Characterization and mechanical properties of poly(lactic acid)/poly(ϵ‐caprolactone)/organoclay nanocomposites prepared by melt compounding

Abstract This study investigates the preparation, characterization, and mechanical properties of nanocomposites prepared from poly(lactic acid) (PLA), an organoclay, hereafter referred to as Clay, and poly(ε‐caprolactone) (PCL) by melt compounding in a co‐rotating type, twin screw extruder. The molecular weight of the PCL used was 10K, 40K, or 70–100K. Tensile test data show that the Young's modulus of the PLA/Clay nanocomposite was about 19% higher than that of neat PLA. The tensile strength of the PLA/PCL(10K and 40K)/Clay nanocomposites was about 17% higher than that of neat PLA. On the other hand, the tensile strength of the PLA/PCL(70–100K)/Clay sample was about 7% lower than that of neat PLA. The elongation of the PLA/PCL/Clay composite also improved. The effect of d‐spacing, resulting from adding PCL to the PLA/Clay nanocomposite, depends on the molecular weight of the PCL. The size of the clay agglomerates in the PLA/PCL/Clay nanocomposites is larger than those found in the PLA/Clay. Furthermore, the thermal stability of the PLA/Clay nanocomposite increases with the addition of PCL. On the whole, PCL(10K) was found to be the best additive for PLA/Clay nanocomposites. POLYM. ENG. SCI. 46:1001–1007, 2006. © 2006 Society of Plastics Engineers