the present invention relates to cellulosic material / polymer composites and foams containing zeolite , blowing agent and masterbatch for making such composites and foams , and processes therefor . more specifically , in the embodiments of the present invention directed to cellulosic material / polymer foams , the compositions comprise one or more zeolites and one or more foaming agents , wherein the foaming agent preferably is carried by the zeolite and evolves to form foamed products when processed with foamable materials . the present invention also comprises blowing agent composition comprised of zeolite and foaming agent combination , and masterbatch composition comprised of zeolite , foaming agent and cellulosic material . the zeolite provides several benefits to such compositions and foams . the zeolites also have been found to reduce the tendency of the wood portion of the compositions and foams to discolor and have biocidal activity which reduces the tendency of the compostions and foams to degrade from bacterial and fungal attack .