THERMAL DEGRADATION EFFECT ON THE FRACTURE TOUGHNESS OF GLASS FIBER REINFORCED UNSATURATED POLYESTER RESIN COMPOSITE

Abstract

AbstractSamples of FRP prepared by applied unsaturated polyester resin as matrix reinforced by one layerwoven glass fiber( 0º/90º), using hand lay up method. The prepared samples are subjected tothermal aging at 85 º C for different time in dryer oven up to 1200 hrs time and tested byunnotched sample impact tester to obtained the fracture toughness , polynomial relationshape oforder 5 found between Gc and Aging time decreasing Gc strongly to lower value .The Stress straintests for aged to specific time and without aging samples by tensile test show that sample agedthermally tend to brittle behavior and lost its mechanical properties as aging time increase, whilesample without aging show ductile behavior . FTIR analysis show decomposition of the polyesterby creating new free radical and observed new peak wave number in transmtion spectra due tofiber crystallization.