ISO 14852:2018 pdf free

ISO 14852:2018 pdf free.Determination of the ultimate aerobic biodegradability of plastic materials in an aqueous medium
The test material shall be of known mass and contain sufficient carbon to yield CO2 in a quantity that can be adequately measured by the analytical system used. Calculate the TOC from the chemical formula or determine it by a suitable analytical technique (e.g. elemental analysis or measurement in accordance with ISO 8245) and calculate the ThCO2. Use a concentration of a test material such that the TOC content is at least 30 mg/l preferably 100 mg/l. The maximum amount of test material is limited by the oxygen supply to the test system and the test medium used. When using higher amount of test material, the optimized test medium [6.2.2] should be used and, in any case the test-material concentration shall be such that the TOC does not exceed about 2 000 mg/l, i.e. a C:N ratio of about 40:1.
If higher concentrations are to be tested, increase the nitrogen amount in the test medium.
NOTE Lower amount of test materials, corresponding to a TOC content between 20 mg/l and 40 mg/l, have been tested and found suitable.
The test material should preferably be used in powder form, but it may also be introduced as films,pieces, fragments or shaped articles. The form and shape of the test material may influence its biodegradation. Similar shapes should preferably be used if different kinds of plastic material are to be compared. If the test material is used in the form of a powder, particles of known, narrow size distribution should be used. A particle-size distribution with the maximum at 250 μm diameter is recommended. Also, the size of the test equipment used may depend on the form of the test material.
It should be ascertained that no substantial mechanical aberrations occur due to the test conditions,for example due to the type of stirring mechanism used. Processing of the test material (e.g. the use of powder in the case of composites) should not influence significantly the degradation behaviour of the material. Optionally, record the hydrogen, oxygen, nitrogen, phosphorus and sulfur contents and the molecular mass of a polymeric test material, using for example liquid exclusion chromatography (see, for example, ASTM D 3536-91[72] or any other applicable standard method).
For details on how to handle poorly water-soluble compounds, see ISO 10634.ISO 14852 pdf download.