Influence of Organoclay Content on Morphology and Properties of Poly(Lactic Acid)/Propylene-Ethylene Copolymer/Organoclay Composites

Abstract

The effects of clay surface modified with 25-30 wt% of methyl dihydroxyethyl hydrogenated tallow ammonium (Clay-DHA) on morphology, mechanical and thermal properties of poly(lactic acid) (PLA)/propylene-ethylene copolymer (PEC)/Clay-DHA composites were investigated. The phase morphology of PLA/PEC blends showed phase separation due to weak interaction between PLA and PEC phase, and the droplet size of PEC phase increased with increasing PEC content. The addition of Clay-DHA significantly improved the compatibility between PLA and PEC phases due to PEC droplet size decreased dominantly in PLA matrix, so Clay-DHA could act as an effective compatibilizer. The tensile properties found that Young’s modulus of PLA/PEC blends decreased with increasing amount PEC while the strain at break increased. The incorporation of Clay-DHA improved Young’s modulus of the blends in a range of 10-20 wt% of PEC. The thermal properties showed that the addition of PEC and Clay-DHA had no effect on the melting temperature of PLA. The degradation temperature of PLA/PEC blends was higher than that of the PLA, so PEC could improve the thermal stability of the blends.