AATCC 43 pdf free download
AATCC 43 pdf free download.Wetting Agents for Mercerization.
1. Purpose and Scope
1 . I This test method is applicable only to the evaluation of wetting agents in caustic soda of mercerizing concentration.
2. Principle
2.1 A 25mm (1 in.) long bundle of cotton yarns composed of 120 ends is carefully dropped onto the surface of a test solution and the time for complete wetting of all ends is determined.
3. Terminology
3.1 mercerization, n.—a process for irreversibly altering the physical characteristics and appearance of natural cellulosic fibers by swelling in strong alkali.
3.2 wetting agent, n.—a chemical compound which when added to water lowers both the surface tension of the liquid and its interfacial tension against the solid material.
4. Safety Precautions
NOTE: These safety precautions are for information purposes only. The precautions are ancillary to the testing procedures and are not intended to be all inclusive. It is the user’s responsibility to use safe and proper techniques in handling materials in this test method. Manufacturers MUST be consulted for specific details such as material safety data sheets and other manufacturer’s recommendations. All OSHA standards and rules must also be consulted and followed.
4.1 Good laboratory practices should be followed. Wear safety glasses in all laboratory areas.
4.2 All chemicals should be handled with care. Use chemical goggles or face shield, impervious gloves and an impervious apron during dispensing and mIxing of sodium hydroxide.
4.3 An eyewashJsafety shower should be located nearby and a self-contained breathing apparatus should be readily available for emergency use.
4.4 Exposure to chemicals used in this procedure must be controlled at or below levels set by governmental authorities (e.g., Occupational Safety and Health Administration’s [OSHA] permissible exposure limits [PEL] as found in 29 CFR 1910.1000 of January 1, 1989). In addition, the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values (TLVs) compriscd of time weighted averages (TLV-TWA), short term exposure limits (TLV-STEL) and ceiling limits (TLV-C) are recommended as a general guide for air contaminant exposure which should be met (see 9.2).
5. Apparatus and Materials
5.1 Beakers, 250 mL.
5.2 Mohr measuring pipettes (0.1 graduation), 1 or 2 mL.
5.3 Volumetric transfer pipettes, 100 mL.
5.4 Stopwatch.
5.5 Scissors.
5.6 Ruler.
5.7 Cotton yarn. greige (unboiled), 40/2 combed peelei preferably in form of chain warp or skein (see 9.1).
5.8 Standard mercerizing penetrant against which comparisons can be made.
5.9 Mercerizing caustic soda with a specific gravity of 48-52% Tw (271-299 g NaOlI per liter of soln). Allow to stand several hours (until clear) after preparation.
5.10 Log-log coordinate paper No. 46-
7083 from Keuffel & Esser Co., or No.
340-L2 1 from Eugene Dietzgen Co.
6. Procedure
6.1 Into each of three 250 mL beakers measure out 100 mL of the mercerizing caustic soda solution at 26 ± 3°C (78 ± 5°F). Pipette into one beaker 0.75 mL, into the next 1.00 mL and into the third beaker 1.25 mL of the mercerizing penetrant using a suitable small pipette. Mercerizing wetting agents all seem to be liquids. Stir the contents of each beaker until the penetrant is completely dissolved in the caustic soda. These solutions are allowed to stand until all air bubbles have risen to the surface. It should be particularly noticed if the penetrant remains well dispersed or dissolved because the separation of an immiscible layer on the surface would entirely vitiate the results and give flse values.
6.2 From the greige (unboiled), 40/2, combed peeler cotton yarn, cut a bundle of 120 parallel ends, 25 mm (1 in.) in length. This bundle of yarn ends is dropped carefully onto the surface of one of the caustic solutions of penetrant, and the time required for complete wetting of all the ends is noted with a stopwatch. The average of five determinations is taken as the sinking time for that concentration.AATCC 43 pdf download.
