There is provided a random mat including carbon fibers having an average fiber length of from 3 mm to 100 mm and a thermoplastic resin, wherein a fiber areal weight of the carbon fibers is from 25 to 10,000 g/m.sup.2, a proportion of carbon fiber bundles (A) constituted by single carbon filaments of a critical single fiber number or more defined by the formula (1) to the total amount of fibers in the random mat is from 40 to 99 Vol %, and an average number (N) of fibers in the carbon fiber bundles (A) satisfies the formula (2):
critical single fiber number=600/D(1)
2.010.sup.5/D.sup.2N<8.010.sup.5/D.sup.2(2) wherein D is an average fiber diameter (m) of carbon fibers.

A loom system for making a fibrous preform may comprise a base, a bedplate coupled to the base, wherein the bedplate is configured to rotate about an axis of rotation, and an air entangling module coupled to the base. The air entangling module may comprise an air entangling head coupled to an outer support and an inner support, wherein the air entangling head is configured to apply a jet of air toward the bedplate at an entangling zone. The air entangling head may have freedom of motion along the outer support and the inner support, and may be configured to rest on top of a fibrous layer.

A random mat contains reinforcing fibers having an average fiber length of 3 to 100 mm and a thermoplastic resin, the reinforcing fiber contains reinforcing fiber bundle (A) defined as the bundle composed of the reinforcing fibers of a critical number of single fiber (defined by the following formula (1)) or more, an average thickness of the reinforcing fiber bundles (A) is 100 m or less, and the number (n) of the reinforcing fiber bundles (A) per unit weight (g) of the reinforcing fibers satisfies the following formula (I): Critical number of single fiber=600/D (1) (wherein D is the average fiber diameter (m) of the reinforcing fiber), and 0.6510.sup.4/L<N (I) (wherein L is the average fiber length (mm) of the reinforcing fiber).

A random mat contains reinforcing fibers having an average fiber length of 3 to 100 mm and a thermoplastic resin, the reinforcing fiber contains reinforcing fiber bundle (A) defined as the bundle composed of the reinforcing fibers of a critical number of single fiber (defined by the following formula (1)) or more, an average thickness of the reinforcing fiber bundles (A) is 100 m or less, and the number (n) of the reinforcing fiber bundles (A) per unit weight (g) of the reinforcing fibers satisfies the following formula (I): Critical number of single fiber=600/D (1) (wherein D is the average fiber diameter (m) of the reinforcing fiber), and 0.6510.sup.4/L<N (I) (wherein L is the average fiber length (mm) of the reinforcing fiber).

A method and apparatus for fabricating a short length carbon fiber preform with a through thickness reinforcement is disclosed herein. The starting media for fabricating a net shape (e.g., annular disc) may meet specific requirements including a sufficient fiber volume and a binding mechanism compatible with the needle-punching process.

A method and apparatus for fabricating a short length carbon fiber preform with a through thickness reinforcement is disclosed herein. The starting media for fabricating a net shape (e.g., annular disc) may meet specific requirements including a sufficient fiber volume and a binding mechanism compatible with the needle-punching process.

The invention relates to electrospun three-dimensional (3D) nanofibrous scaffolds (with controllable porosities as high as about 96%) and methods of preparing the same. The electrospun 3D scaffolds possess interconnected and hierarchically structured pores with sizes ranging from tens of nanometers to hundreds of micrometers. In embodiments, the 3D scaffolds can be biocompatible and/or biodegradable. In some embodiments, the 3D scaffolds can be conductive. In some embodiments, the 3D scaffolds can contain bioactive species.

A method for arranging nanotube elements within nanotube fabric layers and films is disclosed. A directional force is applied over a nanotube fabric layer to render the fabric layer into an ordered network of nanotube elements. That is, a network of nanotube elements drawn together along their sidewalls and substantially oriented in a uniform direction. In some embodiments this directional force is applied by rolling a cylindrical element over the fabric layer. In other embodiments this directional force is applied by passing a rubbing material over the surface of a nanotube fabric layer. In other embodiments this directional force is applied by running a polishing material over the nanotube fabric layer for a predetermined time. Exemplary rolling, rubbing, and polishing apparatuses are also disclosed.

A method for arranging nanotube elements within nanotube fabric layers and films is disclosed. A directional force is applied over a nanotube fabric layer to render the fabric layer into an ordered network of nanotube elements. That is, a network of nanotube elements drawn together along their sidewalls and substantially oriented in a uniform direction. In some embodiments this directional force is applied by rolling a cylindrical element over the fabric layer. In other embodiments this directional force is applied by passing a rubbing material over the surface of a nanotube fabric layer. In other embodiments this directional force is applied by running a polishing material over the nanotube fabric layer for a predetermined time. Exemplary rolling, rubbing, and polishing apparatuses are also disclosed.

Provided are a method for producing a carbon fiber bundle composite and a carbon fiber bundle composite. The method contains a step of mixing carbon fiber fluff made of short carbon fibers and a molten resin containing an epoxy resin component to obtain a carbon fiber bundle containing the molten resin, a step of solidifying the molten resin, and a step of mixing at least one type of epoxy curing agent into the molten resin. The carbon fiber bundle composite contains a plurality of short carbon fibers forming the bundle and an uncured solid epoxy resin composition. The positions of the tips of the short carbon fibers are uneven at each end of the bundle; and the uncured solid epoxy resin composition contains at least one type of epoxy curing agent.