This document specifies four methods for the quantitative determination of the material extractable from raw rubbers, both natural and synthetic; two of the methods are also applicable to the unvulcanized and vulcanized rubber compounds.
Method A measures the mass of the solvent extract, after evaporation of the solvent, relative to the mass of the original test portion.
Method B measures the difference in the mass of the test portion before and after extraction.
Method C, which is for raw rubbers only, measures the difference in the mass of the test portion before and after extraction using boiling solvent.
Method D, which is for raw rubbers only, measures the difference in the mass of the test portion before and after extraction relative to the mass of the original test portion.
NOTE 1 Depending on the test method used, the conditioning of the test portion and the solvent used, the test result is not necessarily the same.
NOTE 2 Method C generally gives results which are lower than those obtained with methods A and B due to an equilibrium which is set up, particularly if large test portions are used, depending on the content and the nature of the extractable matter. Method C is, however, a quicker method than method A or method B.
NOTE 3 Methods C and D are not suitable if the test portion disintegrates during the extraction.
NOTE 4 Method D is normally used for production controls.
Recommendations as to the solvent most appropriate for each type of rubber are given in Annex A.
