Emulsion And Miniemulsion Polymerization Of MMA Via Reversible Addition-Fragmentation Transfer (RAFT) In The Presence Of Solubilizer

The reversible addition-fragmentation chain transfer (RAFT) miniemulsion polymerization of methyl methacrylate (MMA) in the presence of cyclodextrin (CD) has been investigated. cyclodextrin (CD) was found to act both as an efficient solubilizer for the RAFT agent (2-cyanopro-2-yl dithiobenzoate) and as a good stabilizer for the heterogeneous polymerization, such as conventional emulsion polymerization. The RAFT miniemulsion polymerizations with or without CD were compared in terms of kinetics and the molecular weight distribution. The problem of poor latex stability has been successfully resolved. No red floater was observed in miniemulsion system.A good result of the control over RAFT miniemulsion polymerization of MMA was obtained with CD. The increase of the molecular weight of poly(methyl methacrylate) showed a linear relationship with the monomer conversion. The polydispersity index of PMMA with CD (PDI=1.1~1.3) was smaller than that without CD. TEM photographs showed that PMMA latex particles produced with CD had smooth surfaces and uniform particle size.In addition, the effects of variable conditions on the miniemulsion RAFT polymerization of MMA monomer have been discussed, including emulsifier, co-stabilizer, RAFT agent and reaction temperature. Higher amount of sodium dodecyl sulfate and hexadecane was found in favor of improving the controllability of the system. Oil soluble initiator is beneficial to the controllability of the polymerization.The styrene (St) and MMA reversible addition-fragmentation chain transfer (RAFT) emulsion polymerization in the presence of cyclodextrin (CD) was also investigated. Almost no stable latex was obtained in our experimental conditions.