4.1 The rubber-filler interaction needed in silica technology for the rubber industry is based on the use of silane-coupling agents that react with the silanol groups on the surface of the silica during the processing step called silanization. Silane-coupling agents are multifunctional molecules able to create molecular bridges between the elastomer or rubber matrix and the silica surface.

1.1 This test method is used to determine the number of silanol groups on the surface of silica by titration according to a method as developed by Sears. This test method is suitable for characterizing rubber-grade silicas.

1.2 Units—The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.