Improvement of the interfacial adhesion between Kevlar fiber and resin by using R-F plasma

Abstract

The interfacial adhesion between fiber and matrix has a significant effect on the overall performance of a composite. The necessity of binding the fibers together in a structural composite creates the need for an enhanced interfacial bond between fibers and matrix. One possibility to change the fiber/matrix bond in composite materials is to modify the surface of the reinforcing fiber. One technology useful for this purpose is plasma treatment. This paper discusses optimizing R-F plasma polymerization of allylamine onto Kevlar 29 and KM2 fibers. The treatment was carried out in two steps. First, the fiber was treated with Argon; second, the fiber was treated by allylamine. A method was found such that, under such optimum treatment conditions, the plasma treatment does not adversely affect the mechanical properties of the fibers. This allows flexibility in the tailoring of interfacial properties to optimize the energy absorption capability of the composites. A method was also found that increases interfacial adhesion between PPTA fiber (Kevlar) filament and the matrix as the thickness of the plasma allylamine coating increases.