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ASTM D2876-00(R2020) pdf free download

ASTM D2876-00(R2020) pdf free download.Standard Test Method for Water-Soluble Matter of Vegetable-Tanned Leather
1. Scope
1.1 This test method covers the determination of the water- soluble materials in all types ofvegetable-tanned leathers. This test method does not apply to wet blue. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety and health practices and determine the applica- bility ofregulatory limitations prior to use.This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility ofthe user ofthis standard to establish appropriate safety, health, and environ- mental practices and determine the applicability ofregulatory limitations prior to use. 1.4 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
4. Significance and Use
4.1 The test method is useful for determining the water- soluble materials in vegetable-tanned leathers. 4.2 The water-soluble matter includes the soluble nontan- ning components of the tanning materials used, sugars and materials of a similar nature, and inorganic compounds such as Epsom salts, Glauber’s salts, borax, and other soluble salts added during curing and tannery processing.
5. Apparatus
5.1 Crystallizing Dish, borosilicate glass, 50 mm tall, 70 mm in outside diameter, and weighing between 30 and 39 g. 5.2 Extractor, Reed-Churchill Type 3 —The extraction tube shall have an internal diameter of 45 6 2 mm and a length of 233 6 10 mm. See Fig. 1. 5.3 Water Bath, equipped to control the temperature at 35 6 0.5°C. 5.4 Circulating Air Oven, capable ofmaintaining a tempera- ture of 99 6 1°C.
6. Test Specimen
6.1 The specimen shall consist ofthe 5-g leather sample that has been extracted with hexane as directed in Test Method D3495. Any deviation from this sample size should be included with the analytical results.
7. Procedure
7.1 Insert a plug of cotton or glass wool in the extraction tube before the specimen is added. Place the specimen in the extraction tube, slurry, and extract at 35°C by adjusting the flow to such a rate as to give 1 L of extract in 3 h. Cool the extract to 23°C, adjust to volume, and thoroughly mix. 7.2 If the extract is clear, pipet 100 mL into a tared crystallizing dish, evaporate and dry in a circulating air oven at 99 6 1°C for 16 to 18 h, transfer to a desiccator, cool, and weigh.7.3 If the extract is not clear, filter it. During this and subsequent operations, keep funnels and containers covered to prevent changes due to evaporations. Carry out all operations at an ambient temperature of 23 to 25°C. Place a 215-mm diameter filter paper, 4 pleated so that it contains 32 evenly divided creases, into a 125-mL funnel. To 2.0 g of kaolin (see Note 1) in a clean glass container add 25 mL of the extract and stir the mixture to a smooth paste. Add a further 200 mL of the extract and again stir the mixture to a uniform suspension. Pour the suspension onto the pleated paper in the funnel and collect the filtrate in the container in which the solution and kaolin were mixed. When 40 mL of the filtrate have been collected, swirl it to pick up kaolin remaining in the container, and return it to the funnel. Repeat collecting and repouring 40 mL of the filtrate onto the paper in the funnel as many times as possible for 1 h. Siphon the solution out of the filter without disturbing the kaolin film and discard it. Refill the paper with 225 mL of the extract, disturbing the kaolin film as little as possible by pouring into the center of the cone. When 40 mL of the filtrate have passed through, collect the next portion in a clear, dry glass container and, when about 125 mL have been collected, remove the container from beneath the funnel. Check this 125 mL for clarity and if not clear, reject it and rerun the determination using a new filter. N OTE 1—Only approved kaolin should be used. 5 When 1.0 g is suspended in 100 mL of distilled water for 5 min, the suspension shall have a pH between 4.5 and 6.0. When 2.0 g are shaken with 100 mL of distilled water for 10 min and the mixture filtered, 100 mL of clear filtrate shall leave less than 0.001 g of residue when evaporated and dried in a platinum dish.

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