【摘要】 以D,L 乳酸为单体、氧化锌为催化剂,使乳酸先缩聚后解聚制备了D,L 丙交酯;再以辛酸亚锡为催化剂,使丙交酯单体开环本体聚合制备了聚乳酸。考察了乳酸脱水温度、氧化锌用量对丙交酯收率的影响;考察了聚合温度、辛酸亚锡用量对聚乳酸相对分子质量的影响;用红外光谱(IR)、核磁共振光谱(1H NMR)对丙交酯及聚乳酸的结构进行了表征。结果表明,乳酸在130℃、氧化锌质量分数为1.3%时,仅用3h就可制得丙交酯,且其收率大于24%;丙交酯聚合时,当n(单体)/n(辛酸亚锡)=5000、聚合温度在160℃时,常压聚合5h即可得到粘均分子质量为6.3×104的聚乳酸;IR、1H NMR测试结果表明环状丙交酯在辛酸亚锡催化剂作用下发生了开环反应。聚乳酸在氢氧化钠水溶液中降解实验表明,聚乳酸具有很好的降解性,在碱溶液中降解速度较快。更多还原

【Abstract】 The poly(D,L-lactide)(PLA) was synthesized from D,L-lactide(LA) by bulk ring-opening polymerization with the stannous octoate as the catalyst. The effect of temperature, quantity of ZnO on the yield of lactide, the relationship between the temperature of polymerization, catalyst content and the relative molecular weights of PLA were discussed in detail. The lactide and the polylactide were characterized by infrared spectroscopy(IR) and nuclear magnetic resonance(~1H-NMR). The degradation of PLA has been investigated in 0.01mol/L NaOH solution. The results showed that the synthetic methods of the LA and PLA are simple and effective and the yield of LA preponderated over 24% within 3 hours and the Mv of PLA which was polymerized within 5 hours under the normal pressure reached 6.3×10~4.更多还原