BS ISO 7270-1:2020 pdf free.Rubber一Analysis by pyrolytic gas-chromatographic methods.
Accurate comparison of the pyrogram of an unknown polymer with the reference is only possible under the same conditions. Extraction of test samples is recommended to remove additives which may interfere with the chromatographic separation. For oil-extended materials, extraction of the extender oil is essential otherwise this oil may cause serious interference in the pyrogram. Carry out the extraction following the general principles of either method A or method B in ISO 1407:2011. The chosen solvent shall not affect the polymer and shall remove as much of the additives as possible. After extraction, dry the test sample, as residual solvent may cause interference with the pyrolysis products (see 9.4).  Take a test portion of mass appropriate to the apparatus used. Generally, this will be between 0,1 mg to 5 mg. For good reproducibility, the size of the test portion should be as small as practicable.Place the test portion in the pyrolysis device and pyrolyse. An appropriate pyrolysis temperature is 400 °C to 800 °C for a micro-furnace or Curie-point pyrolyser, and 800 °C to 1 200 °C for a platinum- filament pyrolyser. Record the pyrogram for comparison with the pyrogram of a known polymer or polymer blend obtained under the same conditions.Some polymers do not yield characteristic hydrocarbons, and careful inspection of the pyrogram is required. Supplementary tests, such as those for halogen and nitrogen, may be an aid to more definite identification.The characteristic hydrocarbons in the unknown polymer are identified by comparison of retention times for a known blend of polymer, or by direct injection of the pure hydrocarbon into the chromatograph. Results may be tabulated for ready reference.The analyst should be aware of additives which may not be extractable and which may or may not affect the chromatographic pattern.The test report shall contain the following information: a) all details necessary for full identification of the sample analysed; b) the type of pyrolysis device used;  c) the pyrolysis temperature;  d) the gas-chromatographic conditions used; e) the data-handling equipment used; f) the polymer or polymer blend found in the sample.BS ISO 7270-1 pdf download.