화학공학소재연구정보센터
Journal of Applied Polymer Science, Vol.109, No.4, 2113-2127, 2008
Synthesis and characterization of poly(methyl methacrylate)-grafted silica microparticles
A procedure to synthesize poly(methyl methacrylate)-grafted silica microparticles was developed by using radical photopolymerization of methyl methacrylate (MMA) initiated from N,N-diethyldithiocarbamate (DEDT) groups previously bound to the silica surface (grafting "from"). The functionalization of silica microparticles with DEDT groups was performed in two steps: introduction of chlorinated functions onto the surface of silica particles, and then nucleophilic substitution of chlorines by DEDT functions via a S(N)2 mechanism. The study was performed with a Kieselgel (R) S silica which was initially chlorinated in surface, either by direct chlorination of silanols with thionyl chloride, or by using a condensation reaction between silanols and a chlorofunctional trialkoxysilane reagent, 4-(chloromethyl)phenyltrimethoxysilane and chloromethyltriethoxysilane, respectively. Three types of DEDT-functionalized silica microparticles were prepared with a good control of the reactions, and then characterized by solid-state C-13 and Si-29 CP/MAS NMR. Their ability to initiate MMA photopolymerization was studied. The kinetics of MMA photopolymerization was followed by HPLC and H-1-NMR. Whatever the silica used the grafting progresses very slowly. On the other hand, the conversion of MMA in PMMA grafts is depending on the structure of the DEDT-functionalized Kieselgel (R) S used. Poly(methyl methacrylate)-grafted silica microparticles bearing high length grafts (DPn about 100) were synthesized. (c) 2008 Wiley Periodicals, Inc.