Method for constructing multi-scale flexible-rigid interface layers on surfaces of carbon fibers for synchronous reinforcement and toughening

Abstract

The invention discloses a method for constructing multi-scale flexible-rigid interface layers on the surfaces of carbon fibers for synchronous reinforcement and toughening. The method comprises the following steps: cleaning and drying the carbon fibers; putting the cleaned and dried carbon fibers and excessive nitric acid into a reaction container for oxidation treatment to obtain the carbon fibers with a large number of carboxyl groups on the surfaces; jointly constructing multi-scale flexible-rigid interface layer structures on the surfaces of the fibers by using an aqueous solution of branched polyethyleneimine and a suspension of a metal-organic framework compound; and cleaning and drying the modified carbon fibers. According to the method, the advantages of the branched polyethyleneimine and the metal-organic framework compound are combined, and the interface bonding performance between the carbon fibers and resin matrices is effectively enhanced through the multi-scale flexible-rigid interface layer structures and chemical reactions between the carbon fibers and the resin matrices.

Description

technical field [0001] The invention belongs to the technical field of carbon fiber surface modification, and in particular relates to a method for constructing a multi-scale soft-rigid interface layer on the surface of carbon fiber to simultaneously strengthen and toughen. Background technique [0002] In view of the fact that carbon fiber has high strength, high modulus, low weight and excellent environmental stability, its reinforced epoxy resin-based composites are widely used in aviation, ships, automotive energy and other fields. On the basis of meeting the requirements of mechanical properties Significantly reduced weight. [0003] However, due to the smooth, non-polar and chemically inert surface of carbon fiber, the interface compatibility with the resin matrix is ​​poor, and the existence of a weak interface can easily cause irreversible damage to the material; at the same time, the modulus of carbon fiber is high, and the toughness of epoxy resin is insufficient, ...

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Problems solved by technology

[0006] The purpose of the present invention is to solve the problem that the structural strength and toughness of the interface layer between carbon fiber and resin are difficult to improve at the same time, and to provide a method for constructing a multi-scale soft-rigid interface layer on the surface of carbon fiber to simultaneously strengthen and toughen. Based on the respective advantages of polyethyleneimine and metal-organic framework compounds, the interfacial bonding performance between carbon fiber and resin is effectively strengthened through the chemical reaction between the multi-scale "flexible-rigid" interface layer structure and the carbon fiber and resin matrix. At the same time, the use of branched polyethyleneimine can produce large plastic deformation and the metal-organic framework compound’s own energy absorption effect simultaneously improves the interfacial fracture toughness of the composite material, which has a certain effect on the construction of the interface layer of carbon fiber reinforced resin matrix composites. Its guiding significance further expands its application in high-speed transportation and other fields

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