ISO 1817 pdf download – Rubber; vulcanized or thermoplastic- Determination of the effect of liquids

ISO 1817 pdf download – Rubber; vulcanized or thermoplastic- Determination of the effect of liquids.
5 Test liquids
The choice of the test liquid shall depend on the purpose of the test.
When information is required on the service behaviour of a vulcanized or thermoplastic rubber in contact with a particular liquid, then this liquid shall. ii possible, be chosen for the test. Commercial liquids are not always constant in composition, and the test shall, whenever practicable, Include a reference material of known characteristics. Any abnormal results due to unexpected variations In the composition of the commercial liquid will thus become apparent. It might then be necessary to set aside a bulk supply of the liquid for a particular series of tests.
Mineral oils and fuels are liable to vary considerably in chemical composition even when supplied at a recognized specification. The aniline point of a mineral oil gives some Indication of Its aromatic content and helps to characterize the action of the oil on rubber, but the aniline point alone is not sufficient to characterize a mineral oil; other things being equal, the lower the aniline point, the more pronounced the action. If a mineral oil Is used as test liquid, the test report shall include the density, refractive Index. viscosity and aniline point or aromatic content of the oil.
Service oils having similar fluid characteristics to the reference liquids (see Clauses A.1 to &3) will not necessarily have the same effect on the material as the reference liquids. Some fuels, particularly gasoline, vary widely in composition and, for some possible constituents, minor variations can have a large influence on the effect on rubber. Complete details of the composition of the fuel used shall therefore be included in the test report.
As commercial liquids do not always have a constant composition, a standard liquid consisting of well- defined chemical compounds or mixtures ofcompounds shall be used as reference liquid forthe purpose of classification of vulcanized or thermoplastic rubbers or quality control. Some suitable liquids are listed In Annex A.
When testing to determine the effect of chemical solutions, the concentration of the solution shall be appropriate to the intended use.
Ensure that the composition of the test liquid does not change significantly during Immersion. The ageing of the test liquid and any interaction with the test pieces shall be taken into consideration. If there are chemically active additives in the liquid, or if there is a significant change in composition by extraction, absorption or reaction with the rubber, either the volume shall be increased or the liquid shall be replaced with fresh liquid at specified intervals.
Report the result as the median value for the three test pieces.
8.8 Testing with liquid on one surface only
This test is applicable to relatively thin sheet materials, for example rubber diaphragms, which are exposed to liquid on one surface only during use.
Measure the nominal thickness of the test piece and then weigh it in air to the nearest milligram (mass mU).
Then place the test piece in the apparatus as indicated in Figure 1. Fill the chamber of the apparatus with the test liquid to a depth of approximately 15mm and Insert the plug (F). Maintain the apparatus at the required temperature for the duration of the test.
At the end ofthe contact period, bringtlw apparatus, lfnecessary. to the standard laboratory temperature.
Remove the liquid and release the test piece. Remove any surplus liquid from the surface of the test piece by wiping with filter paper or a lint-free fabric. Then weigh the test piece to the nearest milligram (mass m1) and measure the thickness at the standard laboratory temperature.
It the test liquid is volatile at room temperature, make the measurement within 2 mm following removal from the liquid.