Authors: ZhaoYang Wang YuFen Luo RuiRong Ye XiuMei Song
Publish Date: 2010/04/28
Volume: 18, Issue: 4, Pages: 499-508
Abstract
Directly starting from lactic acid LA and trimesic acid TMA novel biodegradable material polylactic acidtrimesic acid PLT a modified polylactic acid PLA with terminal carboxyl was synthesized via melt copolycondensation The optimal synthetic conditions including catalyst kinds and dosage prepolymerization time copolymerization temperature and time were discussed When Llactic acid LLA and TMA as molar feed ratio nLLA/nTMA 120/1 was prepolymerized for 8 h at 140 °C the copolycondensation catalyzed by 09 wt SnCl2 at 190 °C for 8 h gave PLT with the biggest intrinsic viscosity η 191 dL∙g−1 and the corresponding weightaverage molecular weight Mw was 14100 Da Serial LPLTs at different molar feed ratios were synthesized and characterized with FTIR 1H NMR GPC DSC and XRD Increasing nLLA Mw increased first and the biggest Mw was 17500 Da at nLLA/ nTMA 240/1 then decreased Using DLlactic acid DLLA instead of LLA the influences of LA stereochemical configuration were investigated The peak phenomenon of Mw was similar but the biggest Mw was 23100 Da at nDLLA/nTMA 320/1 The serial LPLTs had a certain crystallinity 102∼230 while all DLPLTs were amorphous These differences may be in touch with the reaction mechanism of direct melt copolycondensation The method was simple and practical for the synthesis of PLA biomedical materials applied in drug delivery carrier and vessel substitution material
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