Abstract: An object of the present invention is to provide a carbon fibrous structure having good dispersibility and small variations in electrical conductivity, etc., and being capable of improving physical properties such as electrical properties, mechanical properties and thermal properties by a small amount addition thereof without impairing properties of a matrix.

Abstract: [Problems] To provide a vapor-grown carbon fiber aggregate, wherein the carbon fiber has a structure of two or more tubular graphene layers and of which the central portion in cross section of the fiber is hollow, has a little unevenness in the structure and exhibits excellent electric conductivity. [Means for Solution] A vapor-grown carbon fiber aggregate, wherein the carbon fiber has a structure of two or more tubular graphene layers and of which the central portion in cross section of the fiber is hollow, the average outer fiber diameter of the carbon fibers is from 10 to 300 nm, and not less than 70% of the whole number of the carbon fibers have hollow diameters of from 2 to 20 nm and hollow diameter/outer fiber diameter ratios of from 1.4 to 20%.

Abstract: Carbon fibrous aggregator obtained by a chemical vapor phase growing method, which comprises plural granular parts, and plural carbon fibers which are mutually independently extended outwardly from their respective granular parts so that each granular part is associated with two or more of carbon fibers, wherein the carbon fibers show a three dimensional expansion in all; and which show a three dimensional network structure of the carbon fibers at least in a part by a state that at least a part of the plural carbon fibers extended from one granular part is linked with another granular part; wherein mean length of carbon fibers which link two granular parts together is of 3.0-20.0 ?m, and wherein a coefficient of variation, CV, ((standard deviation/mean value)×100) which is obtained on a determination of outer diameter distribution of the carbon fibers which constitute the aggregator of carbon fiber is not more than 30%.

Abstract: Disclosed is a carbon fibrous aggregator obtained by a chemical vapor phase growing method, which comprises plural granular parts, and plural carbon fibers which are mutually independently extended outwardly from their respective granular parts so that each granular part is associated with two or more of carbon fibers, wherein the carbon fibers show a three dimensional expansion in all; and which show a three dimensional network structure of the carbon fibers at least in a part by a state that at least a part of the plural carbon fibers extended from one granular part is linked with another granular part; wherein mean length of carbon fibers which link two granular parts together is of 3.0-20.0 ?m, and wherein a coefficient of variation, CV, ((standard deviation/mean value)×100) which is obtained on a determination of outer diameter distribution of the carbon fibers which constitute the aggregator of carbon fiber is not more than 30%.

Abstract: An object of the present invention is to provide a carbon fibrous structure having good dispersibility and small variations in electrical conductivity, etc., and being capable of improving physical properties such as electrical properties, mechanical properties and thermal properties by a small amount addition thereof without impairing properties of a matrix.