ASTM D5870-16
用于计算塑料性能保留指数的标准实施规程
Standard Practice for Calculating Property Retention Index of Plastics
- 标准号
- ASTM D5870-16
- 发布
- 2016年
- 发布单位
- 美国材料与试验协会
- 替代标准
- ASTM D5870-22
- 当前最新
- ASTM D5870-22
- 引用标准
- ASTM D1435 ASTM D1499 ASTM D1898 ASTM D2565 ASTM D3045 ASTM D4329 ASTM D4364 ASTM D4459 ASTM D4674 ASTM D543 ASTM D618 ASTM D6360 ASTM D883 ASTM G113 ISO 11248 ISO 291 ISO 4892 ISO 877
- 适用范围
4.1 The property retention index (PRI) determined by this practice is intended primarily to provide relative durability performance information on materials for design engineers. It is up to the user to ensure that appropriate sampling procedures are used for the selection of specimens to be exposed so that the PRI data obtained is actually representative of the material being evaluated.
4.2 The PRI obtained depends on the material being tested, property being evaluated, and exposure condition used. A PRI obtained for one property will probably not be the same as the PRI for a different property of the same material, even if the same exposure test is used.
4.3 Plastics exposed to a combination of environmental and thermal treatments may undergo a change in functional performance. Any laboratory-accelerated aging procedure, especially those that use only a single stress, may not realistically indicate the changes a plastic may undergo in actual use conditions. This practice provides a means for expressing the changes in properties as a function of time exposed in a wide variety of tests. The PRI data obtained is best used for comparing the performance of materials subjected to the same exposure test simultaneously.
4.3.1 Both laboratory-accelerated and outdoor exposure testing can be highly variable, and the PRI data will be influenced by this variability. For example, PRI data from outdoor exposures can vary depending on the exposure location and the time of year when the exposure is conducted. Variability in laboratory-accelerated exposure tests can result in large differences in PRI data from two laboratories running supposedly identical tests. PRI data obtained from exposure to laboratory-accelerated tests cannot be used to predict the PRI for exposure to natural weathering or actual use conditions unless there is a sufficient amount of data from both types of exposure to allow valid statistical comparisons.
4.4 A number of different exposure techniques can be used to provide information on the effects of environmental stresses such as light, heat, and water on plastics (see Practices D1435, D1499, D2565, D4329, D4364, and D4459; Test Method D4674; and ISO 877 and ISO 4892). When it is desirable to evaluate the effects of heat alone, exposures should be conducted in accordance with Practice D3045. When it is desirable to evaluate the effects of chemical exposures, the exposures should be conducted in accordance with Test Method D543.
4.5 There are a number of factors influencing the physical properties and the retention of these properties after exposure. In addition to a complete description of the exposure test conditions used, the following information shall be included in any report referencing this practice: (1) complete description of the material tested, including the type, source, manufacturer's code number, form, and previous history; (熔融指数简介
熔融指数是按照GB/T3682-2000、ASTM D1238-98标准，并参看JB/T5456、ISO1133等类似标准设计制造的用于测定热塑性塑料熔体体积流动速率（MFR）的仪器，测定熔体质量流动速率采用自动取样，天平称量的方式；然后根据公式计算出体积流动速率。测定的最终结果显示在仪器的液晶屏上，并由微形打印机输出。...