Synthesis and chemical modification of maleic anhydride copolymers with phthalimide groups

Background: Maleic anhydride (MAN) copolymers with methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, and butyl acrylate monomers at 1:1 mole ratios were synthesized by free radical polymerization in the presence of α,α0-azobis(isobutyronitrile) as initiator and dry ethyl acetate as solvent. Results: Copolymer compositions were obtained using related proton nuclear magnetic resonance (1HNMR) spectra, and the polydispersity of the copolymers was determined by gel permeation chromatography. Then, a solution of phthalimide salt as a nucleophilic reagent reacted through the ring opening of anhydride groups in copolymers resulting to modified copolymers IPht to VPht. All the prepared polymers were characterized by Fourier transform infrared and 1H NMR spectroscopic techniques. The glass transition temperature (Tg) of all copolymers before and after modification was determined by dynamic mechanical thermal analysis (DMTA). Conclusions: It was shown that chemical modification of MAN copolymers with phthalimide substituents as side chains decreased the free volume of the polymers, and therefore, the rigidity and Tg are increased. Solubility of the copolymer products was tested in some organic solvents.