Examination of the thermophysical bond of insert-molded PC/C fiber composites

The adhesive strength of a thermophysical bond between two polymers has bee n examined using fracture mechanics. Bimaterial composite specimens were co nstructed by injecting C fiber polyetheretherketone (PEEK) into a mold cont aining one-half of a polycarbonate (PC) dogbone. The resulting series speci mens were notched at the interface and tested in tension. Adhesion of the t wo materials was reasonably good, as demonstrated by fracture surfaces that showed a mixture of PC and C fiber PEEK fragments. Interfacial fracture en ergy of the composite was approximately 1.5 kJ/m(2), which is comparable to the cohesive strength of amorphous commodity polymers. Variations in test speed (below the glass transition temperature of the two components, approx imately 140 degrees C) had no appreciable affect on stiffness or fracture e nergy. However, fracture energies decreased slightly as temperature increas ed. (C) 2000 Kluwer Academic Publishers.