聚乳酸单体-丙交酯的合成

Synthesis of PLA monomer-D,L-polylactide

以D,L-乳酸为单体,无水氧化锌(ZnO)为催化剂,低真空条件下乳酸先缩聚后解聚制备了D,L-丙交酯。考察了脱水温度、脱水率、催化剂用量、解聚温度对丙交酯产率的影响。改进丙交酯的提纯方法,提高了丙交酯的重结晶收率。毛细管熔点法测定了产物的熔点,并用红外光谱、差示扫描量热法、X-射线衍射分析对产物进行了分析表征。结果表明,所得产物为高纯的环状丙交酯。

D,L-lactide was prepared from D,L-lactic acid with zinc oxide as catalyst by means of polymerization and depolymerization at low vacuum level condition. Effects of dehydration temperature, ratio of dehydration, catalyst quantity as well as depolymerization temperature on yield of lactide were studied. The collection ratio of recrystallization was improved by improving the method of purification. Melting point of product was measured by capillary tube method and the ring lactide of high purity was identified by infrared spectroscopy（IR）, differential scanning calorimetry（DSC）, X-ray diffraction（XRD）.