Modification method of aramid fiber in supercritical CO2 by surface grafting polymerization

Abstract

The invention relates to a modification method of aramid fiber in supercritical CO2 by surface grafting polymerization. The method comprises the steps of: (1) cleaning aramid fiber surface with acetone and vacuum-drying fiber; (2) adding monomers and an initiator to a reaction vessel, then adding the aramid fiber, closing the reaction vessel, removing air, introducing CO2 into the reaction vessel at the temperature lower than the decomposition temperature of the initiator so that the system is in a supercritical CO2 state, swelling and heating for polymerizing the monomers to obtain surface-polymerization-modified aramid fiber, wherein the aramid fiber does not contact the monomers and the initiator; and (3) cleaning the surface-polymerization-modified aramid fiber with acetone until constant weight, and finally vacuum-drying the fiber. According to the invention, the method is simple in operation, economical, environmentally friendly and controllable in grafting ratio; and the obtained modified aramid fiber has rough surface due to the existence of the polymer, so that the adhesion and compatibility between the fiber and a composite material substrate are improved and the application of the fiber as a composite material reinforcing agent is facilitated.

Description

technical field [0001] The invention belongs to the field of modification of aramid fiber, in particular to a kind of aramid fiber modified in supercritical CO 2 Surface graft polymerization modification method in . Background technique [0002] Aramid fiber can be roughly divided into poly-m-phenylene isophthalamide fiber (referred to as meta-aramid fiber), poly-para-phenylene terephthalamide fiber (referred to as para-aramid fiber) and heterocyclic aromatic polyamide fiber. Amide fiber (referred to as aramid fiber III) and other varieties. Because aramid fibers have the characteristics of ultra-high modulus, high strength, high temperature resistance, and light weight, they are widely used in aerospace, military clothing, and material reinforcement. Since aramid fiber is formed by rigid molecular chains, it has a unique "skin-core" structure. The rod-like molecules in the core are arranged in parallel through hydrogen bonds, and the rigid molecular chains with high cryst...

AI Technical Summary

Problems solved by technology

Although the two solution modification methods can modify the surface of aramid fibers, they have disadvantages such as complicated operation, toxic solvent, pollution, and poor control of the reaction, so they have not been applied on a large scale.

There are few studies on the modification of aramid fibers by solid-phase grafting, and there are disadvantages such as high reaction temperature, uncontrollable reaction, complicated operation, and low inoculation rate. Generally, it is not used to modify aramid fibers.

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