Ultra-high molecular weight polyethylene with hybrid porous structure

A novel method of a hybrid porous structure preparation in UHMWPE was developed. A porous structure consisted of large 50-900 mu m and medium-size 50 nm-4 mu m macropores together with mesopores. The polymodal structure was prepared via water leaching of UHMWPE-NaCl composite followed by o-xylene treatment at a temperature of 99-103 degrees C with further supercritical drying in CO2. Scanning electron micrograph showed the formation of additional porous structure on the large macropores' walls surface formed by lamellar crystals. The size and quantity of the lamellar crystals depended on the heating temperature and could be varied over a wide range. The formation of the hybrid porous structure in UHMWPE was accompanied by a significant increase in the crystallinity degree (up to 81%) and specific surface area (up to 65 m(2)/g). The mechanical behavior of the UHMWPE with hybrid porous structure was investigated by DMA. The change in the UHMWPE crystal structure led to a change in the UHMWPE relaxation behavior and to an increase of damping ability.