ISO 6964:2019

ISO 6964:2019 pdf free.Polyolefin pipes and fittings -Determination of carbon black content by calcination and pyrolysis – Test method.
It is possible to determine the carbon black content of polyolefin compositions by one of the following three methods:
a) Pyrolysis of the sample at (550 ± 50) °C in a stream of nitrogen for 45 mm followed by calcination at (900 ± 25) °C, by using an electrical tube furnace (Method A).
b) Pyrolysis of the sample in a quartz crystal crucible with lid, by using a muffle furnace. According to the type of muffle furnace used there are two different procedures:
1) Conventional muffle furnace (Method Bi): pyrolysis from (325 ± 25) °C to (550 ± 25) °C at
15 °C/min and at (550 ± 25) °C for (10 ± 05) mm followed by calcination at (900 ± 25) °C.
2) Microwave muffle furnace (Method B2): pyrolysis at (520 ± 25) °C for (10 ± 0,5) mm followed by calcination at (900 ± 25) °C. c) Pyrolysis of the sample at a constant rate in a thermogravimetric analyzer (TGA) under inert atmosphere at 800 °C followed by calcination under oxidizing atmosphere at 900 °C (Method C). NOTE 1 Carbon black is decomposed from 500 °C In air or oxygen. Therefore, the loss observed between 500 °C and 700 °C in air or oxygen corresponds to the overall decomposition of the carbon black. NOTE 2 If the composition contains, in addition to the carbon black, additives likely to decompose at 900 °C, for example ingredients such as calcium carbonate, the calculation can lead to an over-estimation of the carbon black content. lithe ash yield is more than I %, further investigation can he required. Calculate the carbon black content from the difference in mass before and after calcination and pyrolysis.
4 Method A: Electrical tube furnace
4.1 Reagents
4.1.1 Dry nitrogen, having an oxygen content less than 20 ppm, under pressure in a steel cylinder provided with a pressure-reducing valve and flow meter.
NOTE If required, the nitrogen can be purified by bubbling the gas through a pyrogallol solution or by passing it over heated copper tinsel, foil, wire or turnings or by passing it through a gas purifier prior to passing into the furnace.
4.2 Apparatus
4.2.1 Silica combustion sample boat, with a sleeve or 50 mm to 60 mm long.
4.2.2 ElectrIc tube furnace, fitted with a device to allow the sample boat to be inserted and withdrawn. The tube is fitted with nozzles to admit the nitrogen and to evacuate the fumes. A diaphragm closed by means of a glass-wool bung placed behind the entry nozzle ensures that the nitrogen stream is distributed uniformly.
The minimum length of the electric tube furnace should be  3 times the length of the sample boat, and the minimum length of the quartz tube should be  7 times the length of the sample boat.
4.2.3 Desiccator, capable of holding the silica sample boat (4.2.1).
4.2.4 Balance, with an accuracy of± 0,1 mg.
4.2.5 Timer, with an accuracy of ± 1 s.
4.3 Procedure
4.3.1 Test conditions Determination of mass shall be carried out in a room at standard temperature (23 ± 2) °C.
4.3.2 Sampling Test specimen may be in the form of pellet or finished product. In the last case, the specimen shall be reduced to small fragments.
4.3.3 ConditIoning The test sample shall be conditioned for 24 h at (23 ± 2) °C before preparation.
4.3.4 Silica sample boat preparation for the test
Take the silica sample boat which shall be clean and weighed, and proceed as follows:
Place the silica sample boat in the electric tube furnace and adjust the temperature to (900 ± 25) °C. Once this temperature is reached, leave to calcination for approximately 1 h. Then, dry the silica sample boat in the desiccator at room temperature and weigh. Place again the silica sample boat into the desiccator for 30 mm and weigh again. This operation shall be repeated until constant mass, i.e. until two consecutive weighing do not differ by more than 0,5 mg. This weighing is recorded as m.
ISO 6964 pdf download.

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