Synthesis of Micrometer‐Size Poly(Methyl Methacrylate) Particles by Utilizing Microsuspension Iodine Transfer Polymerization (ms ITP): Kinetic Approach

• Published in: Macromolecular Theory and Simulations Vol. 27; no. 5
• Main Authors: Okubo, Masayoshi, Kitayama, Yukiya, Yamashita, Nobuko, Liu, Xiang, Huang, Chujuan
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley 01.09.2018; Wiley Subscription Services, Inc
• Subjects: Emulsion polymerization; Iodine; iodine transfer polymerization; microsuspension polymerization; ms ITP; Peroxide; Polymerization; Polymethylmethacrylate; radical exit depression (RED) effect
• ISSN: 1022-1344; 1521-3919
• DOI: 10.1002/mats.201800029

In a previous work, microsuspension ITP (ms ITP) of methyl methacrylate (MMA) using iodoform (CHI3) as a chain transfer agent and benzoyl peroxide (BPO) as an initiator could be successfully carried out at 80 °C for the synthesis of micrometer‐size poly(MMA) (PMMA) particles without the byproduct of submicrometer‐size particles. Whereas, in microsuspension conventional radical polymerization (ms CRP) at the same conditions except for non‐use of CHI3, about half amount of PMMA was formed as submicrometer‐size byproduct particles by accompanying emulsion polymerization. In this article, kinetic simulations of ITP and CRP in bulk systems, which, respectively, correspond to those within MMA droplets in ms ITP and ms CRP, are performed using PREDICI software from CiTGmbH to understand the successful reason of the ms ITP of MMA. The simulation results of the ITP indicate that the concentrations of MMA oligomer radicals having BPO initiator fragment and vinyl group as end‐group, which seem to exit from MMA droplets and accompany emulsion polymerization in the aqueous medium in the ms CRP, remarkably decreased in the presence of CHI3. This strongly supports the idea “RED effect” proposed in the previous article to explain the success of the ms ITP of MMA. Kinetic simulation on concentrations of methyl methacrylate (MMA) oligomer radicals having different end‐groups is carried out to understand successful ms ITP of MMA, which is one of “hydrophilic” monomers, using iodoform (CHI3) as a chain transfer agent and benzoyl peroxide as an initiator for the synthesis of micrometer‐size poly(MMA) particles without submicrometer‐size byproduct particles.