摘要
本文讨论了烯丙基类端基聚氧乙烯(PEO)大单体与苯乙烯进行自由基型以及阳离子型的共聚。采用BF_3·(OC_2H_5)_2催化体系进行PEO大单体与苯乙烯阳离子共聚时,所得共聚物具有较自由基引发体系为高的接枝数,但共聚产率仍相对较低。采用Al(C_2H_5)_3为催化剂或采用甲基烯丙基为端基的PEO大单体为中间体时,所得共聚物具有更大的接枝数和高的产率。
The possibility for cationic copolymerization of allyllike endgroup PEO macromer with styrene was examined. The results show that the copolymerwith relative higher number of branch (Nb=5) than one from free radical system,but in a lower yield,was obtained when BF3·OEt2 was used as initiator. The lower yield of copolymerization is explained in the terms of exchanging reaction existed between the chain unit in macromer and the ether part in intiator. Further tests show that one can get copolymer with higher number of branch when using methyl-allyl PEO macromer instead of allyl one. Moreover, several factors affecting the copolymerization were tested, and a method for purifying the copolymer by fractionation precipitation was set up.
