Synthesis and characterization of poly(methyl methacrylate)‐grafted silica microparticles

Abstract

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 1 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 13 C and 29 Si CP/MAS NMR. Their ability to initiate MMA photopolymerization was studied. The kinetics of MMA photopolymerization was followed by HPLC and 1 H-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 1 S used. Poly(methyl methacrylate)-grafted silica microparticles bearing high length grafts (DP n about 100) were synthesized.

Modification of Thermoplastics with Reactive Silanes and Siloxanes

“…PMMA-grafted silica microparticles were synthesized via radical photopolymerization of MMA, initiated from N,N-diethyldithiocarbamate (DEDT) groups previously bound to the silica surface ("grafting from") (Derouet & Thuc, 2008). The same technique of grafting was used for preparation of poly(octadecyl acrylate)(PODA)-grafted silicas (Mallik et al, 2009).…”

A New Stationary Phase with Improved Ligand Morphology Prepared by Polymerization of Styrene upon Initiator-attached Lichorsorb Silica Particles

“…The resultant organic-inorganic combined polymer can be used as stationary phases in chromatography. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Various silica materials including porous silica particles, 1,4,[6][7][11][12][13][14][15][16] silica beads, 2,5,10 silica monolith, 9 and silica capillary 3,8 have been used for such purposes. Atom transfer radical polymerization (ATRP) was used in the majority [1][2][3][4][5][6][7][8][9][10]16 of those studies while reversible addition-fragmentation chain transfer (RAFT) polymerization was used much less frequently.…”

A New Stationary Phase Prepared by Polymerization of Styrene on Initiator Bonded Porous Silica

“…Such organic-inorganic hybrid materials can serve as useful stationary phases in separation sciences. [1][2][3][4][5][6][7][8][9][10][11][12][13] Various silica materials were used including porous silica particles, 1,4,[6][7][11][12][13] silica beads, 2,5,10 silica monolith, 9 and silica capillary. 3,8 In the majority [1][2][3][4][5][6][7][8][9][10] of those studies, atom transfer radical polymerization (ATRP) was used to form an organic polymer layer on the silica surface.…”

“…On the other hand, reversible addition-fragmentation chain transfer (RAFT) polymerization was used only in a few cases. [11][12] Attachment of a diazo type initiator to silica surface was also reported. 13 In a particular study, an initiator was bonded to porous spherical organic monolith particles, and ATRP was used to add a polymer layer with ion exchange capability.…”

“…[17][18] No additional catalyst is required for polymerization. However, no good separation efficiency was obtained with the resultant stationary phases so far [11][12] in comparison with commercial C18 phases.…”