ISO 17278-2013 pdf free download

ISO 17278-2013 pdf free download.Rubber, raw natural — Determination of the gel content of technically specified rubber (TSR)
Cooutchouc naturel brut — Determination de Ia teneur en gel des caoutchoucs spéciflés techniquement (TSR).
6.4 Laboratory oven, gravity convection type, capable of controlling the temperature to ±10 °C.
6.5 Weighing container, i.e. an aluminium box or plate for weighing.
7 CondItions
Laboratory conditions shall be controlled in accordance with ISO 23529.
8 Procedure
8.1 Number of test samples
Two samples shall be taken in accordance with Clause 7 of ISO 2000.1)
8.2 Procedure
8.2.1 Take a test sample from a bale without milling of mass calculated at the ratio of 0,1 g per
30 cm3 of toluene.
NOTE When the volume of a centrifuge tube is 50 cm3, the volume of toluene is 30 cm3 (see 8Z). and the sample weight is 0,1 g.
8.2.2 Cut the test sample into approximately 1 mm3-sized pieces using clean scissors. Weigh the prepared test sample to the nearest 0,1 mg (m0). Place the pieces in a dean centrifuge tube (6.2), which has previously been heated at 100 °C for 1 h and stored in a desiccator.
8.2.3 Add toluene to the tube until It is 60 % full. Cap it and shake by hand for a few seconds. Then, allow it to stand for 16 h to 20 h in dark conditioms without stirring at (25 ± 2) °C.
8.2.4 After this period, shake the tube up and down for 60 s to disperse the jelly-like precipitate on the bottom.
Before placing the tubes in the centrifuge machine, all tubes shall be filled up with fresh toluene, so that the volume of solution is the same in all tubes.
NOTE A centrifuge tube is usually filled up with solution to minimize the dead space created at the top of the tube because of the vacuum-pressured environment during rotation.
Place the tubes in the centrifuge machine and operate the machine at 14 000 r/min for 2 h.
lithe rotating capacity of the centrifuge machine is below 14 000 r/min, operate the machine at 8 000 r/min for 6 h.ISO 17278-2013 pdf free download.