摘要
使用Et(Ind)2ZrCl2/MAO催化剂催化乙烯和3种ω-对甲苯基-α-烯烃(对甲苯基-1-丙烯,4-对甲苯基-1-丁烯,6-对甲苯基-1-己烯)共聚,主要研究了共单体加入量对催化剂活性和所得共聚物性能的影响.4-对甲苯基-1-丁烯表现出最好的共聚性能.使用1H-NMR、13C-NMR、GPC和DSC对共聚物进行了表征.
Modification of polyethylene with polar groups and/or polar polymer side chains has been an issue forboth academic and industry fields for a long time. Many method have been presented to prepare functional polyethylene, among which the post-functional method has find its industry applications. However, this method shows many disadvantages in controlling polymer structure. The reactive monomer method is characterized by good control of polymer chain structure. We have prepared an ethylene/p-allyholuene copolymer by Et （Ind）2ZrCl2/MAO. Thiscopolymer can be transferred to polyethylene graft copolymers using graft-from technique from the site of benzyl groups. In this paper,copolymerization of ethylene with three kinds of ω-p-methylphenyl-α-olefins,p-methylphenyl-1-propylene （ AC3 ）, 4-p-methylphenyl-l-butene （ BC4 ） and 6-p-methylphenyl-1-hexene （ HC6 ） using Et （Ind）2 ZrCI2/MAO as a catalyst was performed in order to compare the copolymerization abilities of the three reactive comonomers. Three comonomers were synthesized by the coupling reactions between benzyl or aryl metal （magnesium or lithium） and alkenyl halide. The comonomers were purified to get the polymerization grade. Ethylene/reactivecomonomer copolymerization was carried out under 1.01 × 10^5 Pa of ethylene with variations of the comonomer quality in the feed. The copolymers were characterized with ^1H-NMR, ^13 C-NMR, GPC and DSC. With the feed of comonomers the catalyst activity increased, reached a maximum value and then decreased. Under the same concentration of comonomers,the highest catalyst activity occurred in the BC4 system. The content of comonomer in copolymers increased with the comonomer in the feed. Under the same concentration of comonomers,the content ofcomonomer in copolymers could be used to compare the copolymerization ability of the comonomers. The examination results showed that the best copolymerization ability came from BC4. With the increase of the content of comonomer in copolymers, the melting point of copolymers decreases, and the peak in DCS curves becomes broad. This is because the incorporation of comonomers destroyed the crystal of polyethylene. The incorporation of comonomers in copolymers caused a decrease in polymer molecular weight. The possible reason was that more β-H chain transfer reactions were induced by the comonomer. Three kinds of copolymers were characterized with ^1H-and ^13 C-NMR, all of the H and C atoms could be found in their NMR spectra. And no evidence proved that two comonomer molecules were connected directly. The above results showed that BC4 was a favorable comonomer which had the best incorporation ability.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2008年第4期371-377,共7页
Acta Polymerica Sinica
基金
国家自然科学重点基金(基金号20734002)
国家自然科学基金(基金号50703044)
SINOPEC(中国石油化工集团公司)资助项目
关键词
聚乙烯
对甲苯基烯烃
共聚合
茂金属
功能化
Polyethylene, p-Methylphenyl-α-olefin, Copolymerization, Metallocene, Functionalization
