Preparation of flat porous carbon films from paper-thin wood shavings and control of their mechanical, electrical and magnetic properties

A method for preparing flat porous carbonized films (FPCFs) by carbonizing paper-thin wood shavings was developed, and their structures and properties were investigated. The FPCFs were binder-free and had horizontal honeycomb structures consisting of macropores of 2-50 μm arising from tracheids and pittings. The FPCFs with approximate dimensions of 120 mm × 104 mm × 113 μm showed some flexibility. They were effectively reinforced and became twistable by introducing styrene-butadiene rubber (SBR) into the macropores via impregnation. The SBR-modified FPCFs carbonized at 1023 K retained electrical conductivity on the order of 10^-3 S/m with the inclusion of SBR concentrations up to 15 mg/cm². The electrical conductivity of FPCFs carbonized at 773 K changed from nonconductive to 10^{- 2} S/m by impregnating the macropores with electrically conductive carbon paste or to 10⁵ S/m with Cu chemical plating. The FPCFs became responsive to a magnetic field by impregnating the macropores with a magnetic fluid or by creating ferrites through chemical reactions within the macropores.