Effect of Maleic Anhydride Treatment on Steam and Water Absorption of Wood Polymer Composites Prepared from Wheat Straw, Cane Bagasse, and Teak Wood Sawdust Using Novolac as Matrix Y. P. PATIL, B. GAJRE, D. DUSANE, S. CHAVAN, S. MISHRA University Department of Chemical Technology, North Maharashtra University, Jalgaon 425001, India R eceived 11June1999;accepted 25 N ovem ber 1999 ABSTRACT: W heat straw ,cane bagasse,and teak saw dust (agrow aste) w ere sieved up to a 425-  m m esh size and em ployed for sheetpreparation with and withoutm aleic anhydride (M A )treatm ent using N ovolac resin in a 50 :50 (w /w )ratio.The shore D hardness of M A treated and untreated w ood polym er com posites (W PC s) w as m ea- sured. The M A treated W P C s show ed 2–3 tim es m ore hardness than that of the untreated respective W P C s. M oisture absorption had a detrim ental effect on the m e- chanical properties of the W P C s. M A treatm ent restricted sw elling and w ater and steam absorption in the agrow aste. T eak saw dust show ed the best results in all respects am ong the three W P C s. © 2000 John W iley & Sons, Inc. J A ppl P olym Sci 77: 2963–2967,2000 K ey w ords: m aleic anhydride;w ood polym er com posite;N ovolac resin INTRODUCTION W ood polym er com posites (W P C s) have attracted research in plastics and w ood technology.In som e low grade w ood species ithas been reported that the m echanical properties of W P C s are better than the pure w ood ofcorresponding species. 1 The capability of these m aterials as replacem ents for the consum ption ofw ood up to a certain lim it has enchanted the environm entalists as w ell. 2 The m ain obstacle that lim its the applications of W PCs is the com patibility between plastics and natural agrow aste m aterial. 3 T here are different reasons for the incom patibility betw een plastics and fiber-based filler. A ccordingly, various types ofrem edies have been suggested to overcom e this problem . 4–8 E L -B arbary 9 suggested peroxide bleaching ofrice straw and bagasse.D ong et al. 10 suggested a corona treatm ent to im prove tensile properties. It is also reported 11,12 thatalkali treatm ent im proves m echanical properties. W a- ter absorption affects the m echanical properties of W PCs. 13 W ood can be therm oplasticized for extrusion and m olding purposes.T herm oplastici- zation m ay be achieved by esterification,etherifi- cation, and grafting reactions. 4 E sterification serves to increase the com patibility by replacing the ™ OH groups, w hich are prone to m oisture absorption,in the cellulose. 14,15 EXPERIMENTAL W heat straw , cane bagasse, and saw dust w ere ground and sieved up to a m esh size of 425  m. T he w eightratio ofthe agrow aste to resin (50 :50, w /w )w as taken for the preparation ofW PC s. Novolac resin was prepared in the laboratory by reacting phenolwith form aldehyde in a m ole Correspondenceto: S.M ishra. Journal of A pplied P olym er Science,V ol.77,2963–2967 (2000) © 2000 John W iley & Sons,Inc. 2963