A composite fiber for use in additive manufacturing such as fused filament fabrication is described along with methods of its construction and use. The composite fiber includes a single continuous fiber (e.g., a continuous carbon roving) and a polymer (e.g., a high glass transition polymer) in intimate contact. The composite fiber is formed through immersion of the continuous fiber in a series of two or more solutions that together include monomer(s), catalysts, or other materials for generating the polymer as the continuous fiber moves through the solutions.

A unidirectional laminate comprising a fiber reinforced composite material having a main relaxation temperature (Tα) in a range between about 110° C. and 140° C. The composite comprises a plurality of unidirectional reinforcement fibers coated with a sizing composition and a matrix resin. The unidirectional laminate has a tensile modulus of at least 45 GPa at a fiber volume fraction greater than or equal to 50% and fatigue mechanical performance of at least 450 MPa at 1 MM cycles, measured according to ASTM E 739-91.

A unidirectional laminate comprising a fiber reinforced composite material having a main relaxation temperature (Tα) in a range between about 110° C. and 140° C. The composite comprises a plurality of unidirectional reinforcement fibers coated with a sizing composition and a matrix resin. The unidirectional laminate has a tensile modulus of at least 45 GPa at a fiber volume fraction greater than or equal to 50% and fatigue mechanical performance of at least 450 MPa at 1 MM cycles, measured according to ASTM E 739-91.

The present application relates to a fiber reinforced thermoplastic composite sheet and a method for preparing the same. The fiber reinforced thermoplastic composite sheet has on its surface a marble texture effect obtained by laminating cut pieces of a continuous fiber reinforced thermoplastic composite unidirectional tape, wherein the fibers and the resin used in the continuous fiber reinforced thermoplastic composite unidirectional tape have different colors. The thermoplastic composite sheet may be prepared using a simple and quick method, and meet individual requirements of surface appearance of the final product.

The present application relates to a fiber reinforced thermoplastic composite sheet and a method for preparing the same. The fiber reinforced thermoplastic composite sheet has on its surface a marble texture effect obtained by laminating cut pieces of a continuous fiber reinforced thermoplastic composite unidirectional tape, wherein the fibers and the resin used in the continuous fiber reinforced thermoplastic composite unidirectional tape have different colors. The thermoplastic composite sheet may be prepared using a simple and quick method, and meet individual requirements of surface appearance of the final product.

A composite material includes a carbon fiber bundle including a plurality of continuous carbon fibers; and a structure, formed on each of the carbon fibers, including a plurality of carbon nanotubes and having a network structure in which the carbon nanotubes are in direct contact with each other and in which the carbon nanotubes directly adhere to surfaces of the carbon fibers. The carbon nanotubes have a bent shape including a bent portion, and a thickness of the structure is within a range of 50 nm to 200 nm.

A method for forming a composite part involves forming a layup comprising (a) preforms/flat form-factor feedstock, either of which includes a plurality of fibers and a matrix precursor, and (b) a differential-melt polymer. The matrix precursor and the differential-melt polymer differ as to at least one of thermal properties and rheological properties. The layup is subjected to controlled application of heat and pressure to melt the matrix precursor and differential-melt polymer. The polymers are then cooled to form a composite part that displays properties attributable to all the constituents. As a function of a variety of factors, the resulting part can be homogenous or heterogenous, and the properties can be localized or global throughout the part.

The invention relates to an impregnated yarn, a ribbed thin-walled composite product comprising such an impregnated yarn, and a method of making them. Such an impregnated yarn (10d; 10e) comprises at least two continuous strands (10a; 10b) comprising plant fibers (11), said strands (10a; 10b) being impregnated with thermoplastic material (12a) in at least 60% of their volume, each of said strands (10a; 10b) being individually twisted and all of said strands (10a; 10b) also being twisted in a configuration (10d) held by the thermoplastic material (12a).

A composite prepreg and a fiber-reinforced plastic molded body are described that are excellent in secondary weldability with another member and exhibit excellent handleability and reinforcing characteristics, where the composite prepreg in which reinforcing fibers are impregnated with a thermoplastic resin and a thermosetting resin, and a thermoplastic resin layer and a thermosetting resin layer that form an interface and joined to each other are formed, wherein the thermoplastic resin layer is present on at least one surface of the composite prepreg, and the thermoplastic resin layer contains continuous reinforcing fibers.

A method for improving the translation efficiency of fiber strength into composite strength is provided. A single unidirectional tape, single unidirectional fiber web or a stack of unidirectional web/unidirectional tape plies formed from partially oriented fibers/tapes is primed under mild conditions followed by subjecting the primed plies to an axial extension stress in the axial fiber direction of each fiber ply by passage through a compression apparatus. The axial extension stress extends the fibers, strengthening them, while also compacting the plies together and thereby forming a composite having improved strength. Production yield is improved by avoiding maximal fiber stretching and thereby avoiding typical manufacturing loss, and low weight composite armor having increased strength is achieved.