ASTM D4549-15 (R2021) pdf free download.Standard Classification System and Basis for Specification for Polystyrene and Rubber-Modified Polystyrene Molding and Extrusion Materials (PS).
1.1 This classification system covers polystyrene materials, both crystal and rubber modified, suitable for molding and extrusion.
1.2 This classification system and subsequent line callout (specification) are intended to be a means of calling out plastic materials used in the fabrication of end items or parts. It is not intended for the selection of materials. Material selection can be made by those having expertise in the plastics field after careful consideration of the design and the performance required of the part. the environmenL to which it will be exposed, the fabrication process to be employed, the inherent properties of the material other than those covered by this specilication, and the economics.
1.3 The properties included in this specification are those required to identify the compositions covered. Other requirements necessary to identify particular characteristics important to specialized applications are to he specified using the suffixes as given in Section 5.
1.4 The values stated in SI units are to he regarded as standard. No other units of measurement are included in this standard.
8. Detail Requirements
8.1 Test specimens for the various materials shall conform to the requirements prescribed in Tables PS, A, and B. and suffix requirements as they apply.
8.2 For the purpose of determining conformance, all specified limits for a specification (line callout) based on this classification system are absolute limits, as defined in Practice E29.
8.3 With the absolute method, an observed value or a calculated value is not rounded, but is to be compared directly with the limiting value. Conformance or nonconformance is based on this comparison.
9. Sampling
9.1 Sampling shall be statistically adequate to satisfy the requirements of 13.4.
9.2 A batch or lot shall be construed as a unit of manufacture as prepared for shipment and can consist of a blend of two or more bproduction runs.”
10. Sample Preparation—Injection- or Compressionrs iolding Process
10.1 The test specimens shall be molded by an injection molding process as follows.
10.2 For injection-molded samples, 220 ± 10 °C is the melt temperature and 50 ± 10 °C is the mold temperature.
10.2.1 The injection velocity for molding specimens shall be 200 ± 100 mm/s. Average injection velocity of the flow front through the critical measurement area of the specimen is calculated using the following equation.ASTM D4549 pdf download.