BS 7164 is a series of chemical tests for raw and vulcanized rubber. Natural rubber is soft and sticky. Vulcanized rubber is hard and non-sticky.
BS 7164-27.2 specifies a 1,10-phenanthroline photometric method for the determination of 5 to 1 000 mg/kg of iron in uncompounded natural rubber, uncompounded synthetic rubbers which do not contain chlorine, and in the corresponding uncompounded latices.
BS 7164-27.2 on the determination of iron in uncompounded natural rubber is useful for:
Rubber, also called India rubber, latex, Amazonian rubber, caucho, or caoutchouc, as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, and Indonesia are three of the leading rubber producers. Ashing of the raw rubber or the dried latex solids in a crucible. Extraction of the ash with hydrochloric acid and making up of the solution to standard volume. After adjustment of the pH by the addition of buffer solution, treatment of an aliquot part of the solution with hydroxylammonium chloride to reduce any iron (III) present to iron (II) and 1,10-phenanthroline with which the iron (II) forms an orange-red complex. Photometric measurement of the absorbance of this solution, which is proportional to the concentration of iron.
The test report includes the following particulars in reference to BS 7164-27.2, identification of the test sample, the results and the method of expression used, any unusual features noted during the determination, any operation not included in BS 7164-27.2 or in the International Standards to which reference is made or regarded as optional. Using BS 7164-27.2 you can specify a 1,10-phenanthroline photometric method for the determination of 5 to 1 000 mg/kg of iron in uncompounded natural rubber, uncompounded synthetic rubbers.
ISO 1657:1986