BS ISO 28641:2018 pdf free

BS ISO 28641:2018 pdf free.Rubber compounding ingredients – Organic chemicals – General test methods
a) Put the sample in the cylinder, avoiding the inclusion of air bubbles. Maintain the cylinder in the constant-temperature water bath. Stir the sample. Monitor the temperature of the sample with the thermometer, immersing it to the designated mark.
b) Condition the hydrometer at 20 °C±0,5 °C. When the temperature of the sample has reached 20 °C±0,5 °C, slowly put the conditioned hydrometer into the sample and allow it to come to rest.Then push the hydrometer into the sample by about two-scale divisions and release it.
c) When the hydrometer has stopped moving and is not in contact with the cylinder wall, read the scale to half the smallest graduation interval.
For a translucent sample, read the scale at the point corresponding to the plane of intersection of the sample surface and the stem. Do this by gradually raising the eyes from a level a little below the sample surface and reading the scale when the elliptical sample surface becomes straight.For an opaque sample, read the scale at the upper edge of the meniscus of the sample surface and calculate the equivalent lower-edge value by applying a correction in accordance with Clause 4 of ISO 649-2:1981.
a) Dry the clean weighing bottle and the stopper in the drying oven. Allow them to cool to room temperature in the desiccator. Weigh the weighing bottle with the stopper to the nearest 0,1 mg.Record the mass (mo).
b) Take a test portion of between 3 g and 5 g from the sample and put it into the weighing bottle.Insert the stopper and weigh the bottle to the nearest 0,1 mg. Record the mass (m1).
c) Place the weighing bottle in the drying oven. Remove the stopper and place it near the bottle. Heat under the conditions specified in Table 1 (for accelerators and vulcanizing agents) or Table 2 (for antidegradants). After heating, transfer the weighing bottle and stopper to the desiccator and leave them to reach equilibrium at room temperature. Weigh the weighing bottle and stopper to the nearest 0,1 mg. Record the mass (m2).
d) Repeat procedure a) to c) to give a second result.BS ISO 28641 pdf free download.