THE EFFECT OF TEMPERATURE ON THE SINGLE-FIBER FRAGMENTATION TEST WITHCOATED CARBON-FIBERS

In this study AS4 carbon fibers were coated with poly(hexamethylene ad ipamide) by two different coating techniques. The glass transition tem perature of the interphase was tailored to investigate its influence o n the micromechanical behavior. The critical length was measured by me ans of the single-fiber fragmentation test over a wide range of temper atures. Experimental results reveal the sensitivity of the critical as pect ratio of the fiber to the glass transition temperature of the coa ting and also verify the existence of an epoxy interphase of reduced g lass transition temperature near the fiber surface. The effect of the thickness of the coating on the critical aspect ratio of the fiber was also investigated. An increase in the thickness of the polyamide coat ing results in poorer adhesion. (C) 1998 Elsevier Science Ltd. All rig hts reserved.