Abstract:

A well-defined silane-functionalized comonomer, 7-octenylethoxydimethylsilane (OEMS), was synthesized through hydrosilylation reaction of dimethylethoxysilane with 1,7-octadiene. Catalyzed by a vanadium complex bearing iminopyrrolide ligands (VCIP), the functional ethoxysilane-containing polyethylenes (PE-co-OEMS) were synthesized by copolymerization of ethylene with OEMS. The structure and properties of PE-co-OEMSs were characterized with ¹H NMR, ¹³C NMR, HT-GPC and DSC. It was found that catalytic activity still remained 1.2 kg·mmol^-1·h^-1 when OEMS feeding reached to 60 mmol·L^-1, and the OEMS incorporating in the copolymer was 1.3%(mol). Besides, the OEMS feeding had a great influence on the average molecular weight (M_w) and distribution (PDI) of copolymers. The Mw and PDI of PE-co-OEMS were 16900 and 2.1 when OEMS feeding was 30 mmol·L^-1. With further increasing the OEMS feeding, M_w increased and PDI became wider. The melting temperature (T_m) and crystallization enthalpy (ΔH_c) decreased with the increase of OEMS incorporation. The ethoxysilane-containing copolymers were easily crosslinked under the catalysis of trifluoromethanesulfonic acid, and the copolymer gel contents after crosslinking were nearly 100%.

Key words: polyethylene, silicone, crosslinking, polymer, preparation, synthesis

摘要：

通过二甲基乙氧基硅烷与1，7-辛二烯的硅氢加成反应，制备出一种含功能性基团的极性单体——7-辛烯基乙氧基二甲基硅烷（OEMS），在吡咯亚胺钒络合物（VCIP）的催化作用下，该单体可与乙烯配位共聚制备含功能性乙氧基硅烷的乙烯共聚物（PE-co-OEMS）。通过高温核磁共振氢谱及碳谱（¹H NMR和¹³C NMR）、高温凝胶渗透色谱（HT-GPC）和热分析（DSC）等测试方法对共聚物的结构和热性能进行了表征。结果显示，当共单体OEMS的投料量增大至60 mmol·L^-1时，共聚反应活性仍可保持在1.2 kg·mmol^-1·h^-1，OEMS单体插入率为1.3%（摩尔分数）；此外，OEMS投料量对于共聚物的分子量（M_w）和分子量分布（PDI）均具有较大的影响，当OEMS投料量为30 mmol·L^-1时，共聚物M_w为16900，PDI为2.1；若继续增大共单体的投料量，共聚物分子量增大且分子量分布变宽。熔点（T_m）和结晶焓（ΔH_c）随着OEMS插入率的增大而降低。在三氟甲磺酸作用下，PE-co-OEMS交联后凝胶含量接近100%。

关键词: 聚乙烯, 有机硅, 交联, 聚合物, 制备, 合成