N-pentafluorophenyl maleimide (PFPMI) was synthesized. The homo and copolymers of PFPMI with methyl methacrylate (MMA) were prepared. The monomer reactivity ratio, r(1) (PFPMI) and r(2) (MMA) were 0.389 and 1.06 respectively. Q and e values for PFPMI were calculated as 1.00 and 1.30. The refractive indexes of poly(PFPMI) and PMMA were found to be similar: 1.4989 and 1.4953 at 532 nm, respectively. The copolymers exhibited no light scattering, and the film was very transparent. The glass transition temperatures of the PFPMI-co-MMA were in the range of 140 degrees C-180 degrees C with the PFPMI content from 18.8 to 65 mol% and the copolymers obtained have high thermal stability (similar to 370 degrees C). The water absorption of PFPMI-co-MMA was greatly reduced as compared with that of pure PMMA. (C) 2011 Published by Elsevier Ltd.