The copolymerization of glyceryl methacrylate (GMA) and methyl methacrylate (MMA) was performed in a suspension polymerization system using ethylene glycol dimethacrylate (EGDMA) as crosslinker

resulting in the crosslinked microspheres GMA/MMA. Via ring-opening reaction

polyethylene glycol (PEG) was grafted onto the surfaces of microspheres GMA/MMA in the coupling graft manner

the immobilization of PEG was realized

and a kind of phase-transfer catalysts PEG-GMA/MMA

namely

triphase catalyst

was prepared.The effects of various factors on the grafting reaction of PEG were studied

and the reaction mechanism was investigated.The experimental results show that the immobilization of PEG on microspheres GMA/MMA can be conducted favorably

and this is a shortcut route to prepare triphase catalysts of PEG.It is found that Lewis catalysts are more effective than protonic acids for the ring-opening reaction of epoxy groups.The polarity of the solvents affects the coupling graft reaction between PEG and microspheres GMA/MMA greatly

and to use the solvents with higher polarity is advantageous to the graft reaction.In the graft reaction system

the additional crosslinking will be produced between the micromolecules on microspheres GMA/MMA if the used amount of the catalyst is excessive

and the additional crosslinking is adverse to the coupling graft of PEG.Under the suitable conditions

the PEG graft degree of the grafted microspheres PEG-GMA/MMA can get up to 0.20 g/g.