ASTM D7744/D7744M-20

5.1 The levels of tensile properties obtained when testing high performance polyethylene films are dependent on the age and history of the specimen and on the specific conditions used during the test. Among these conditions are rate of stretching, type of clamps, gauge length of specimen, temperature and humidity of the atmosphere, rate of airflow across the specimen, and temperature and moisture content of the specimen. Testing conditions accordingly are specified precisely to obtain reproducible test results on a specific sample.

5.2 Breaking force is used in engineering calculations when designing various types of products. When needed to compare intrinsic strength characteristics, films of different sizes or different types of film, breaking tenacity is very useful because, for a given type of film, breaking force is approximately proportional to linear density.

5.3 Elongation of film is taken into consideration in the design and engineering of reinforced products because of its effect on uniformity of the finished product and its dimensional stability during service.

5.4 The FASE is used to monitor changes in characteristics of the material during the various stages involved in the processing.

5.5 Modulus is a measure of the resistance of film to extension as a force is applied. Although modulus may be determined at any specified force, initial modulus is the value most commonly used.

5.6 Work-to-break is dependent on the relationship of force to elongation. It is a measure of the ability of a textile structure to absorb mechanical energy. Toughness at break is work-to-break per unit mass.

5.7 Shape, size, and internal construction of the end-product can have appreciable effect on product performance. It is not possible, therefore, to evaluate the performance of end product in terms of the reinforcing material alone.

5.8 If there are differences of practical significance between reported test results for two laboratories (or more), comparative tests should be performed to determine if there is a statistical bias between them, using competent statistical assistance. As a minimum, test samples should be used that are as homogeneous as possible, that are drawn from the material from which the disparate test results were obtained, and that are randomly assigned in equal numbers to each laboratory for testing. Other materials with established test values may be used for this purpose. The test results from the two laboratories should be compared using a statistical test for unpaired data, at a probability level chosen prior to the testing series. If a bias is found, either its cause must be found and corrected, or future test results must be adjusted in consideration of the known bias.

1.1 These test methods cover the tensile testing of high performance polyethylene films. The methods include testing procedure only and include no specifications or tolerances.

1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.

1.3 This standard includes the following test methods:

1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.