Effect of moulding temperature on flexure, impact strength and interlaminar fracture toughness of CF/PEI composite

The effects of processing conditions on the mechanical properties of a CF/PEI woven fabric composite have been investigated. A compression moulding procedure using a hot press was applied to simulate the effects of various processing conditions. The mechanical properties of the CF/PEI composite were characterised by flexure, impact strength and interlaminar fracture tests in relation to the consolidation quality. Consolidation quality was studied through void content and density measurement. The results indicated that the consolidation quality of the composites was highly dependent on the processing temperature. The flexure properties, Mode I and Mode II fracture toughness for crack initiation and Mode II interlaminar fracture growth resistance correlated directly with consolidation quality. However, the Charpy impact strength and Mode I interlaminar fracture growth resistance both increased as the void content was increased because of a ''multiple-crack'' failure mechanism.