1.1 本试验方法包括通过使用超声波设备测定聚乙烯密度。 1.2 本试验方法基于聚乙烯的非晶相和结晶相在超声波作用下的不同行为。聚乙烯应被视为一种复合结构，其中高密度结晶区域由低密度非晶材料连接。晶体与非晶材料的比率决定了材料的最终密度。非晶相和晶相在声波传播方面表现出非常不同的行为。复合材料中的传播特性将取决于两相的相对数量（结晶度）。 1.3 通过试验方法测量，无机材料增加了密度 D792 和 D1505 ，但它们对超声密度几乎没有影响。超声波测量基本上是基础树脂密度。 1.4 以国际单位制表示的数值应视为标准。括号中给出的值仅供参考。 1.5 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。 注1: 没有已知的ISO等效于本标准。 1.6 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 聚乙烯的密度是一种方便测量的特性，通常可用作跟踪样品中物理变化的手段、指示样品之间的均匀性以及识别手段。 4.2 本试验方法旨在产生精度为±0.08的结果 % 或者更好。

1.1 This test method covers the determination of the density of polyethylene through the utilization of ultrasound equipment. 1.2 This test method is based on the distinct behaviors of the amorphous and crystalline phases of polyethylene in response to ultrasound. Polyethylene shall be viewed as a composite structure where high-density crystalline regions are connected by lower-density amorphous material. The ratio of crystalline to amorphous material determines the final density of the material. The amorphous and crystalline phases exhibit very distinct behaviors with regard to the propagation of sound waves. The propagation characteristics in the composite will depend on the relative amount of the two phases (the degree of crystallinity). 1.3 Inorganic materials increase density as measured by Test Methods D792 and D1505 , but they have little or no effect on ultrasonic density. The ultrasonic measurement is basically a base resin density. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.5 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. Note 1: There is no known ISO equivalent to this standard. 1.6 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 density of polyethylene is a conveniently measurable property which is frequently useful as a means of following physical changes in a sample, as an indication of uniformity among samples, and as a means of identification. 4.2 This test method is designed to yield results with a precision of ±0.08 % or better.