This International Standard specifies methods for the determination of the soap and organic-acid content of
raw styrene-butadiene rubber (SBR). Method A is the titration method using indicator reagent. Method B is the
titration method using an autotitrator or pH-meter.
The methods depend on the extraction of the organic acids and soaps from the rubber by means of a
specified solvent. In practice, therefore, it is convenient to determine both organic-acid and soap contents on
separate portions of the same solvent extract. Since the soaps and organic acids present in the rubber are not
single chemical compounds, the method gives only an approximate value for the soap and organic-acid