【摘要】 以无毒性的二丁基镁为催化剂催化β-丁内酯和ε-己内酯本体开环共聚合,制备了一系列不同单体配比的共聚物。核磁共振碳谱分析了共聚物微观结构,计算了各单元平均序列长度,共聚物组成显著影响单元序列长度。酯交换反应使得单元序列结构重新分布并趋向于无规分布,但没有达到完全无规化分布。差示扫描量热仪和X射线衍射仪分析了共聚物的热性能和结晶性,表明共聚物热性能和结晶性依赖于共聚物组成和单元序列长度。更多还原

【Abstract】 A series of copolymers with various compositions were prepared by the ring opening copolymerization of β-butyrolactone and ε-caprolactone using nontoxic dibutylmagnesium as catalyst in bulk. The chain microstructure analyses of the obtained copolymers were performed by nuclear magnetic resonance (13C-NMR). The carbonyl carbon signals in 13C-NMR are the most sensitive to the sequence distributions of the butyroyl and caproyl units and used for calculating their sequences length. The copolymer composition has a profound influence on the average block length of comonomer units. Transesterifications occurred during polymerization process and played an important role in the redistribution of comonome sequences but not a completely random distribution. The thermal properties and crystallinity of the obtained copolymers were investigated by differential scanning calorimetry and X-ray diffraction. The thermal properties and crystallinity greatly depend on both the composition and the chain microstructure.更多还原