ASTM D543-95 pdf free.Standard Practices for Evaluating the Resistance of Plastics to Chemical Reagents.
Use three point flexural strain devicescapable of applying known amounts of strain to the testspecimen.The fixtures are to be made of stainless steel withstainless steel tabs at each end capable of affixing the testspecimen to the fixtures in such a way that intimate contact ismaintained between the test specimen and the fixture along theentire length of the test specimen. The clamping system shouldallow for thermal expansion of the material when exposure toelevated temperature is specified.The stainless steel is to be ofType 304 with a surface finish of 64.Fig. 1 provides a drawingof a typical strain fixture along with calculations for determin-ing the radius of curvature required for a specified percentstrain.
Mount the appropriate test specimens,as specified bythe mechanical test being performed, onto strain fixtures that have the radius of curvature necessary to provide the specifiedstrain. Ensure that intimate contact of the specimens andfixtures is maintained along the entire length of the gage areaor specimen area to be tested.Expose the strained test specimens, along with one setof 0.0 % strain (unstrained) specimens, to the reagent beingevaluated for compatibility.The test specimens can be im-mersed in liquid reagents， or alternately, a wet patch methodcan be used.The wet patch method involves applying a cottonpatch (cheesecloth) over the test specimens and saturating thepatch with liquid. For volatile reagents, the liquid should bereapplied daily to provide continuous saturation. Greases canbe wiped directly onto the specimen surface.
Exposure times for chemically exposed and unexposedtest specimens shall be 7 days for room temperature exposureand 3 days for elevated temperature exposure unless otherexposure times are agreed upon between those concerned.Testtemperatures other than room temperature shall be as recom-mended in Practice D 618, unless specified otherwise.Maintain one set of test specimens strained identicallyto the specimens being exposed (including 0.0 %) but with noreagent,to act as a control. If exposure includes elevatedtemperatures, a set of chemically unexposed controls shall beconditioned at the same temperature and times as the exposedspecimen. Control test specimens shall be tested for thespecified mechanical properties at the same time as the exposedtest specimens.After the specified exposure period，determine themechanical properties of the unexposed control and exposedspecimens in accordance with the standard methods for tensile,flexural, or other properties as prescribed in the specificationsfor the materials being tested (see Note 9).Test mechanicalproperties of unexposed and exposed specimens prepared fromthe same sample or lot of material in the same manner, and rununder identical conditions.Test specimens within 24 h afterremoval from chemical agent and removal from strain fixturesunless specified otherwise as agreed upon between thoseconcerned.ASTM D543 pdf download.