Copolymerization and thermal behavior of methyl methacrylate with N ‐(phenyl/ p ‐tolyl) itaconimides

This study describes the synthesis, characterization, and thermal behavior of copolymers of methyl methacrylate (MMA) and N ‐ p ‐tolyl itaconimide (PTI)/ N ‐phenyl itaconimide (I). Homopolymerization and copolymerization of N ‐(phenyl/ p ‐tolyl) itaconimide with MMA was carried out by use of various mole fractions of N ‐aryl itaconimide in the initial feed from 0.1 to 0.5, using azobisisobutyronitrile as an initiator and tetrahydrofuran as the solvent. The copolymer composition was determined by 1 H‐NMR spectroscopy using the proton resonance signals attributed to –OCH 3 of MMA (δ = 3.5–3.8 ppm) and the aromatic protons (δ = 7.0–7.5 ppm) of N ‐aryl itaconimide. The reactivity ratios of the monomers were found to be r 1 (PTI) = 1.33 ± 0.05/ r 2 (MMA) = 0.24 ± 0.03 and r 1 (I) = 1.465 ± 0.035/ r 2 (MMA) = 0.385 ± 0.005. The molecular weight of the copolymers decreased with increasing mole fraction of N ‐aryl itaconimide in the copolymers. Glass‐transition temperature ( T g ) and thermal stability of PMMA increased with increasing amounts of itaconimides in the polymer backbone. A significant increase in the percentage char yield at 700°C was observed on incorporation of a low mole fraction of N ‐aryl itaconimides. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1195–1202, 2003