D, the T gPS values dropped with increasing the oil C N content was found.…”

“…The influence of SEBS structure, extender oil type, and dosage on SEBS/PP/oil blends have been studied for years. Mendienta‐García et al found that PP crystallinity decreases significantly in the blends due to the affected EB phase by the addition of oil, and the formation of an integral EB/PP phase is also confirmed; thus, only one T g can be seen for EB and PP. SEBS structure was also found to have influence on PP crystallinity decreasing.…”