The strain in the test environmental stress cracking of plastics

An investigation was carried out to determine the appropriate values of strain to be exerted in the test for environmental stress cracking of different kinds of polymeric materials. It was found that for the brittle plastics the elastic region on the stress-strain curve is the best selection; for toughened plastics the strain should be selected in the plastic region; for polycarbonate, which can crack easily in a chemical medium, a strain below the yield point is suitable. These results could be used as a reference in the application of test method Plastics-Determination of environmental stress cracking (ESC)-Ball or pin impression method. (C) 2002 Elsevier Science Ltd. All rights reserved.