Constituting a special redox surface-initiating system and realizing graft-polymerization of GMA on polysulfone microfiltration membrane

A special redox surface-initiating system, tertiary aromatic aniline/BPO (benzoyl peroxide, BPO), was constituted at the interface between polysulfone (PSF) microfiltration membrane and an organic solution, in which the monomer glycidyl methacrylate (GMA) and BPO were dissolved, and the graft-polymerization of GMA on the porous membrane of PSF was smoothly carried out by the initiating of the surface initiating system, getting the grafted membrane PSF-g-PGMA, which is a precursor of many functional composite membranes. The microfiltration membrane of chloromethylated polysulfone (CMPSF) was first prepared by the method of immersion-precipitation phase transformation; subsequently the CMPSF membrane was modified with 3-hydroxy-N,N-diethylaniline (HDEA) as reagent, and through the nucleophilic substitution reaction between the chloromethyl group on CMPSF membrane and the hydroxyl group of HDEA, tertiary aromatic aniline group DEA was bonded on the PSF microfiltration membrane, obtaining the modified membrane PSF-DEA; finally, the graft-polymerization of GMA was successfully realizing by the surface-initiating system of DEA/BPO, getting the grafted porous membrane PSF-g-PGMA. The grafted membrane was characterization by FTIR and SEM. The experimental results show that the reaction between the chloromethyl group on CMPSF membrane and HDEA in the solution belongs to unimolecular nucleophilic substitutions. For the graft-polymerization of GMA, the appropriate temperature is 70 °C, the suitable mass percent concentration of GMA in solution is 5%, and the optimal concentration of BPO is 1.5% of monomer GMA mass. For the grafted membrane PSF-g-PGMA prepared under the optimal reaction conditions, the grafting degree of PGMA can reach 0.86 g/cm².