1.1 本规程涵盖降解终点的确定 （脆点） 适用于小于1.0 mm（0.04 in.）的可降解聚乙烯/聚丙烯薄膜和片材厚的本规程不用于测定聚乙烯/聚丙烯薄膜或片材的降解速率或程度，而是用于评估在某些条件下降解过程中何时达到脆性点。如果希望在降解过程中监测拉伸伸长率（例如当拉伸伸长率显著大于5 %), 试验方法 D882 建议使用。这种做法不应被视为确定降解终点的唯一方法。 1.2 塑料的拉伸性能1.0 mm（0.04 in.）或更大的厚度应根据试验方法确定 D638 . 1.3 使用静态称重恒速抓取分离试验。该程序采用固定样品的夹具和静态称重传感器的恒定分离速率。 注1: 该程序基于使用夹点分离作为扩展措施；然而，使用精确到±1.0的扩展指示器的可取性 % 或试验方法中规定的更好 D638 程序中包含了使用此类仪器的规定。 1.4 该程序已成功确定乙烯-一氧化碳共聚物的降解终点，并在循环试验中成功筛选了另外两种添加剂型聚乙烯。 1.5 以国际单位制表示的数值应视为标准。括号中的值仅供参考。 1.6 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.7 没有等效的ISO标准。 1.8 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 4.1 本规程确定的拉伸伸长率特性对于可降解材料的表征具有价值。拉伸延伸性能可能随试样厚度、制备方法、测试速度、使用的夹具类型和测量测试延伸的方式而变化。因此，如果需要精确的比较结果，则必须仔细控制这些因素。 4.2 可以使用拉伸伸长率特性为研发和工程设计以及质量控制规范提供数据。 然而，对于与所采用测试的负载时间尺度相差很大的应用而言，此类测试的数据并不重要。 4.3 撕裂破坏的材料提供的异常数据无法与正常破坏的数据进行比较。 4.4 在继续使用本试验方法之前，需要参考被测材料的规范。材料规范中涵盖的任何试样制备、调节、尺寸或测试参数或其组合应优先于本试验方法中提及的。如果没有材料规范，则默认条件适用。

1.1 This practice covers the determination of a degradation-end point (a brittle point) for degradable polyethylene/polypropylene films and sheeting less than 1.0 mm (0.04 in.) thick. This practice is not intended for determination of the rate or degree of degradation of a polyethylene/polypropylene film or sheet, but rather, to assess when in the course of its degradation under some condition, a brittle point is reached. If one wishes to monitor tensile elongation during the degradation process (such as when the tensile elongation is significantly greater than 5 %), Test Method D882 is recommended. This practice is not to be considered the only way of determining a degradation-end point. 1.2 Tensile properties of plastics 1.0 mm (0.04 in.) or greater in thickness shall be determined in accordance with Test Method D638 . 1.3 Use a static weighing-constant rate of grip separation test. This procedure employs a constant rate of separation of the grips holding the sample and a static load cell. Note 1: This procedure is based on the use of grip separation as a measure of extension; however, the desirability of using extension indicators accurate to ±1.0 % or better as specified in Test Method D638 is recognized, and a provision for the use of such instrumentation is incorporated in the procedure. 1.4 This procedure has been successful for determining the degradation end point of ethylene-carbon-monoxide copolymers and has screened successfully two other additive-type polyethylenes in a round robin test. 1.5 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only. 1.6 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. 1.7 There is no equivalent ISO standard. 1.8 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. ====== Significance And Use ====== 4.1 The tensile elongation property determined by this practice is of value for the characterization of degradable materials. It is possible that the tensile elongation property will vary with specimen thickness, method of preparation, speed of testing, type of grips used, and manner of measuring test extension. Consequently, where precise comparative results are desired, these factors must be carefully controlled. 4.2 It is acceptable to use the tensile elongation property to provide data for research and development and engineering design as well as quality control specifications. However, data from such tests cannot be considered significant for applications differing widely from the load-time scale of the test employed. 4.3 Materials that fail by tearing give anomalous data that cannot be compared with those from normal failure. 4.4 Before proceeding with this test method, reference needs to be made to the specifications of the material being tested. Any test specimen preparation, conditioning, dimensions, or testing parameters or a combination thereof, covered in the material specifications shall take precedence over those mentioned in this test method. If there are no material specifications, then the default conditions apply.