MECHANICAL AND FRACTURE PROPERTIES OF DIETHYLENE GLYCOL BIS(ALLYL CARBONATE) RESINS

Mechanical properties and fracture tests were conducted on the thermoset diethylene glycol bis(allyl carbonate). It was found that both sigma(y) and E increase as the testing rate increases. Crack propagation which is unstable (stick-slip) at a low loading rate changes to stable propagation as the loading rate is raised. Linear elastic fracture mechanics concepts were employed to analyse the stress intensity factors versus the yield stress. It is suggested that the stick-slip behaviour is due to blunting of the crack, which is controlled by the yield behaviour of the resin. It is shown that a critical stress of the order of five times the yield stress must be achieved at a critical distance ahead of the crack tip. Fracture surfaces were analysed using scanning electron microscopy and optical microscopy. No indication of crazing was detected.