Environmental-Friendly Catalyzed Synthesis of Poly(lactic acid-co-citric acid) by Macro Resin Solid Acid Using Direct Melt Polycondensation

In order to prepare a new material with good biocompatibility, poly(lactic acid)-citric acid (PLCA) copolymer was prepared by direct copolymerization using macroporous resin as catalyst. Experimental comparison of the catalytic properties of different types of macroporous resin-Amberlyst (A), the order of the catalytic efficiency is: A-70 > A-15 > A-35 > A-36, the main cause of the catalytic performance difference is the proportion of different resin halogen element content is different, and heat resistance performance of different catalysts. The copolymerized products were analyzed by IR, NMR, XRD, and DSC, respectively. The preparation of poly(lactic acid), citric acid copolymer PLCA crystal configurations and poly(L-lactic acid) (PLLA) are similar, but the crystallinity and heat temperature slightly lower than that of PLLA, and heat resistance, the crystallinity of the same type of PLCA were positively correlated, high crystallinity, is its high heat resistance.