Hydrolytic stability test methods

In many commercial brochures, chemical resistance is indicated as excellent, good, fair, or poor. Although the test method is usually outlined, wide interpretation is possible. Immersion tests are usually described in this manner. Hydrolytic stability is tested by salt-spray cycling or autoclave cycling. 

Hydrolytic stability. The test method required treating the fluids with 0.1% water and maintaining the fluid at 77°C for up to 200 h. Samples were withdrawn at 20-h intervals, and the flash points were measured by the closed cup method. A decrease in flash point was interpreted as being indicative of hydrolytic breakdown to form low molecular weight products. The PAO showed no decrease in flash point under any of the test conditions. 

ASTM D 3137-81 (1987) Standard Test Method for Rubber Property — Hydrolytic Stability, 3 pp (DOD Adopted) (FSC 9320) (MR) (Comm D-11)... 

Polyesters do vary in their resistance to hydrolysis and this variability is reflected in the hydrolytic stability of the polyurethanes. Sometimes it is possible to perform hydrolysis tests on the polyols which give good correlation with the stability of final polyurethane. One such method is the hydrolysis of the polyester by sodium hydroxide solution at 100°C. 

During the Second World War a number of triorganolead-substituted sulfonamides, phthalimides, and a sulfimide were prepared and tested as potential sternutators 111, 112,113). The methods of preparation included the reaction of triethyl- or tripropyllead chloride with the sodium derivative of a sulfonamide, and the reaction between triethyl- or tripropyllead hydroxide and a sulfonamide. Both reactions were generally carried out in ethanol, and the product was precipitated by the addition of water. This demonstrates the hydrolytic stability of these compounds. The phthalimides and the sulfimide were prepared from the organolead hydroxides. They show the same high hydrol)rtic stability. 

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