The present invention discloses a method for producing a reinforced organic polymeric materal by mixing a dispersion comprising a plasticizer and cellulosic nanowhiskers into a carbon matrix. The nanowhiskers are dispersed in a liquid dispersion and pumped into extruder in which as arranged the least partially molten carbon matrix. The extrusion process will thotoughly mix the celluloe whiskers into the carbon matrix, thus providing a homogenous mixture being highly reinforced. The present invention further discloses a polymer produced according to the above process comprising a CAB7CNW mixture , as well as aprocess for producing said whiskers.