Synthesis and Stereocomplex Crystallization of Poly(lactide)-Graphene Oxide Nanocomposites

Poly(lactide) (PLA)-graphene oxide (GO) nanocomposites were prepared by blending commercial poly(l-lactide) (PLLA) with GO-g-PDLA, where GO-g-PDLA was synthesized via ring-opening polymerization using modified GO as the initiator. Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) studies showed that a stereocomplex crystal could be formed between PLLA and GO-g-PDLA. The incorporation of GO nanofillers leads to a lower crystallization activation energy of stereocomplex and a higher crystallinity in solution casting samples, mainly due to the heterogeneous nucleating effect of the well-dispersed covalently bonded GO sheets, while in cold crystallized samples, the crystallinity was low owing to exfoliated GO sheets which may reduce chain mobility and hinder crystal growth.