Annealing-Induced High-Heat-Resistance Stereocomplex Poly(Lactic Acid): Processing and Performance
MA Gaoqi1, YAN Wenming2,3, LI Weimin1, ZHU Ronghua1, WANG Lunhe1, TONG Minjie1, WANG Liangbo1, PAN Pengju2,3, YU Chengtao2,3
1. Zhejiang Honor Biomaterials Company Limited, Taizhou 318000, China;
2. Institute of Zhejiang University-Quzhou, Quzhou 324000, China;
3. College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310058, China
Abstract：Stereocomplex (SC) crystallization, formed from enantiomeric poly(L-lactic acid) (PLLA) and poly(D-lactic acid) (PDLA), imparts poly(lactic acid) (PLA) materials with excellent heat resistance. However, during conventional injection molding, high-molecular-weight PLLA and PDLA blends struggle to form SC crystallites, resulting in heat resistance comparable to that of pure PLLA or PDLA. This study employed a post-molding annealing method to prepare stereocomplex PLA (SC-PLA) materials featuring high SC crystallinity and superior heat resistance. The crystalline structure and thermal properties were characterized using wide-angle X-ray scattering and Vicat softening temperature testing. The results indicated that when the blending ratio of PLLA and PDLA was 1?1 (mass ratio) and the prepared sample SC-PLA50 was annealed at 190 ℃ for 30 minutes, the sample exclusively formed SC crystallites with a crystallinity of 44.8%. Its Vicat softening temperature reached 179.3 ℃, approximately three times that of amorphous PLA. To verify the practical application value of SC-PLA50, tableware samples were successfully fabricated on an industrial injection molding platform; these tableware samples exhibited outstanding heat resistance after annealing. This work provided the basis and strategy for the industrial production of SC-PLA products using conventional processing equipment.
MA Gaoqi,YAN Wenming,LI Weimin et al. Annealing-Induced High-Heat-Resistance Stereocomplex Poly(Lactic Acid): Processing and Performance[J]. Chemical Reaction Engineering and Technology, 2026, 42(2): 152-158.
