the hybrid behavior of surface-treated mica and hardwood chemithermomechanical pulp (ctmp) in pvc composites was investigated. in order to improve the compatibility of wood fibers with pvc and surface-coated mica, ctmp was subjected to different surface modifications by pretreating the fibers with maleic anhydride (ma), a mixture of ma and na-silicate, and with an isocyanate (pmppic). the effect exerted by the concentration of reinforcements, composition of hybrid reinforcements as well as the treatment of ctmp, on the mechanical properties of the hybrid composites were evaluated. in general, these properties improved compared to those of uncoated ctmp/mica-filled composites. moreover, pmppic treatment ranked best followed by ma-and ma+silicate treatments. the optimal concentration of reinforcements and their compositions, which provided superior properties, varied according to the nature of the treatment of ctmp and of the individual mechanical properties themselves