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1、Copyright 2007 American Association of Textile Chemists and Colorists 118TM 89-2003AATCC Technical Manual/2008 Developed in 1958 by AATCC Commit- tee RA66; editorially revised 1974, 1984, 1986, 1988, 1990, 1992; reaf- firmed 1974, 1977, 1980, 1989, 1998, 2003; editorially revised and reaffirmed 1985
2、, 1994. 1. Purpose and Scope 1.1 This test method provides a method for the determination of the presence of mercerization in dyed and undyed cotton yarns and fabrics. In addition, the test will give an indication of the complete- ness of the reaction between the cotton and the mercerization bath. 2
3、. Principle 2.1 Carefully scoured specimens of the cotton to be tested and unmercerized cot- ton are immersed in separate baths of bar- ium hydroxide solution for a definite time period. Aliquot portions of each soaking bath and of fresh barium hydroxide solu- tion are then titrated with hydrochlori
4、c acid. 2.2 The ratio of the amount of barium hydroxide absorbed by the mercerized specimen to that absorbed by the unmer- cerized specimen multiplied by 100 gives the barium activity number. 3. Terminology 3.1 mercerization, n.a process for irreversibly altering the physical charac- teristics and a
5、ppearance of natural cellu- losic fibers by swelling in strong alkali. 4. Safety Precautions NOTE: These safety precautions are for information purposes only. The pre- cautions are ancillary to the testing proce- dures and are not intended to be all inclu- sive. It is the users responsibility to use
6、 safe and proper techniques in handling materials in this test method. Manufac- turers MUST be consulted for specific details such as material safety data sheets and other manufacturers recommenda- tions. All OSHA standards and rules must also be consulted and followed. 4.1 Good laboratory practices
7、 should be followed. Wear safety glasses in all laboratory areas. 4.2 All chemicals should be handled with care. 4.3 Use chemical goggles or face shield, impervious gloves and an imper- vious apron during dispensing and mix- ing of barium hydroxide, sodium carbon- ate and hydrochloric acid. Concentr
8、ated acids should be handled only in an adequately ventilated laboratory hood. CAUTION: Always add acid to water. 4.4 Petroleum solvent can be a com- bustible or flammable liquid, depending on which solvent is used, and presents a hazard. Ethanol and methanol are flam- mable liquids. Flammable liqui
9、ds should be stored in the laboratory only in small containers away from heat, open flame and sparks. These chemicals should not be used near an open flame. 4.4.1 Carry out reflux procedure in a well ventilated hood with an electrical heating mantle or a water bath as the heat source. 4.4.2 Use chem
10、ical goggles or face shield, impervious gloves and an imper- vious apron when handling organic sol- vents. 4.5 An eyewash/safety shower should be located nearby and an organic vapor respirator and a self-contained breathing apparatus should be readily available for emergency use. 4.6 Exposure to che
11、micals used in this procedure must be controlled at or below levels set by governmental authorities e.g., Occupational Safety and Health Administrations (OSHA) permissible exposure limits (PEL) as found in 29 CFR 1910.1000 of January 1, 1989. In addition, the American Conference of Governmental Indu
12、strial Hygienists (ACGIH) Threshold Limit Values (TLVs) comprised 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 13.7). 5. Limitations 5.1 The test cannot b
13、e used satisfacto- rily if durable finishes or fibers other than cotton are present. 6. Apparatus 6.1 Burette (preferably automatic) (see 13.4). 6.2 Flask, Erlenmeyer, with reflux tube. 6.3 Flasks, glass-stoppered, 250 mL. 6.4 Flasks, Erlenmeyer, 125 mL. 6.5 Bottles, storage, 250-500 mL. 6.6 Beaker,
14、 1500 mL. 6.7 Pipette, 10 mL. 6.8 Drying oven. 7. Reagents and Materials 7.1 Hydrochloric acid (HCl) standard- ized approx. 0.1N. 7.2 Barium hydroxide reagent Ba(OH)2 approximately 0.25N (see 13.1). 7.3 Phenolphthalein. 7.4 Petroleum solvent BP 30-60C (86-140F). 7.5 Alcohol (95% ethanol or anhy- dro
