Effect of Ti(+), Ar(+), N(+), and He(+) ion implantation on aramid fiber adhesive properties

An investigation is conducted of the ways in which the effects of ion irradiation can be exploited to modify fiber-matrix interfacial properties in aramid fiber-reinforced epoxy-matrix composites. The beneficial effects of such processing proceed from such factors as the production of nonequilibrium conditions in shallow, controllable surface layers without sharp interfacial gradients, and the ability of the irradiation to alter the physical morphology of the free surface. Positive ions of Ti, Ar, He, and N were implanted at 30-400 keV in polyaramid fibers, at dosage levels in the 10 to the 12th to 10 to the 15th ions/sq cm range. While large improvements in interfacial shear strength properties were not obtained, the effects of ion irradiation on surfaces with pronounced skin-core structure are revealed in considerable detail. 9 refs