Filamentous alumina–chitosan porous structures produced by gelcasting

Porous filamentous macroelements with tunable properties were developed using alumina–chitosan fibers produced by gelcasting extrusion. The initial suspension was prepared as a dilute aqueous acetic acid solution containing 13 vol% of alumina particles and 1.3 vol% of dissolved chitosan. After extrusion, coagulation in an NaOH bath and drying, 300 μm diameter continuous fibers (9 vol% of chitosan) were compacted and sintered at different temperatures (1100–1500 °C) to produce 40×40 mm2 cylindrical macroelements. The effects of the thermal treatment temperature on the porosity, specific surface area, mechanical strength and microstructure of the macroelements were evaluated. It was verified that these properties can be controllably modified in a wide range, depending on the sintering conditions.