15、us methanol). 7.6 Enzyme, starch-solubilizing. 7.7 Soap, neutral, granular (see 13.2). 7.8 Water, distilled. 7.9 Cotton yarn, unmercerized for ref- erence (standard cotton) (see 13.3). 8. Test Specimens 8.1 A minimum of 5 g of each sample and of the unmercerized standards are scoured as directed aft
16、er which a 2 g specimen of each scoured sample is weighed and placed in clean, dry glass- stoppered flasks. 9. Procedure 9.1 Scouring. The purpose of the scouring operation is to remove all extra- neous matter, leaving the cotton cellulose in as pure a form as possible and without changing it chemic
17、ally. 9.1.1 The samples to be tested (at least 5 g each), together with the standard un- mercerized cotton, are refluxed together successively for 1 h with petroleum sol- vent boiling point 30-60C (86-140F), 1 h with alcohol (95% USP ethanol, No. 30 specially denatured alcohol, 95% or anhydrous meth
18、anol may be used), and for 1 h with distilled water (see 13.4). 9.1.2 Following these three extrac- tions, starches are removed as follows: 9.1.3 Cover the sample with distilled water containing 3% of a commercial starch-solubilizing malt enzyme solution and heat to 60 5C (140 9F). Main- tain the so
19、lution at this temperature for a period of 1 h. Pour off the enzyme solu- tion, rinse and then scour as follows. 9.1.4 Boil the samples together for 1 h in 1 L of water containing 10 g of a neu- tral soap and 2 g of soda ash. Wash re- peatedly in warm water until free from soap and alkali, i.e., unt
20、il neutral to phe- nolphthalein, squeeze and dry. The sam- ples and the standard unmercerized cot- ton are dried in an oven at 100C (212F) until thoroughly dry. The samples are then allowed to come to room conditions. Each sample should then be cut into AATCC Test Method 89-2003 Mercerization in Cot
21、ton Copyright 2007 American Association of Textile Chemists and Colorists AATCC Technical Manual/2008TM 89-2003119 small pieces approximately 3 mm (0.125 in.) square for subsequent weighing. 9.2 Testing. Prepare and test duplicate specimens from each sample. Weigh 2 g of each scoured sample and of t
22、he scoured standard cotton into dry 250-mL flasks equipped with stoppers. (Ground glass stoppers are recommended.) Add 30 mL 0.25N barium hydroxide (see 13.5) to each flask containing a test spec- imen and to two empty flasks for blank determinations. Stopper each flask imme- diately upon addition o
23、f the barium hy- droxide and store them for at least 2 h in a water bath at 20-25C (68-77F) (room temperature). Shake the flasks at frequent intervals. After 2 h, transfer 10 mL of so- lution (see 13.6) from each container, in- cluding the blanks and titrate with 0.1N hydrochloric acid, using phenol
24、phthalein as an indicator. 10. Calculations 10.1 Using the titration figures, deter- mine the ratio of barium hydroxide ab- sorbed by a mercerized specimen to that absorbed by the unmercerized standard. Multiply this ratio by 100 to obtain the barium activity number. Example: 10 mL of barium hydroxi
25、de solution (blank) required 24.30 mL of 0.1N HCl; 10 mL of barium hydroxide from an unknown sample of cotton re- quired 19.58 mL of 0.1N HCl; 10 mL of barium hydroxide from unmercerized cotton (standard) required 21.20 mL of 0.1N HCl. Therefore the barium number of the unknown sample is: 10.2 Bariu
26、m numbers should be run in duplicate and should be reported sepa- rately. Duplicate runs should not be off by more than four units. The titrations should be within 0.1 mL for check re- sults. Skilled operators can estimate to within 0.05 mL. A difference of more than four units between duplicate run
27、s in- dicates inaccuracy in running the test (see Table I). 11. Interpretation 11.1 A barium activity number in the range of 100-105 indicates no merceriza- 24.3019.58 24.3021.20 - -100152= tion. A barium activity number above 150 indicates substantially complete re- action between the cotton and th
