乙丙橡胶共聚物的^(13)C—NMR研究

^(13)C-NMR STUDY OF ETHYLENE - PROPYLENE COPOLYMERS

用溶剂CCl_4,在室温(22℃)条件下,对三种乙丙橡胶共聚物进行^(13)C-NMR测定,得到分辨率较高的图谱,标识了各种类型C原子,确定了共聚单体组成和序列分布。结果表明,样品A、B具有嵌段丙烯和嵌段乙烯序列结构可能性较大,样品C具有交替丙烯-乙烯-丙烯序列的倾向较大。用两种统计模型对三个样品的三元组分布进行处理来推测聚合反应机理。

Three ethylene-propylene copolymers were investigated by 13C-NMR in an ordinary solvent (CCl4) and at room temperature (22℃). For the present measurements, the resolution was higher and peaks were assigned comonomcr compositions and sequence distributions of these copolymers were quantitatively determined. The results show that samples A, B have sequence structures of block propylene and block ethylene mostly while Sample C has a tendency toward alternating propylene-ethylene -propylene sequences. Two statistical models were used to deduce the mechanism of polymerization process.