1.1 This part of ISO 248 specifies two methods for the determination of volatile-matter content in raw rubbers by using a hot mill or an oven. 1.2 The methods are applicable to the determination of the volatile-matter content in the “R” group of rubbers listed in ISO 1629. These are rubbers having an unsaturated carbon chain, for example natural rubber and synthetic rubbers derived at least partly from diolefins. The methods can also be applicable to other raw rubbers, but in these cases it is necessary to demonstrate that the change in mass is due solely to loss of actual volatile matter and not to rubber degradation. 1.3 The hot-mill method is not applicable to natural rubber, to synthetic rubbers which are too difficult to handle on a hot mill or to synthetic rubbers in powder or chip form. 1.4 The test methods do not necessarily give identical results. Therefore, in cases of dispute, the oven method, procedure A, is the reference method. NOTE The applicability of each test method to various types of rubber is summarized in Annex A.