Monomer Structure and Solvent Effects on Copolymer Composition in (Meth)acrylate Radical Copolymerization

• Published in: Industrial & engineering chemistry research 2018-04, Vol.57 (15), p.5215-5227
• Main Authors: Rooney, Thomas R, Hutchinson, Robin A
• Format: Article
• Language: English
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/acs.iecr.8b00451

Solvent effects on reactivity ratios (ri ) and overall composition-averaged copolymer propagation rate coefficients (k p,cop) are generally not observed during methacrylic ester radical copolymerization. However, hydroxyl-bearing comonomers, such as 2-hydroxyethyl methacrylate (HEMA), lead to significant deviations from expectation for both ri and k p,cop, an effect that is highly dependent on solvent choice and rooted in hydrogen bond interactions. The current understanding of the influence of hydrogen bonding on organic solution (meth)­acrylic ester radical (co)­polymerization kinetics is reviewed by summarizing trends in structure/reactivity for methacrylate homopropagation rate coefficients (k p) and methacrylate macromonomer relative reactivity during copolymerization. In addition, the peculiarities that characterize the apparent enhanced reactivity of hydroxyl-bearing monomers during copolymerization are outlined. Finally, a modeling framework to systematically capture the effects of solvent and hydrogen bonding on copolymer composition, through specific intramolecular hydrogen bond associations between monomer and growing chain, is presented for several methacrylate, acrylate, and styrene copolymerizations.