Free radical copolymerization of N-(4-carboxyphenyl)maleimide with hydropropyl methacrylate

The free radical copolymerization of N-(4-carboxyphenyl)maleimide (CPMI) (M-1) with hydropropyl methacrylate (HPMA) (M-2) was carried out with 2,2'-azobis(isobutyronitrile) (AIBN) as an initiator in ethyl acetate at 75degreesC. The composition of copolymer prepared at low conversion was determined by elemental analysis. The monomer reactivity ratios were found to be r(1) = 0.31 and r(2) = 1.11 as determined by the YBR equation. The number-average molecular weight and polydispersity were determined by gel permeation chromatography (GPC). Furthermore, the solvent effect on this copolymerization system was also investigated. The resulting copolymer was characterized by FTIR and H-1-NMR spectroscopy. The thermal stability of copolymers was determined by thermogravimetric analysis (TGA). It was found that the copolymer shows step-by-step degradation, the initial decomposition temperature (T-i), and final decomposition temperature (T-f) increased with increasing the component of CPMI in copolymer.