Fracture toughness of vinyl ester composites cured by microwave irradiation: preliminary results

Abstract

The shrinkage of vinyl ester particulate composites has been reduced by curing the resins under microwave conditions. The reduction in the shrinkage of the resins by microwaves will enable the manufacture of large vinyl ester composite items possible (Ku et al., 2002a; 2002b; 2003a; 2003b). The impact strength of the vinyl ester composite components cured under microwave was reduced only by 1 percent when tested by drop weight impact tests. This project is to investigate the difference in fracture toughness between microwave cured vinyl ester particulate composites and those cured under ambient conditions. Short bar method of fracture toughness measurement was used to perform the tests. The results show that the difference in the fracture toughness is minimal between the ambient cured and microwaved-cured samples, provided the power level and duration of microwave irradiation are properly and optimally selected.