新型高效催化剂乙烯/1-丁烯气相齐聚和共聚制备弹性体及其结构与性能关系

用新型催化体系TiCl₄,Ti(OBu)₄/MgCl₂,SiO₂和ZnCl₂/醇/AlR₃催化乙烯与1-丁烯气相均聚及共聚,制得两种共聚物弹性体,发现新型催化剂体系具有独特的齐聚和原位共聚性能.采用¹³CNMR测定了共聚物链序列分布结构,观察到共聚单体在聚合物链中分布不均匀,存在较长的乙烯链段和较多的1-丁烯嵌段.产物DSC谱图表现出复杂的结晶熔融行为,存在多种结晶形态,出现熔融肩峰及双峰,与通常制得的LLDPE的结晶熔融行为有很大差别;结晶度和密度较低,并具有弹性体性质.

Relation Between Structure and Characteristics of Elastomers Prepared by Ethylene and 1-Butene Gas Oligamerization and Copolymerization with Highly Active Catalyst

Two elastomers have been prepared by gas copolymerization of ethylene and 1 butene with new highly active catalyst TiCl 4, Ti(OBu)₄/MgCl 2, SiO₂, ZnCl₂/alcohol/AlR₃. Triad sequence and comonomer distributions, average sequence length, run numbers are determined using₁₃ C NMR. It was found that the new catalyst has the properties to catalyze ethylene and 1-butene oligamerization and copolymerization in situ . The distribution of comonomer 1-butene in copolymers is not homogeneous, and the content of EBB] + BBB] in triad sequence distribution of elastomer is higher than that of common LLDPE. The melting and crystallization behavior of products are investigated by the method of DSC. The products show complicated crystallization and melting behavior, and lower melting point, density and degree of crystallinity. These results can be attributed to the existence of more 1-butene blocks in the copolymers chain and their participation in crystallization. The crystallization in copolymers may be physical crosslinking points and the products display the properties of elastomer.