ISO 18852:2005 pdf download.Rubber compounding ingredients —Determination of multipoint nitrogen surface area (NSA) and statistical thickness surface area (STSA).
6.8 Determine the intern volume of the calibration-volume reservoir (4.8) below the valve or stopcock by the difference in mass when empty and then wtien filled corn pletety with distilled water (5.2), Measure the water temperature and use the correct water density to obtawi the exact volume of water contained. It may be necessary to Immerse the device In boiling water to ensure complete filling and degassing. Repeat the procedure until the calibration volume is known to better than 0.1 %. Empty the calibration volume and thoroughly dry It overnight in the vacuum oven at 70 °C ± 5°C.
6.9 Connect the calibration-volume reservoir to a sample port of the gas adsorption apparatus, open the valve or stopcock, and evacuate the reservoir to below 2,7 Pa (20 pmHg). Continue evacuation for one more hour. Close off the path to the vacuum source and note whether any nse In pressure occurs. The pressure shall remain below 2.7 Pa (20 pmHg). with a rate of increase of less than 0,04 Pa (0.3 pml’lg) per minute. When this has been achieved, close the valve or stopcock to maintain the vacuum within the calibrationvolume reservoir.
6.10 Leave the closed-off, evacuated calibration-volume reservoir in place. Raise a Dewar flask (or other insulating container) around it, and pack wet, crushed ice firmly c the Dewar flask. Place an insulating cover on the Ice. Start an analysis with target relative pressures of 0,025; 0.05; 0.10; 0.15: 0,20 and 0,25/j. Use a 1 g mass and a p0 of 101,325 kPa (760 mmHg) for the calculations.
6.9 Connect the calibration-volume reservoir to a sample port of the gas adsorption apparatus, open the valve or stopcock, and evacuate the reservoir to below 2,7 Pa (20 pmHg). Continue evacuation for one more hour. Close off the path to the vacuum source and note whether any nse In pressure occurs. The pressure shall remain below 2.7 Pa (20 pmHg). with a rate of increase of less than 0,04 Pa (0.3 pml’lg) per minute. When this has been achieved, close the valve or stopcock to maintain the vacuum within the calibrationvolume reservoir.
6.10 Leave the closed-off, evacuated calibration-volume reservoir in place. Raise a Dewar flask (or other insulating container) around it, and pack wet, crushed ice firmly c the Dewar flask. Place an insulating cover on the Ice. Start an analysis with target relative pressures of 0,025; 0.05; 0.10; 0.15: 0,20 and 0,25/j. Use a 1 g mass and a p0 of 101,325 kPa (760 mmHg) for the calculations.
