The present disclosure describes a method for preparing a paper nanocomposite, including: continuously providing a first suspension that includes lignocellulosic pulp fibers, cellulose nanofibrils, carbon nanotubes, and a cationic surfactant; continuously adding a second suspension to the first suspension to provide a slurry, the second suspension includes lignocellulosic pulp fibers, cellulose nanofibrils, carbon nanotubes, and an anionic surfactant; depositing the slurry comprising the first and second suspensions onto the substrate; and dewatering the slurry to form the paper nanocomposite.

Cellulose nanofibers (CNF) act as a dispersing agent to directly exfoliate graphite in an aqueous solution using sonication. The resulting suspension has graphite flakes, each having 2-20 monolayers, a relatively large lateral dimension, and a plurality of CNF decorating its surfaces and edges. The dispersing effect of the CNF allows the graphite-CNF suspension to be stored without degradation until desired use. The graphite-CNF suspension can be used to form various composite structures, such as by spraying, coating, pouring, extruding, or printing the suspension, and then drying the suspension. The resulting composite structures have improved tensile strength and toughness due to hydrogen bond interactions between the CNF and graphite.

Cellulose nanofibers (CNF) act as a dispersing agent to directly exfoliate graphite in an aqueous solution using sonication. The resulting suspension has graphite flakes, each having 2-20 monolayers, a relatively large lateral dimension, and a plurality of CNF decorating its surfaces and edges. The dispersing effect of the CNF allows the graphite-CNF suspension to be stored without degradation until desired use. The graphite-CNF suspension can be used to form various composite structures, such as by spraying, coating, pouring, extruding, or printing the suspension, and then drying the suspension. The resulting composite structures have improved tensile strength and toughness due to hydrogen bond interactions between the CNF and graphite.

A method for producing a roll-type gas diffusion layer is disclosed. The method includes preparing a carbon paper from carbon fiber chops having a low modulus of 10 to 100 Gpa; impregnating the prepared carbon paper with a phenol resin, and then carbonizing the resin-impregnated carbon paper at 1,800 to 2,400 C.; forming a microporous polytetrafluoroethylene resin layer on one side of the carbonized carbon paper, to prepare a gas diffusion layer sheet; and winding the prepared gas diffusion layer sheet on a roll. Since the roll of gas diffusion layer is formed using the carbon fiber chops having a low modulus, the gas diffusion layer exhibits excellent and uniform spreading properties. Therefore, sealing between the gas diffusion layer and the fuel cell separation plate is reliably secured without using a separate binder.

A method for producing a roll-type gas diffusion layer is disclosed. The method includes preparing a carbon paper from carbon fiber chops having a low modulus of 10 to 100 Gpa; impregnating the prepared carbon paper with a phenol resin, and then carbonizing the resin-impregnated carbon paper at 1,800 to 2,400 C.; forming a microporous polytetrafluoroethylene resin layer on one side of the carbonized carbon paper, to prepare a gas diffusion layer sheet; and winding the prepared gas diffusion layer sheet on a roll. Since the roll of gas diffusion layer is formed using the carbon fiber chops having a low modulus, the gas diffusion layer exhibits excellent and uniform spreading properties. Therefore, sealing between the gas diffusion layer and the fuel cell separation plate is reliably secured without using a separate binder.

Methods and systems of the present invention use cellulose-containing materials, which may include post-consumer waste garments, scrap fabric and/or various biomass materials as a raw feed material to produce isolated cellulose molecules that can be used in the textile and apparel industries, and in other industries. A multi-stage process is provided, in which cellulose-containing feed material is subjected to one or more pretreatment stages, followed by a dissolution treatment and isolation of cellulose molecules. Isolated cellulose molecules may be used in a variety of downstream applications. Methods and systems for carbonizing precursor fibers to produce carbonized fibers having desired properties and three-dimensional configurations are provided.

The present application discloses a flexible rollable carbon paper, and the carbon paper has a thickness of 0.150.25 mm, a volume density of 0.200.45 g/cm.sup.3, and a porosity of 7090%; a flexible strength of 2060 Mpa, and a bending degree of 60180; a surface resistivity 100 m-cm; and a thermal conductivity 0.8 W/(m.Math.K). The present application also discloses the processing technology and related processing systems of the paper and its intermediates.

The present application discloses a flexible rollable carbon paper, and the carbon paper has a thickness of 0.150.25 mm, a volume density of 0.200.45 g/cm.sup.3, and a porosity of 7090%; a flexible strength of 2060 Mpa, and a bending degree of 60180; a surface resistivity 100 m-cm; and a thermal conductivity 0.8 W/(m.Math.K). The present application also discloses the processing technology and related processing systems of the paper and its intermediates.

The present invention provides an electromagnetic wave absorbing sheet which contains: conductive short fibers; and soft magnetic particles, each of which is covered by an insulating material.

The present invention provides an electromagnetic wave absorbing sheet which contains: conductive short fibers; and soft magnetic particles, each of which is covered by an insulating material.