EVALUATION OF INTERLAMINAR-TOUGHENED POLY(ETHER IMIDE)-MODIFIED EPOXYCARBON FIBER COMPOSITES/

Amorphous poly(ether imide) has been used as interlaminar toughening p articulate agent in laminated carbon fiber/epoxy composites. Mode I an d Mode II delamination fracture toughness was characterized using the double cantilever beam (DCB) and end-notched flexure (ENF) specimens. The delamination surface was examined using a scanning electron micros copy (SEM) to investigate relationships between the morphology and pro perties. The results revealed that the PEI-modified composites exhibit ed a significantly increased fracture toughness, which increased with the PEI content. G(IC) was improved from 165 to 540 J/m(2) (at 1 mm/mi n crosshead speed). G(IIC) was improved more significantly from 290 to 1300 J/m(2). It is believed that these values could be further improv ed if the processing cycle were to be optimized.