【摘要】 以L-乳酸单体为原料,用逐步减压缩聚法合成了相对高分子量的聚乳酸。探讨了反应条件如:温度、反应时间、催化剂用量、酯化时间、逐步减压时间等对聚乳酸分子量的影响,并采用FTIR1、H NMR测试手段对聚合物进行了结构表征。结果表明,催化剂用量为0.5wt%,反应温度180℃,先酯化7小时,再逐步减压7小时,然后在高真空度70Pa下反应45小时,可得到重均分子量约为12万的聚乳酸。更多还原

【Abstract】 The relative high molecular weight poly（L-lactic acid）（PLLA） was synthesized through the melt polycondensation of L-lactic acid with reducing the reaction pressure step by step.The effects of temperature,time of reaction,amount of catalyst,time of esterifying,time of decompression step by step,etc, on molecular weight of PLA were studied.FTIR（Fourier transform infrared） and （）¹H NMR（nuclear magnetic resonance） were used to characterize the PLLA.The results indicate that the molecular weight of PLLA was up to 12×10⁴ under an optimum reaction condition as following: LA was esterified for 7 hours,and decompressed to 40-70Pa for 7 hours,then polycondensed for 45 hours and the whole reaction was carried out at 180℃ and amount of catalyst was 5wt%.更多还原