Kinetics of Iodine Transfer Miniemulsion Polymerization of Butyl Acrylate
Iodine transfer polymerization(ITP)is one kind of reversible-deactivation radical polymerization method using facile chain mediators,and the miniemulsion ITP process can produce high stable polymer emulsions with high chain mediation efficiencies.Butyl acrylate(BA)iodine transfer miniemulsion polymerizations were carried out using 2,2'-azobis(2-methylpropionamidine)dihydrochloride(AIBA)as a initiator and iodoform as a transfer agent,and effects of AIBA concentration,iodoform concentration and temperature on kinetics of BA polymerization were investigated.The reaction of BA iodine transfer miniemulsion polymerization was fast and corresponded to the characteristics of the first-order reaction in early period.Its apparent reaction rates were increased with the increase of AIBA concentration and temperature,and it varied slightly as the iodoform concentration changed.The molecular weights of PBA could be adjusted by the iodoform concentration and polymerization conversion.As the iodoform molar concentration to monomer decreased from 1‰ to 0.25‰,the number average molecular weight of PBA was increased from 1.2×105 to 5.0×105 when BA conversion was greater than 90％.PMMA-b-PBA-b-PMMA latex with particles of larger average size and molecular weight was prepared(where the mole ratio of BA and MMA was 1:1)by a chain extension of PBA by methyl methacrylate(MMA)using PBA as a macromolecular mediator and seeded latex particles.Both BA and MMA polymerizations exhibited living nature as evidenced by the kinetics behavior and structure of obtained polymers.
butyl acrylateiodine transfer polymerizationminiemulsion polymerizationpolymerization reaction ratemolecular weight
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