Composite samples were prepared from Poly(vinyl chloride)/low-density polyethylene (PVC/LDPE) blend, compatibilized by PA20 (methyl methacrylate-co-butyl acrylate copolymer), and reinforced by different levels of rubber-wood sawdust. To improve the mechanical properties of the composites, Silane A-137 (Octyltriethoxy silane), Silane A-1100 (gamma-aminopropyltriethoxy silane), or MAPE (maleic anhydride-grafted-polyethylene) were introduced. It was found that the additions of Silane A-137, Silane A-1100, and MAPE could improve tensile and impact properties of the composites, regardless of the sawdust contents. Physical or chemical interactions for all coupling agents with the wood-PVC/LDPE composites used were proposed in this work. Silane A-137 or MAPE tended to give better improvement in the mechanical properties of the composites than Silane A-1100, because of the presence of the nonpolar chain ends of Silane A-137 or MAPE molecules. Besides, the addition of either Silane A-137 and MAPE or Silane A-1100 and MAPE at different ratios into the wood-PVC/LDPE composites was also studied. The experimental results suggested that the optimum mechanical properties could be obtained using Silane A-137 : MAPE of 1% : 2% wt sawdust. The morphological and thermal properties of the composites were also examined using SEM and DMA techniques, respectively. (c) 2008 Wiley Periodicals, Inc.