Effects of Poly(D-lactide acid) on the Properties of Crystallization and Thermal Behavior of Poly(L-lactide acid)

Abstract

In order to improve the heat deflection temperature and ability of crystallization of poly(L-lactic acid) (PLLA) based materials, Poly (D-lactic acid) (PDLA) was used to complex with PLLA to form a stereocomplex. The effects of annealed time and different amounts of poly(D-lactic acid) (PDLA) on the crystallization, thermal behavior and mechanical properties of poly(L-lactic acid) (PLLA) were investigated by differential scanning calorimeter (DSC), X-ray diffraction (XRD), polarized optical microscopy (POM) ,et al. The results indicated that the PDLA was an effective nucleating agent for PLLA. A higher density of the stereocomplex crystallites was consistent with the increased content of the PDLA and annealed time. Samples that PLLA complexed with PDLA have the fastest crystallization rate at 393 K. The complexed materials have high heat deflection temperature (HDT), high Tm, high crystallinity and crystallization rate. With the annealed time and PDLA content in PLLA matrix increased, the tensile strength, modulus and elongation-at-break of the PLLA increased.