Living poly(n-hexyl isocyanate) (PHIC) was deactivated with methacryloyl chloride to produce methacryl-terminated poly(n-hexyl isocyanate) (PHIC-MA) rodlike macromonomers. Radical copolymerization of methyl methacrylate (MMA) with PHIC-MA was performed using 2,2(')-azobis(isobutyronitrile) as an initiator in benzene at 60 degreesC to prepare poly(methyl methacrylate)-graft-poly(n-hexyl isocyanate) (PMMA-graft-PHIC) graft copolymers. The monomer reactivity ratios of MMA (M-1) and PHIC-MA (M-2) were evaluated as r(1) = 11.5 and r(2) =similar to 0, exhibiting (r)emarkably lower reactivity of PHIC-MA macromonomer than that of common macromonomers. The resultant graft copolymers were characterized using gel permeation chromatography equipped with low-angle laser light- scattering to determine the molecular weights, and equipped with a refractive index detector and an ultraviolet light detector to estimate a PHIC weight fraction of PMMA-graft-PHIC at the ith elution volume of the GPC chromatogram. There are 2-3 PHIC grafts per PMMA molecule, and the PHIC rodlike chains might be difficult to introduce into the PMMA main chains having higher molecular weights. A specific dimension of PMMA-graft-PHIC in solution was discussed in detail. (C) 2003 Elsevier Ltd. All rights reserved.