Facile synthesis of graft copolymers containing rigid poly(dialkyl fumarate) branches by macromonomer method

ABSTRACT Graft copolymers show microphase separated structure as seen in block copolymers and have lower intrinsic viscosity than block copolymers because of a branching structure. Therefore, considering molding processability, especially for polymers containing rigid segments, graft copolymers are useful architectures. In this work, graft copolymers containing rigid poly(diisopropyl fumarate) (PDiPF) branches were synthesized by full free‐radical polymerization process. First, synthesis of PDiPF macromonomers by addition‐fragmentation chain transfer (AFCT) was investigated. 2,2‐Dimethyl‐4‐methylene‐pentanedioic acid dimethyl ester was found to be an efficient AFCT agent for diisopropyl fumarate (DiPF) polymerization because of the suppression of undesired primary radical termination, which significantly took place when common AFCT agent, methyl 2‐(bromomethyl)acrylate, was used. Copolymerization of PDiPF macromonomer with ethyl acrylate accomplished the generation of the graft copolymer having flexible poly(ethyl acrylate) backbone and rigid PDiPF branches. The graft copolymer showed a microphase separated structure, high transparency, and characteristic thermal properties to PDiPF and poly(ethyl acrylate). © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2474–2480 Graft copolymers consisting of rigid poly(diisopropyl fumarate) branches and a soft poly(ethyl acrylate) backbone were synthesized by full free‐radical polymerization process. 2,2‐Dimethyl‐4‐methylene‐pentanedioic acid dimethyl ester was found to be an efficient addition‐fragmentation chain transfer agent for diisopropyl fumarate polymerization to generate a poly(diisopropyl fumarate) macromonomer. Copolymerization of the poly(diisopropyl fumarate) macromonomer with ethyl acrylate accomplished the generation of the graft copolymer having a flexible backbone and rigid branches, and which is transparent and shows a microphase separated structure.