Abstract: Poly(L-lactic acid)(PLLA) is one of the most important and promising biobased and biodegradable materials. When it was widely used as packing materials, the worldwide problems of Energy Resource Crisis and “White Pollution” can be solved. Therefore, the research about PLLA was increasingly wide and deep.
Based on the melt-polycondesation process to prepare PLLA, we investigate the possibility of ring-opening polymerization of CL initiatiated by the end hydroxyl groups of PLLA. The FT-IR and 1H-NMR analysis of pure product confirmed that the end hydroxyl groups of PLLA can initiat the ring-opening polymerization of CL and the copolymer of PLLA-PCL was obtained.
We found that at the same content of CL, the color of the product was gradually improved along with the reaction took place. When the reaction time was 9 h, the molecule weight of PLLA-PCL and conversion rate of CL were highest. Therefore, the suitable reaction time is 9 h. However, at the same reaction time, the higher content of CL, the faster the product became white and the higher molecular weight. Comparing with the pure PLLA, the PLLA-PCL copolymer has better mechanical properties.
