Abstract: A gas diffusion substrate includes a non-woven network of carbon fibres, the carbon fibres are graphitised but the non-woven network has not been subjected to a graphitisation process. A mixture of graphitic particles and hydrophobic polymer is disposed within the network. The longest dimension of at least 90% of the graphitic particles is less than 100 ?m. A process for manufacturing gas diffusion substrates includes depositing a slurry of graphitised carbon fibres onto a porous bed forming a wet fibre network, preparing a suspension of graphitic particles and hydrophobic polymer, applying onto, and pulling the suspension into, the network, and drying and firing the network. Another process includes mixing a first slurry of graphitic particles and hydrophobic polymer with a second slurry of graphitised carbon fibres and liquid forming a third slurry, depositing the third slurry onto a porous bed forming a fibre-containing layer, and drying and firing the layer.

Abstract: A gas diffusion substrate includes a non-woven network of carbon fibres, the carbon fibres are graphitised but the non-woven network has not been subjected to a graphitisation process. A mixture of graphitic particles and hydrophobic polymer is disposed within the network. The longest dimension of at least 90% of the graphitic particles is less than 100 ?m. A process for manufacturing gas diffusion substrates includes depositing a slurry of graphitised carbon fibres onto a porous bed forming a wet fibre network, preparing a suspension of graphitic particles and hydrophobic polymer, applying onto, and pulling the suspension into, the network, and drying and firing the network. Another process includes mixing a first slurry of graphitic particles and hydrophobic polymer with a second slurry of graphitised carbon fibres and liquid forming a third slurry, depositing the third slurry onto a porous bed forming a fibre-containing layer, and drying and firing the layer.

Abstract: A conductive microporous sheet material comprises primary carbon fibres having a cross-sectional dimension of at least 1 ?m, secondary carbon fibres in the form of carbon nanofibres and a binding agent for binding said primary and secondary fibres. The material may be produced by a wet-laid non-woven (paper-making) process. The sheet material may be used as a gas diffusion layer for a fuel cell or an electrode material for a battery.

Abstract: A fuel cell gas diffusion substrate has primary fibres, secondary fibres and one or more thermoplastic polymers for binding the primary and secondary fibres, characterized in that the secondary fibers are in the form of carbon nanofibers, and a gas diffusion electrode and membrane electrode assembly prepared therefrom are disclosed.

Abstract: A conductive microporous sheet material comprises primary carbon fibres having a cross-sectional dimension of at least 1 &mgr;m, secondary carbon fibres in the form of carbon nanofibres and a binding agent for binding said primary and secondary fibres. The material may be produced by a wet-laid non-woven (paper-making) process. The sheet material may be used as a gas diffusion layer for a fuel cell or an electrode material for a battery.

Abstract: A fuel cell gas diffusion substrate comprising primary fibres, secondary fibres and one or more thermoplastic polymers for binding said primary and secondary fibres, characterised in that said secondary carbon fibres are in the form of carbon nanofibres, and a gas diffusion electrode and membrane electrode assembly prepared therefrom are disclosed.

Abstract: A flexible intumescent material which comprises inorganic fibers and flexible organic fibers together forming a predominantly fibrous matrix, an elastomeric binder and an intumescent substance and which has been compressed at a moisture content of less than 5% by weight. The intumescent material may be produced by wet laying an aqueous slurry of inorganic fibers, flexible organic fibers, the intumescent substance and the elastomeric binder onto a water-pervious support, withdrawing water from the slurry to form a sheet, drying the sheet to a moisture content of less then 5% by weight and then compressing the sheet material.