28、e mercer- izing bath. Intermediate numbers indicate either incomplete reaction or use of a weak mercerizing bath. 12. Precision and Bias 12.1 Precision. Precision for this test method has not been established. Until a precision statement is generated for this test method, use standard statistical te
29、ch- niques in making any comparisons of test results for either within-laboratory or between-laboratory averages. 12.2 Bias. Mercerization in cotton can be defined only in terms of a test method. There is no independent method for de- termining the true value. As a means of estimating this property,
30、 the method has no known bias. 13. Notes 13.1 The barium hydroxide reagent is pre- pared by shaking distilled water with slightly more than the calculated quantity of barium hydroxide, allowing it to stand overnight in a stoppered bottle, and then siphoning the clear solution into a clean storage bo
31、ttle. 13.2 Available from AATCC, P.O. Box 12215, Research Triangle Park NC 27709; tel: 919/549-8141; fax: 919/549-8933; e-mail: or- dersaatcc.org. 13.3 Unmercerized standard cotton skeins (40/2 ply) as used for the Draves Wetting Tests are particularly satisfactory. They may be obtained from Testfab
32、rics Inc., P.O. Box 26, 415 Delaware St., W. Pittston PA 18643; tel: 570/603-0432; fax: 570/603-0433; e-mail: . 13.4 If it is known that all samples that test do not contain finish or starch, then the scour- ing procedure may begin with the soap-and- soda ash treatment. If one sample requires sol- v
33、ent extraction and the enzyme treatment, then all samples including the standard cotton must be treated together with the complete scouring procedure to insure the same final state for the whole set of samples. 13.5 An automatic burette is most conve- nient for the addition of the barium hydroxide s
34、olution to the specimens. The air outlet must be equipped with an absorption tube contain- ing soda lime to remove carbon dioxide. The latter must not be allowed to enter any burette that might be used, because formation of bar- ium carbonate not only affects the concentra- tion of the reagent but f
35、orms a film which interferes with burette readings. A cork is fitted to the bottom of the burette in such a manner that the 250 mL Erlenmeyer flasks containing the specimens under test are locked into place without exposure to air during the addition of barium hydroxide. The barium hydroxide solu- t
36、ion should cover the specimens, tilting the flasks if necessary to accomplish this end. 13.6 For the removal of 10 mL of barium hydroxide when equilibrium has been reached, a 10 mL pipette is used. The same pi- pette, burette, etc., should be used for the whole set of determinations and the same tec
37、hnique for emptying or filling pipettes and burettes should be used on each determina- tion. The hydrochloric acid burette is also equipped with a cork to which the 125 mL flask can be attached during the titration of the 10 mL aliquot portions of barium hydroxide, thereby eliminating titration erro
38、rs resulting from carbon dioxide absorption by the alka- line solution. In removing the 10 mL aliquot portion of barium hydroxide from flasks con- taining specimens, the operator should use the end of his pipette to push the cotton against the wall of the flask and to express the excess liquor. In t
39、his way, a larger amount of the solu- tion will be available for drawing up into the pipette. 13.7 Available from Publications Office, ACGIH, Kemper Woods Center, 1330 Kemper Meadow Dr., Cincinnati OH 45240; tel: 513/742-2020. Table IBarium Numbers: Interlaboratory Tests on Mercerized Fabrics ClothL
40、ab ALab BLab C1Lab C2Lab C3 80 8035 Tw118118117120114 80 8055 Tw130131128132125 108 5855 Tw141145143143140 136 6455 Tw122123123122120 88 5055 Tw139140136140133 1Fabrics scoured by Lab C, unmercerized 80 80 as standard. 2Fabrics scoured by Lab A, unmercerized 80 80 as standard. 3Fabrics scoured by Lab C, 40/2 combed mercerized yarn as standard.