ASTM D2225 Test Methods for Silicone Fluids Used for Electrical Insulation
CHEMICAL METHODS
14. Neutralization Number
14.1 Significance - In the inspection of unused silicone fluids, the neutralization number is of importance as a quality index of purity. Properly refined silicone fluids are free from mineral acids and alkalies.
14.1.1 Since final oxidation products of silicone fluids are not acidic, small changes in the neutralization number of used silicone fluids may indicate the solution of basic or acidic materials from the various solid materials in contact with the silicone or the deterioration of such soluble materials to form basic or acidic materials.
14.2 Procedure - Determine the neutralization number in accordance with Test Method D974.
15. Water Content
15.1 Significance - Under high humidity conditions, polydimethylsiloxane fluids can absorb moisture up to about 250 ppm by weight at 25°C. High levels of water content will significantly lower the resistivity and dielectric breakdown voltage of the fluid.
15.2 Procedure - Determine water content in accordance with Test Method D1533.
