BS ISO 9924-1:2016 pdf free

BS ISO 9924-1:2016 pdf free.Rubber and rubber products – Determination of the composition of vulcanizates and uncured compounds by thermogravimetry
Provided that nitrogen having a low enough concentration of oxygen is used, that purging is carried out for a time greater than the purge time determined in 6.1, that there are no leaks in the ? apparatus, and that the oven design and gas flow rate ensure that all carbon dioxide is swept out from the sample chamber, there should be no problem in distinguishing between, and measuring separately, black and whiting (calcium carbonate). To check the operation of the thermogravimetric analyser, carry out the following procedure:
Grind together equal (to within 1 %) masses of analytical-grade calcium carbonate and the purest grade of carbon black available.
Into the thermogravimetric analyser balance pan, introduce a mass of the carbon black/calcium carbonate mixture (see 6.2.3) as specified in the manufacturer’s instructions.
Close the apparatus and purge with a stream of nitrogen at a constant and predetermined flow rate which is in accordance with the manufacturer’s instructions. Continue purging with nitrogen for a time which is greater than the purge time, tp (see 6.1).
Maintain the oven temperature at 800 °C until the mass indicated on the mass/temperature (or mass/time) plot is constant, then lower the temperature to 300 °C.
Switch from the stream of nitrogen to a stream of air or oxygen, or partly replace the nitrogen by air or oxygen. Adjust the total flow rate of the gas flowing through the apparatus so that there is no discernible change in the apparent mass of the sample. This procedure corrects for changes in buoyancy of the balance pan and test portion in gases of different density.
Raise the oven temperature to 800°C as rapidly as possible and maintain it at 800°C for 15 min or until the mass indicated on the plot is constant.
Switch off the oven heater and replace the stream of air or oxygen by a stream of pure nitrogen.Switch off the recorder and empty the ash residue from the balance pan. The apparatus is now ready for the next test portion. BS ISO 9924-1 pdf free.