论文部分内容阅读
以乙二醇二甲基丙烯酸酯为交联剂,采用悬浮聚合方法,制备了甲基丙烯酸缩水甘油酯(GMA)和甲基丙烯酸甲酯(MMA)的交联微球GMA/MMA.使用Lewis酸催化剂,通过环氧键的开环反应,将聚乙二醇(PEG)偶合接枝在交联微球GMA/MMA表面,实现了PEG的固载化,制得了三相相转移催化剂PEG-GMA/MMA.重点考察了各种因素对PEG接枝固载过程的影响,并研究了反应机理.实验结果表明,以交联微球GMA/MMA为载体,可以顺利地实现PEG的固载化,这是制备PEG三相相转移催化剂的简捷途径.实验发现,Lewis酸也能催化环氧键的开环反应,而且比质子酸的催化更加有效.溶剂的极性对偶合接枝反应的影响较大,采用极性大的溶剂有利于PEG的接枝固载.偶合接枝体系中,过高的催化剂用量会导致PEG双端羟基参与接枝反应,使载体表面大分子之间发生附加交联,不利于PEG的接枝固载.在适宜的反应条件下,接枝微球PEG-GMA/MMA表面的PEG接枝度可达0.20 g/g.
Crosslinked microspheres GMA / MMA with glycidyl methacrylate (GMA) and methylmethacrylate (MMA) were prepared by suspension polymerization using ethylene glycol dimethacrylate as the crosslinking agent. Acid catalyst, the PEG was coupled and grafted on the surface of crosslinked microspheres GMA / MMA by the ring-opening reaction of epoxy bonds to immobilize the PEG. Three-phase phase-transfer catalyst PEG- GMA / MMA.The influence of various factors on the grafting and immobilization of PEG was investigated, and the reaction mechanism was studied.The experimental results show that the immobilization of PEG can be successfully achieved with the crosslinked microspheres GMA / MMA as carrier , Which is a simple and convenient way to prepare PEG three-phase phase transfer catalyst.It is found that Lewis acid can also catalyze the ring-opening reaction of epoxy bonds and is more effective than the proton acid catalysis. The polarity of the solvent affects the coupling grafting reaction Larger, the use of a large polar solvent is conducive to the PEG graft grafting.Coupled graft system, the high amount of catalyst will lead to PEG double hydroxyl groups involved in the grafting reaction, the carrier surface molecules occur between additional Is not conducive to the PEG graft-immobilization.Under the appropriate reaction conditions, the grafted microspheres PEG-GMA / MM A surface PEG grafting degree up to 0.20 g / g.