Graphite fiber of lamination cross section structure and melting spinning method for graphite fiber

Abstract

The invention provides a graphite fiber of a lamination cross section structure and a melting spinning method for the graphite fiber. The method comprises the following steps that 1, intermediate-phase asphalt is adopted for melting spinning to obtain a fiber protofilament; the cross section of a spinneret orifice used for melting spinning is rectangular, the long edge of a spinneret orifice outlet is provided with an outlet chamfer, and the inner surface of the spinneret orifice is plated with a layer of metal coating with nickel or silver or platinum; 2, the fiber protofilament is subjectedto non-melting carbonization and graphitization in sequence to obtain the graphite fiber of the lamination cross section structure. After the prepared fiber protofilament with an oval cross section issubjected to non-melting carbonization and graphitization, a graphite flake layer of the fiber protofilament is approximately parallel to the direction of the long edge of the cross section of the fiber, La and Lc of graphite microcrystals can sufficiently develop, the graphite flake layer has few and compact wrinkles, and the heat conductivity of the finally-obtained graphite fiber can reach 800-1,100 W / (m.K).

Description

technical field [0001] The invention belongs to the technical field of polymer fiber materials, and in particular relates to a graphite fiber with a laminated section structure and a melt spinning method thereof. Background technique [0002] Carbon fiber is a fibrous carbon material with a lower density than metal aluminum, but higher strength than steel, and has the characteristics of corrosion resistance and high modulus. Graphite fiber generally refers to carbon fiber with a carbon content of more than 99%. Compared with carbon fiber, graphite fiber not only has a high carbon content, but also has a high tensile modulus, and also has a small thermal expansion coefficient, good thermal stability, and stable dimensions. Excellent performance, so it is used to manufacture rigid, thin and dimensionally stable composite components, which are widely used in spacecraft and aerospace fields. The outstanding characteristics of mesophase pitch-based graphite fibers are their extr...

AI Technical Summary

Problems solved by technology

At present, the cross-section of pitch-based carbon fiber with high thermal conductivity is generally approximately circular, and the graphite microcrystalline structure of the cross-section is radial, onion-skin-like, laminated, composite or random-layered, etc. The laminated structure is conducive to the improvement of thermal conductivity. However, in the current carbon fibers with approximately circular cross-sections, the graphite sheets in the laminated structure are distributed perpendicular to the long side of the fiber cross-section, which restricts the growth of the microcrystalline structure, which in turn restricts the improvement of the thermal conductivity of carbon fibers.

Some scholars proposed a melt-spinning method with rectangular spinneret holes, and ribbon fibers were obtained by adjusting the aspect ratio of the holes, but the graphite sheets in the microcrystalline structure of the cross-section still showed a structure arranged perpendicular to the long side of the fiber cross-section , which restricts the growth of microcrystalline structure and the improvement of carbon fiber thermal conductivity to a certain extent, and the ribbon fiber is also not conducive to the subsequent application of composite materials.

Images