EN ISO 3451-5:2002 pdf free.Plastics – Determination of ash- Part 5: Poly(vinyI chloride).
5 Apparatus
Apparatus as specified in ISO 3451-1. and in particular
5.1 Crucible of silica, platinum or porcelain with lid, diameter of upper part 45 mm to 75 mm, height equal to the diameter. The size shall be such that the crucible is not more than hah.filled by the test portion.
5.2 Bunsen burner, with silica triangle and tripod, or other suilable heating device.
5.3 Muffle furnace or microwave furnace, capable of being controlled thermostatically at 950 °C + 50°C.
5.4 Pipettes, of appropriate capacity ( methods B and C only).
WARNING — In 7.3.4 and 7.4.3, it is required to use a pipette for the addition of concentrated sulfuric acid. The acid must be introduced into the pipette using a suitable device (e.g. a rubber-bulb pipette filler) and must never be sucked up by mouth.
5.5 Desiccator, containing an effective drying agent that does not react chemically with the ash components
NOT[ In son’e cases. t-,e affinity of ash r water can be greater than that of dry ng agents comironly used.
5.6 Analytical balance, aaurate to 0.1 mg
5.7 Weighing bottics
6 Safety precautions
6.1 Always wear safety glasses when working in the laboratory.
6.2 Exercise all normal safety precautions when working with an open flame or at high temperatures. Use insulated gloves and long crucible tongs when putting samples in the muffle Furnace or taking them out of it
6.3 Carry out the heating of the sample in a fume cupboard. and for calciriation use an appropriatofy vented muffle furnace
6.4 Read careful’y and follow strictly the instrUctions in the warnings at the beginning of the text and in clause 4 and subclauses 5.4 and 7.4 3
7 Procedure
7.1 Test portion
The recommended test portion size is given in Table 1.
7.2.1 Heat the clean crucible and lid (5.1) in the muffle furnace (5.3) at 950 ‘C 50 C for 10 mm and cool in the desiccator (5.5) to room temperature. Weigh the crucible with lid to the nearest 0,1 mg.
7.22 Introduce into the crucible a suitable quantity of sample (see Table 1) (hnished product samples should preferably be cut into small pieces). Weigh the crucible with lid and test portion to the nearest 0.1 mg and cakuIate the mass of the test portion (rr).
7.2.3 Heat the crucible directly on the heating device (5 2) so that the test portion burns slowly and kiss of ash is avoided. Continue this operation until no more smoke is evolved.
In the event of violent burning, the test portion may be added in successive poctns.
7.2.4 Partially close the crucible with the lid so that the volatile matter evolved does not carry away partIes of ash.
Place the crucible at the entrance of the muffle furnace maintained at 950 °C ± 50°C (the temperature in the
entrance zone is about 300 °C to 400 ‘C). then advance the crucible slowty into the furnace. Calcinate for 30 mm at
950°C ± 50°C
It is recommended that the design of the lid be such that, when placed on the crucible, the lid fits well but does not close the crucible completely.
7.2.5 Remove the crucible with led from the furnace, place it in the desiccator, allow to 0001 to room temperature and weigh to the nearest 0,1 mg (in,).
7,2.6 Calcinate again, under the same conditions, until constant mass is reached: i e. until the results of to consecutive weighinc, do not differ by more than 0,5 mg. The total duration of heating in the furnace shall however not exceed 3 h. If constant mass is not attained after this time. the mass after 3 h shall be used for calculating the test results.
7.3 Method B (determination of sulfated ash)
7.3.1 Proceed as detailed in 7.2.1
7.3.2 Proceed as detailed in 7.2.2.
7.3.3 Proceed as detailed in 7.2.3.
7.3.4 After allowing the crucible and contents to cool. add concentrated sulfuric acid (4 1) dropwise by means of a pipette (54) of suitable capacity until the residue is soaked completely Heat carefully on a suitable heating device (5 2) until the evolution of smoke ceases. taking care to avoid spattering of the contents of the crucible
7.3.5 If. after allowing the crucible to cool. carbon is still evident, add I to 5 drops of sulfuric acid and reheat until evolution of white fumes has ceased.EN ISO 3451-5 pdf download.