Provided are carbon fiber bundles which have high knot strength even if the single fiber fineness is large, and which have excellent handling properties and processability. The carbon fiber bundles have a single fiber fineness of 0.8-2.5 dtex, knot strength of 298 N/mm.sup.2 or greater. This method of producing carbon fibers having knot strength of 298 N/mm.sup.2 or greater involves a heat treatment step for heat treating, for 50-150 minutes, specific polyacrylonitrile-based precursor fiber bundles described in the description in an oxidizing atmosphere rising in temperature in the temperature range of 220-300 C.

A unitary graphene-based continuous graphitic fiber comprising at least 90% by weight of graphene planes that are chemically bonded with one another having an inter-planar spacing from 0.3354 to 0.4 nm and an oxygen content of 0.01 to 5% by weight, wherein the graphene planes are parallel to one another and parallel to a fiber axis direction and the graphitic fiber contains no core-shell structure, have no helically arranged graphene domains, and have a porosity level less than 5% by volume. This fiber can be produced by a continuous filament of graphene oxide gel having living graphene oxide molecules or functionalized graphene chains dissolved in a fluid medium. The filament is deposited onto a supporting substrate under a molecule-aligning stress condition along the filament axis direction and then subjected to drying and heating treatments.

A process of forming a fiber comprised of a plurality of bio-char particles, comprising: combining a portion of a polymer with a hemp derivative, said hemp derivative selected form a hemp carbon made by pyrolyzing a quantity of hemp stalk at between 1100-1500 C. to create a char; adding the char to a milling vessel and milling the char for a period of between 1 to 16 hours, and a full spectrum hemp extract, or combinations thereof, wherein the polymer and hemp derivative are extruded to form a fiber.

A molecularly imprinted polymer sensor for sensing a target molecule includes (a) a porous polymer film that is molecularly imprinted with a homolog of the target molecule and includes a conductive polymer having resistance sensitive to binding with the target molecule and a structural polymer providing porosity to the polymer film, and (b) interdigitated electrodes, located on a surface of the polymer film, for measuring a change in the resistance to sense said binding.

A process for preparing a PANOX fiber comprising: obtaining an acrylonitrile copolymer, wherein the copolymer contains at least about 2% by weight itaconic acid comonomer; forming a spin dope from the copolymer; wet spinning the spin dope to obtain gelled filaments; contacting the gelled filaments with ammonia activator in an aqueous imbibation bath; bundling the gelled filaments to obtain a fiber; removing solvent from the fiber; drawing the fiber; densifying the fiber by heating the fiber up to about 400 degrees C. for a time of about 15 minutes in a rapid densification zone; and withdrawing a PANOX fiber from the densification zone.

A method of forming carbon fibers having internal cavities. The method includes applying a polymer material to a tooling component to form carbon fiber precursor hollow tubes, oxidizing the carbon fiber precursor hollow tubes, and carbonizing the carbon fiber hollow tubes to form carbon fibers, each having a hollow inner cavity.

A carbon fiber bundle is obtained by filtering a spinning dope solution in which a polyacrylonitrile copolymer is dissolved in a solvent, at a predetermined filtration speed, using a filter medium having a predetermined particle retention and a filter basis weight, then spinning the filtered spinning dope solution to obtain a precursor fiber bundle for carbon fiber, and heat-treating the obtained precursor fiber bundle for carbon fiber at an appropriate temperature profile in an oxidizing atmosphere until reaching a predetermined density to obtain an oxidized fiber bundle, and then heat-treating the oxidized fiber bundle at a predetermined temperature in an inert atmosphere.

A composite Si-carbon fiber comprising a carbon matrix material with 1-90 wt % silicon embedded therein. The composite carbon fibers are incorporated into electrodes for batteries. The battery can be a lithium ion battery. A method of making an electrode incorporating composite Si-carbon fibers is also disclosed.

A composite rod for use in various applications, such as electrical cables (e.g., high voltage transmission cables), power umbilicals, tethers, ropes, and a wide variety of other structural members, is provided. The rod includes a core that is formed from a plurality of unidirectionally aligned fiber rovings embedded within a thermoplastic polymer matrix. The present inventors have discovered that the degree to which the rovings are impregnated with the thermoplastic polymer matrix can be significantly improved through selective control over the impregnation process, and also through control over the degree of compression imparted to the rovings during formation and shaping of the rod, as well as the calibration of the final rod geometry. Such a well impregnated rod has a very small void fraction, which leads to excellent strength properties. Notably, the desired strength properties may be achieved without the need for different fiber types in the rod.

A treated carbon fiber tensile cord for use in power transmission belts, hose, tires or other reinforced rubber products and the resulting product, which includes carbon fibers which are coated with a polymeric layer deposited and polymerized at atmospheric pressure in a plasma assisted chemical vapor deposition process. A suitable polymeric layer is compatible with the intended matrix which the cord will reinforce. For a rubber belt, the coating is compatible with the rubber composition of the belt body or an adhesion gum or adhesive such as RFL which surrounds the cord. For RFL/rubber systems and cast polyurethane elastomers, a suitable polymer is the APP reaction product of a vinyl carboxylic acid or an ester or amide thereof. Suitable carboxylic acids include acrylic acid and methacrylic acid. Various esters and amides of vinyl carboxylic acid are also suitable, such as 2-hydroxyethyl methacrylate, N-isobutoxymethyl acrylamide, and N-hydroxyethyl acrylamide.