Crystallization of poly(L-lactide) in the miscible poly(L-lactide)/poly(vinyl acetate) blend induced by carbon nanotubes

In this work, carbon nanotubes (CNTs) were introduced into miscible poly(L-lactide)/poly(vinyl acetate) (PLLA/PVAc) blend and the crystallization behaviors of PLLA with the presence of PVAc and CNTs are systematically discussed. The dispersion state of CNTs was characterized using scanning electron microscope, and the crystallization behaviors of PLLA in different conditions including melt crystallization and cold crystallization were comparatively investigated using polarized optical microscope, differential scanning calorimetry and wide angle X-ray diffraction. The results showed that the crystallization of PLLA was greatly restricted by PVAc. CNTs exhibit apparent nucleation effect, promoting the occurrence of both melt crystallization and cold crystallization. However, the nucleation effect of CNTs in the ternary composites is weakened as compared with that in the binary PLLA/CNTs composites. It was suggested that the relatively higher interfacial affinity between PVAc and CNTs, which possibly resulted in more PVAc molecule rather than PLLA molecule around the surface of CNTs, was the main reason for the reduced nucleation efficiency.