ISO 247-2-2018 pdf free.Rubber — Determination of ash — Thermogravimetric analysis (TGA).
A weighed test portion is heated in an atmosphere of nitrogen.After complete decomposition of thepolymer, the atmosphere is switched from nitrogen to oxygen or air and the test portion is furtherheated until all the carbonaceous matter has been burnt off and a constant mass is reached.The mass ofthe residue represents the ash.
Thermogravimetric analyser, comprising the following elements:Thermo-balance;Heating furnace;Temperature programmer;Gas flow controller, for controlling the purge gas to the balance and furnace, and keeping a constant flow rate.
Sample pan, platinum pan or alumina ceramic pan.
Analytical balance, capable of weighing to the nearest 0,1 mg.
For raw natural rubber,test samples shall be cut from the homogenized piece prepared inaccordance with lSO 1795. For raw synthetic rubber, test samples shall be cut from the dried rubberobtained after carrying out the determination of volatile-matter content in accordance with the hot-millmethod of ISo 248-1.Take a test portion of about 2 g to 5 g from the homogenized sample and cut into pieces by hand.
Test samples of rubber compounds shall be sheeted on a mill and cut into pieces by hand.
Test samples of vulcanizates shall be sheeted or crumbed on a mill or comminuted by hand.
Care shall be taken to ensure that test samples of rubber compounds and vulcanizates arerepresentative of the sample.
Calibrate the thermogravimetric analyser (see 6.1) according to the manufacturer’s instructions.Temperature and mass calibration should be performed.
To ensure consistent results, the thermogravimetric analyser shall be calibrated periodically. It isrecommended to perform mass calibration once a month.
Switch on and stabilize the instrument, set the temperature of furnace to 30 °C.9.1.2 Place an empty sample pan on the platform and tare the sample pan.
Take about 10 mg to 20 mg from the test portion of raw rubber (see Z.1) and weigh to the nearest0,1 mg. Place it in the sample pan. Position the sample pan on the sample platform and load the samplepan onto the thermo-balance.
Set the flow rate according to the manufacturer’s instructions. Raise the temperature to 500 C ata rate of 20 °C/min or 30 °C/min under an atmosphere of nitrogen.Maintain at this temperature for 1 min.Switch from the stream of nitrogen to a stream of oxygen or air. Raise the temperature to 550 0c.Maintain the temperature at 550 °C for 5 min or until the mass is constant.Calculate the ash using the apparatus micro-processor.ISO 247 pdf download.