The Effects of Blending Ratio of Poly(lactic acid)/POSS Cored Star Poly(ε-caprolactone) Biopolymers

Abstract: A8-type eight-arm star-shaped poly(e-caprolactone) (PCL) polymers with polyhedral oligomeric silsesquioxane (POSS) (SP) core having different molecular weight with different chain lengths (n=10, 20, 30, and 50 repeating units) were synthesized via arm-first approach by combination of ring-opening polymerization (ROP) and “click” chemistry reactions. The obtained polymers were then melt-blended with neat poly(lactic acid) (PLA) to improve some of the properties like toughness of PLA. These blends were prepared depending on the blend ratio (95/5 and 80/20 wt%) via utilizing laboratory scale twin-screw mini extruder to examine morphological, thermal and mechanical properties of PLA/SP composite as a function of SP and blending ratio. In addition, the PLA/SP composites containing a blend ratio of 90/10 wt% which were prepared in the previous study was used to compare with other composite having different blend ratio. The incorporation of SP polymers improved some of the mechanical properties of PLA. It was verified that SP20 (n=20) is the most proper SP-type for enhancing the mechanical behavior of PLA at a blending ratio of 90/10. Also, 1,4-phenylene diisocyanate (PDI) which was used as a commercial compatibilizer was incorporated to blends at fixed amount (%1). It is concluded that the incorporation of SP polymers into PLA matrix decreased the tensile modulus with increasing blending ratio and increased the elongation at break values in the presence of PDI.