In this study, free-radical copolymerizations of N-phthalimidomethyl Methacrylate (NPMMA) with 2-Hydroxyethyl Methacrylate (HEMA) were carried out at 70 °C in dimethylformamide (DMF) solution in the presence of 2, 2' Azobisisobutyronitrile at low conversions. The copolymers were characterized by Fourier transform infrared (FTIR), 1H-NMR, and 13C-NMR techniques. The molecular weight and molecular distribution values of the copolymers were determined with gel permeation chromatography (GPC). The composition of the copolymers was established by 1H-NMR analysis. The monomer reactivity ratios r1 (NPMMA) and r2 (HEMA) were determined with the linearized copolymerization equations of the Kelen–Tüdös and Fineman–Ross methods to be r1 = 0.59, r2 = 1.93 and r1 = 0.58, r2 = 1.97, respectively. The effect of the comonomer units on the thermal stability of the copolymers was studied by thermogravimetric analysis (TGA). The initial decomposition temperatures of the resultant copolymers decreased with increasing mole fraction of HEMA, which indicate that heat resistance of copolymer improved by increasing NPMMA units. Thermogravimetric analysis/ differential thermal analysis (TGA/DTA) system was also applied to investigate the glass transition temperatures, Tg. The change of Tg as a function of the copolymer composition was investigated and the results were applied to Gordon-Taylor and Johnston equations.
Copolymerization; monomer reactivity ratios; glass-transition temperature; 2-Hydroxyethyl Methacrylate; N-phthalimidomethyl Methacrylate.