Synthetic Procedures for Preparing Cross-Linkable Acrylic Comb-Like Copolymers Via Macromonomers

Abstract

A versatile procedure was developed for synthesis of acrylic comb-like copolymers in three steps: (1) Hydroxyl terminated oligomers were synthesized from methyl methacrylate, butyl acrylate and glycidyl acrylate by free-radical initiated addition polymerization using a functional chain transfer agent, 2-mercaptoethanol, and very low initiator levels. (2) The oligomers were converted to macromonomers by reaction with isocyanatoethyl methacrylate. (3) The macromonomers were polymerized by free-radical initiation. Conditions during the first stage must be carefully selected to minimize formation of difunctional material which could cause gelation in the third stage. A variety of structures can be made such as comb-like copolymers with homopolymer tines or comb-like homopolymers with copolymer tines. Functional groups can be introduced by copolymerizing glycidyl acrylate into the macromonomer. Assignment of comb-like structures is not rigorously proven but is strongly supported by the synthetic route and by DSC, FT-IR and chromatographic data.