Synthesis, stereocomplex crystallization, morphology and mechanical property of poly(lactide)–carbon nanotube nanocomposites

Poly(lactide) (PLA)–carbon nanotubes (CNTs) stereocomplex nanocomposites were prepared by blending of commercial poly(L-lactide) (PLLA) and CNT-g-poly(D-lactide) (CNT-g-PDLA), where CNT-g-PDLA was synthesized via ring-opening polymerization initiated by modified CNTs. FT-IR, DSC, and XRD studies showed that stereocomplex crystallites could be formed between the PLLA matrix and CNT-g-PDLA. The incorporation of CNTs leads to a lower crystallization activation energy and an enhanced crystallinity in solution-casting samples. This is mainly due to the heterogeneous nucleating effect of CNTs, as demonstrated by TEM study which shows the existing of stereocomplex crystallization possibly initiated by CNTs. The homogeneous dispersion of CNTs and the formation of a stereocomplex between CNT-g-PDLA and PLLA lead to a better mechanical properties of the resulting nanocomposites.