异相后过渡金属聚乙烯的结构与性能

Structure and Properties of Branched Polyethylene Prepared by Heterogeneous(α-Diimine) Nickel Catalyst

采用负载α-二亚胺镍配合物催化乙烯聚合制备不同支化度的聚乙烯(PE),应用核磁共振分析仪、差示扫描量热仪和广角X-射线衍射仪分析了异相后过渡金属催化剂制备的支化聚乙烯的支化结构与熔融行为、结晶行为及晶型特征。探讨支化度对PE熔融行为、结晶行为和晶型等的影响。随着支链度的提高,熔融温度和结晶温度都降低,熔融峰形变宽。当支链度为100.90时,降温曲线出现两个峰,衍射角在23°(2θ)附近,(200)晶面衍射峰消失,表明聚乙烯的型态为弹性态。

Polyethylene （PE） products with different degree of branching were prepared through ethylene polymerization catalyzed with heterogeneous α-diimine nickel complexes, and the effects of branching degree on melting behavior, crystal form of PE were investigated. The branching degrees were measured by 13C-NMR, melting points and crystal points of the products were measured by DSC. As the branching degree increases, the melting points and crystallization temperature of the products decrease, the melting points and crystallization temperature of the products decreases, the melting range becomes widened. Double peaks appear on DSC cooling curves as the branching degree reaches 100.90, and the diffraction peak of crystal surface （200） approximacly at 23° （2θ） disappears, which indicates that PE becomes amorphous.