This test method is useful to measure the slow crack growth resistance of molded plaques of polyethylene materials at accelerated conditions such as 80°C, 2.4-MPa stress, and with a sharp notch.
The time to failure depends on the following test parameters: temperature; stress; notch depth; and specimen geometry. Increasing temperature, stress, and notch depth decrease the time to failure. Thus, in reporting the time to failure, all the conditions of the test must be specified.
1.1 This test method determines the resistance of polyethylene materials to slow crack growth under conditions specified within.
Note 1This test method is known as PENT (Pennsylvania Notch Test) test.
1.2 The test is generally performed at 80C and at 2.4 MPa, but may also be done at temperatures below 80C and with other stresses low enough to preclude ductile failure and thereby eventually induce brittle type of failure. Generally, polyethylenes will ultimately fail in a brittle manner by slow crack growth at 80C if the stress is below 2.4 MPa.
1.3 The test method is for specimens cut from compression molded plaques. See Appendix X1 for information relating to specimens from pipe.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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