ISO 247-1:2018 pdf download.Rubber – Determination of ash Part 1 : Combustion method.
ISO 247-1 specifies three methods for the determination of ash from raw rubbers, compounded rubbers and vulcanizates. The methods are applicable to raw, compounded or vulcanized rubbers of’ the M, N, 0, R and tJ families described in ISO 1629, except that:
— Method A is not used for the determination of ash from compounded or vulcanized rubbers containing chlorine, bromine or iodine;
Method B is used for compounded or VulcaniZe(l rubbers containing chlorine, bronune or iodine. It shall not be used for uncompounded rubbers;
— Method C is intended to be used for the determination of ash from raw, compounded or vulcanized rubber not containing cli Ion ne, bromine or Kid 1W by wrapping the test port ion in ash less filter paper;
— Lit hium and fluorine compou ink might react with silica crucibles to form volatile compou iids, giving low ash results. Platinum crucibles shall therel’ore be used [or ashing fluorine—containing and lithium—polymerized rubbers.
ISO 247-1 clues not cover the interpretation of the ash results as to the inorganic chemical content of’ a compound or vulcanizate. This is the responsibility of the analyst, who has to be aware of’ the behaviour of rubber acid itives at elevated temneratures.
ISO 247-1 specifies three methods for the determination of ash from raw rubbers, compounded rubbers and vulcanizates. The methods are applicable to raw, compounded or vulcanized rubbers of’ the M, N, 0, R and tJ families described in ISO 1629, except that:
— Method A is not used for the determination of ash from compounded or vulcanized rubbers containing chlorine, bromine or iodine;
Method B is used for compounded or VulcaniZe(l rubbers containing chlorine, bronune or iodine. It shall not be used for uncompounded rubbers;
— Method C is intended to be used for the determination of ash from raw, compounded or vulcanized rubber not containing cli Ion ne, bromine or Kid 1W by wrapping the test port ion in ash less filter paper;
— Lit hium and fluorine compou ink might react with silica crucibles to form volatile compou iids, giving low ash results. Platinum crucibles shall therel’ore be used [or ashing fluorine—containing and lithium—polymerized rubbers.
ISO 247-1 clues not cover the interpretation of the ash results as to the inorganic chemical content of’ a compound or vulcanizate. This is the responsibility of the analyst, who has to be aware of’ the behaviour of rubber acid itives at elevated temneratures.
When the rul)ber has decomposed to a chart-ed mass, gradually increase the heat from the but-ncr until the volatile decomposition products have been sul)stantially expelled and a dry carbonaceous residue remains. Transfer the crucible and its contents to the muffle furnace, maintained at 550 °C ± 25 °C (for compounds and vulcanizates, a temperature of 950 °C ± 25 °C may be used), leaving the door of the furnace slightly open for 1 mm to provide sufficient air to oxidize the carbon.
Continue heating until the carbon is completely oxidized and a clean ash is obtained. Remove the crucible and its contents from the furnace, allow to cool to aml)ient temperature in the desiccator and weigh to the nearest 0,1 mg. Then heat the crucible and its contents again for about 30 mm in the muffle furnace, maintained at 550 °C ± 25°C (for compounds and vulcanizates, a temperature of 950 °C ± 25 °C may be used), allow to cool to ambient temperature in the desiccator and re-weigh to the nearest 0,1 mg. This mass shall not diftet- from the previous mass by more than 1 mg in the case of raw rubbers or by more than 1 % relative to the amount of ash for compounds and vulcanizates. If this requirement is not fulfilled, repeat the heating, cooling and weighing procedure until the difference between two successive weighing meets this requirement.ISO-247-1-2018