Method for the definition of edema
establishes a method for quantitative determination of cellulose swelling
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Laboratory scales of general purpose with the maximum weighing limit of 500 g and an error of no more than 0.02 g in accordance with GOST 24104. stopwatch;
thermometer type B with a scale division price of 0.1 and 1.0 * C in accordance with GOST 28498;
laboratory filter paper in accordance with GOST 12026;
sodium hydroxide according to GOST 4328. member,
(17.50 ± 0.15)% aqueous solution;
/ - the rod; 2 - pint: 3 - cover: 4 - upper ring: 5 ■ lower ring: 6 - cylinder
water distilled according to GOST 6709.
(Shaded edition, Amendments No. 1, 2).
And official mania Reprintsa vepredenshena
© Publishing house of standards. 1975 £> Publishing house of standards. 1998 Reissue with Changes
3. PREPARATION FOR TEST
3.1. One cellulose sample is cut from each sheet of cellulose selected for testing.
From the sheets of cellulose, treated with surface-active substances (surfactants), samples are cut between the bands of surfactant sheets applied to the surface, i.e. without surfactants.
Samples cut at a distance of at least 10 cm from the edge of the sheet. The edges of the circles should be even.
3.2. The cut out samples of cellulose are mixed and then conditioned for 4 hours at relative air humidity (50 ± 2)% and temperature (23 ± 1) "C according to GOST 13523.
After the conditioning time has expired, the cellulose samples are placed in a tightly closed hermetically sealed can, where they are removed immediately before the swelling is determined.
(Changed edition, Change No. 2).
4.1. The rod with two plates is weighed up to the second decimal point and threaded with 10 samples of conditioned cellulose. Then, the rod with the plates and cellulose samples is again weighed, and the weight of the cellulose samples to be tested is determined by the difference.
(Changed edition, Amendments No. 1, 2).
4.2. The stem with cellulose and plates is placed in a glass cylinder filled with 70 cm * sodium hydroxide solution at a temperature of (20 ± 0.2) ° C and fixed with a clamp in the cover of the device so that the bottom plate is about 5 mm from the bottom cylinder. The cylinder is placed in a water thermostat to maintain the temperature of sodium hydroxide throughout the swelling process (20 ± 0.2) 'C.
The duration of the swelling process is 5 min. Time is counted according to the stopwatch from the moment the cellulose rod is lowered into the sodium hydroxide solution.
When analyzing cold sulfate cord pulp, 80 cm of sodium hydroxide solution is poured into the cylinder.
4.3. After 5 min. without removing the device from the thermostat, the rod with cellulose is lifted and secured in the cylinder cover. that cellulose was higher than sodium hydroxide. In this position, allow excess sodium hydroxide to drain from the cellulose for 5 minutes. At the same time, the temperature is also maintained (20 ± 0.2) * C.
Then the cellulose rod is removed from the cylinder and the outer walls of the plates and the rod above the upper plate are carefully dried with filter paper.
It is also necessary to remove the rest of the solution.sodium hydroxide from the holes in the plates that serve to facilitate the access of sodium hydroxide to cellulose. Avoid contact of the filter paper with swollen cellulose specimens and do not move them along the rod.
After that, the rod with cellulose and plates are weighed.
4.2. 4.3. (Revised Edition, Rev. No. I, 2).
5.1. Swelling (L) in percent is calculated by the formula
where t is the mass of the rod with two plates;
/ i, is the mass of the rod with plates and samples of cellulose before swelling, g;
/ and, - the mass of the rod with plates and samples of cellulose after swelling, g.
For the test result, the arithmetic average of the results of two parallel determinations, rounded to 10%, is taken.
The discrepancy between parallel definitions should not exceed 20%.
6. The limitation of validity is lifted by the Resolution of the State Standard dated August 20, 1991 No. 1369
7. REVISION (August 1998) with Amendments No. 1, 2, approved in March 1986, August 1991 (IUS 6—86, 11-91)
Editor TS Sheko. Technical editor N. Prutkov. Proofreader B.C. Scooping Computer Layout LL Circular
Above. lee. Si 021007 from 10.08.95. Slano to the set 08/31/98. Signed in the Pecha. 09/22/98. Out pecs I. 0.47. Uch. jad l 0.33.
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