SYNOPSISWood plastic composites ( WPC) of simul were prepared by gamma radiation using butylacrylate (BA) and methylmethacrylate (MMA) as the monomer and methanol as the swelling agent at 9 : 1 ( v / v ) ratio. IR spectra of simul, bulk polymer of BA (or MMA) film, and WPC of different polymer loadings ranging from 18 to 115% were studied. Increase of the characteristic peak intensity at 1735 cm-' (C = 0 vibration for acetyl groups) over that of 1620 cm-' (conjugated aryl carbonyl groups) along with the increase of polymer loading of simul with the monomer indicates that the graft copolymerization took place between the monomer and the simul wood matrix. 0 1993 John Wiley & Sons, Inc. I NTRO D UCTl 0 NRecently many authors reported on the wood plastic composites formation using different monomers. Synergistic yields of polymer loading were also reported in the presence of additives.',2 Analysis of composites by X-ray diffraction and scanning electron microscope (SEM) revealed the graft copolymerization of the monomer methylmethacrylate (MMA) with the wood m a t r i~.~ IR spectroscopy is known to elucidate functional groups and linkages in any chemical structure analysis. Recently wood polymer composites of Geronggang, a tropical hard wood of Malaysia were analysed by FTIR spectroscopy.4 It was observed that graft copolymerization occurred with the wood components and acrylonitrile and styrene, but not with MMA. The purpose of the present work is to study the IR spectra of the simul, a soft wood of Bangladesh, and its composites with n -butylacrylate (BA) and MMA in order to determine, in further support of X-ray diffraction and SEM analysis, the extent of copolymerization of simul with BA and MMA.