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(Mw)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Mw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(Tm)和结晶焓(ΔHc)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%。
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, 13 C 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(Mw) 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, Mw increased and PDI became wider. The melting temperature(Tm) and crystallization enthalpy(ΔHc) 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%.