1.1 本试验方法涵盖大多数类型的聚乙烯、由比丙烯更长的乙烯和α-烯烃共聚单体组成的乙烯塑料，以及上述任何比例的混合物。 1.2 以国际单位制表示的数值应视为标准。 1.3 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。 具体危害说明见第节 8. . 注1: 本标准没有已知的ISO等效标准。 1.4 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====== 5.1 有三种类型的烯烃基团以足够的浓度存在，以保证考虑，其中一种或多种通常可以在任何聚乙烯中找到。这三种类型是trans- 乙烯，R-CH=CH-R ′ ，有时称为反式内不饱和；亚乙烯或悬垂亚甲基，RR ′ C-CH2；乙烯基不饱和，R-CH=CH2，也称为末端不饱和。 5.2 这些基团的类型和数量会影响树脂的化学和物理性能。有关其存在的信息也可用于表征或识别未知树脂或树脂混合物。 5.3 添加剂会干扰不饱和度测量。使用时应注意确定存在哪些添加剂，以及是否存在因添加剂的存在而导致的任何吸收带，这些吸收带在1050至850 cm范围内与本试验方法中使用的不饱和吸收带重叠或干扰 –1 . 如果出现重叠带，则该方法不适用。 5.4 光滑样品表面产生的干涉条纹可能会导致测量误差。本试验方法要求在样品的模压成型中使用铝箔，以提供足够粗糙的表面，以最小化干涉条纹。

1.1 This test method covers most types of polyethylene, those ethylene plastics consisting of ethylene and α-olefin comonomers longer than propylene, and blends of the above in any ratio. 1.2 The values stated in SI units are to be regarded as the standard. 1.3 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. Specific hazards statements are given in Section 8 . Note 1: There is no known ISO equivalent for this standard. 1.4 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 ====== 5.1 There are three types of olefinic groups present in sufficient concentrations to warrant consideration, one or more of that can normally be found in any polyethylene. The three types are trans-vinylene, R-CH=CH-R ′ , sometimes referred to as trans-internal unsaturation; vinylidene or pendent methylene, RR ′ C-CH2; and vinyl unsaturation, R-CH=CH2, also referred to as terminal unsaturation. 5.2 The type and quantity of these groups can influence the chemical and physical properties of the resin. Information concerning their presence can also be used to characterize or identify unknown resins or blends of resins. 5.3 Additives can interfere with unsaturation measurements. The use is cautioned to determine which additives are present and if there any absorbance bands caused by additive presence that overlap or interfere with unsaturation absorbance bands used in this test method in the range of 1050 to 850 cm –1 . If overlapping bands occur, the method is not applicable. 5.4 Interference fringes resulting from smooth sample surfaces can cause measurement errors. This test method requires the use of aluminum foil in the compression molding of samples to provide an adequately rough surface to minimize interference fringes.