ISO 10119:2020 pdf download – Carbon fibre — Determination of density.
5 Conditioning and test conditions Before testing, test specimens shall be conditioned in a standard test atmosphere as specified in ISO 291. During the test, the test apparatus and specimens shall be maintained at the same conditions as used for conditioning. The preferred conditions are (23 ± 2) °C and (50 ± 10) % relative humidity. 6 Test methods 6.1 Method A: Liquid-displacement method 6.1.1 Principle A specimen is weighed in air and then in a liquid which completely wets out the specimen and which has a known density at least 0,2 g/cm 3 less than that of the specimen. The difference in weight of the specimen in the two media is due to the Archimedean upthrust. 6.1.2 Apparatus and materials 6.1.2.1 Analytical balance, readable to 0,1 mg, with a maximum permissible error of 0,5 mg, and with a range from 0 g to 100 g. 6.1.2.2 Suspension wire, made of stainless steel, of diameter 0,4 mm or less, or a specimen support, made of glass or stainless steel, with perforations so that it can be immersed easily in the immersion liquid (see Figure 1).
6.1.4.2 Determine the exact density of the immersion liquid (6.1.2.7) at the temperature of the test, using the pycnometer (see 6.1.2.3) in accordance with ISO 1675, or the hydrometer (see 6.1.2.3). 6.1.4.3 Weigh the specimen in air to the nearest 0,1 mg (w 1 ). If the specimen is weighed using a suspension wire or specimen support (6.1.2.2), the wire or support shall be tared or weighed and, if weighed, its weight shall be deducted from subsequent weighings of the specimen. 6.1.4.4 Immerse the test specimen in the beaker (6.1.2.4) containing the immersion liquid (6.1.2.7) and remove any air bubbles by agitating the specimen or by pressing it. Weigh the specimen to the nearest 0,1 mg (w 2 ), watching the balance display for a few seconds to make sure that it does not drift as a result of convection currents. The main sources of error are: a) air bubbles adhering to the surfaces of the specimen when weighing in the immersion liquid; b) surface tension effects on the specimen or suspension wire; c) convection currents in the liquid in which the specimen is suspended, to minimize which the temperature of the liquid and of the air in the balance case should be the same. A vacuum pump (6.1.2.5) or ultrasonic device (6.1.2.6) can be used to eliminate air bubbles. In order to minimize the adherence of air bubbles to the test specimen, one of the immersion liquids listed in 6.1.2.7 should be used. If water is used, it is permissible to add a trace (say 1 part in 10 000) of surface-active material such as a detergent to the water.