ASTM D2165-94(2000)
(Test Method)Standard Test Method for pH of Aqueous Extracts of Wool and Similar Animal Fibers
Standard Test Method for pH of Aqueous Extracts of Wool and Similar Animal Fibers
SCOPE
1.1 This test method covers the determination of the pH of aqueous extracts from wool and similar animal fibers. It is applicable to fibers in any condition-raw wool, scoured wool, sliver, top, yarn, or fabric.
1.2 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 appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see Section 11.
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Designation:D2165–94 (Reapproved 2000)
Standard Test Method for
pH of Aqueous Extracts of Wool and Similar Animal Fibers
This standard is issued under the fixed designation D 2165; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 4. Summary of Test Method
1.1 This test method covers the determination of the pH of 4.1 An extract is prepared using distilled water or 0.1 N
aqueous extracts from wool and similar animal fibers. It is sodium chloride solution at the boil under reflux, or at room
applicable to fibers in any condition—raw wool, scoured wool, temperature with agitation. The pH of the extract is measured
sliver, top, yarn, or fabric. electrometrically with a glass electrode.
1.2 This standard does not purport to address all of the
5. Significance and Use
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 5.1 The pH values of the extracts give an indication of the
acidity or alkalinity of the fiber and its water-soluble impuri-
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. For specific ties. These values are useful in indicating previous processing
and in anticipating subsequent performance. For particular
precautionary statements, see Section 11.
purposes, the pH of an extract prepared by one method may be
2. Referenced Documents
a more informative index than another and as a consequence
2.1 ASTM Standards: four optional extraction procedures are included.
D 123 Terminology Relating to Textiles 5.2 This test method is not recommended for acceptance
D 2525 Practice for Sampling Wool for Moisture testing because the between-laboratory precision is relatively
E 70 Test Method for pH of Aqueous Solutions with the poor. In some cases, the purchaser and the seller may have to
Glass Electrode test a commercial shipment of one or more specific materials
by the best available method, even though the method has not
3. Terminology
been recommended for acceptance testing of commercial
3.1 Definitions: shipments. In such a case, if there is disagreement arising from
3.1.1 aqueous extract, n— in wool testing, the solution differences in values reported by the purchaser and the seller
obtained by digesting a material with water or with a sodium
when using this method for acceptance testing, the statistical
chloride solution to dissolve soluble materials. bias, if any, between the laboratory of the purchaser and the
3.1.2 pH, n—in common usage, a measure of acidity or
laboratory of the seller should be determined, with each
alkalinity of a solution, on a logarithmic scale, with neutrality comparison being based on testing specimens randomly drawn
represented by a value of seven, with increasing acidity
from one sample of material of the type being evaluated.
represented by decreasingly smaller values, and with increas-
6. Apparatus and Materials
ing alkalinity represented by increasingly larger values.
3.1.2.1 Discussion—For a technical discussion of pH, in- 6.1 All glassware coming in contact with the liquid shall be
cluding such phenomena as the effect of temperature on pH, of a chemical-resistant glass, in which the contacting surfaces
see any recognized chemistry text. The pH of textiles is have been soaked for two days in 0.1 N hydrochloric acid and
generally determined on aqueous extracts of the textile being then rinsed thoroughly with distilled water (see 7.1) until the
tested. rinsings have a pH of 6.0 or higher.
3.1.3 For definitions of other textile terms used in this test
NOTE 1—It is desirable but not mandatory that the glassware be
method, see Terminology D 123.
reserved for extraction tests only and be filled with distilled water during
storage between tests.
6.2 Apparatus for Extraction at Room Temperature:
ThistestmethodisunderthejurisdictionofASTMCommitteeD-13onTextiles
6.2.1 Erlenmeyer Flasks, 250-ml, wide-mouth, with
and is the direct responsibility of Subcommittee D13.13 on Wool and Wool Felt.
ground-glass stoppers.
Current edition approved Dec. 15, 1994. Published April 1995. Originally
published as D 2165 – 61 T. Last previous edition D 2165 – 90.
Annual Book of ASTM Standards, Vol 07.01.
3 4
Annual Book of ASTM Standards, Vol 15.05. Borosilicate glass has been found satisfactory.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D2165
6.2.2 Laboratory Shaker or Agitator, with apparatus for
n 5 ~ts/E! (1)
attaching the flasks, holding at least three flasks, to provide
where:
agitation that will not raise the temperature more than 5.5°C in
n 5 number of specimens per laboratory sampling unit
2h.
(rounded upward to a whole number),
6.3 Additional Equipment Needed for Extraction at The
s 5 reliable estimate of the standard deviation of individual
Boil:
observations on similar materials in the user’s labora-
6.3.1 Erlenmeyer Flask, 500-mL, with ground-glass joint.
tory under conditions of single operator precision,
6.3.2 Air Condenser, Glass, reflux, to fit the flask.
t 5 value of Student’s t for two-sided limits, a 95 %
6.3.3 Tube, to hold absorbent for acidic and basic gases.
probability level, and the degrees of freedom associ-
6.3.4 Glass Stopper, for flask, equipped with a stopcock and
ated with the estimate of v (Table 1), and
thermometer with a range from 0 to 105°C.
E 5 0.5 percentage points, the allowable variation.
6.4 pH Meter and Glass Electrode, conforming to the
9.1.2 No Reliable Estimate of s—When there is no reliable
requirements of Sections 5 and 6 of Test Method E 70.
estimate of s for the user’s laboratory, Eq 1 should not be used
directly. Instead, specify the fixed numbers of specimens
7. Reagents
shown in Table 2. These numbers of specimens are calculated
7.1 Distilled Water, having a pH of between 6.2 and 7.0. If
using values of s which are listed in Table 2 and which are
not in that range of pH, redistillation is necessary.
somewhat larger values of s than are usually found in practice.
7.2 Sodium Chloride, Standard Solution (0.1 N), prepared
When a reliable estimate of s for the user’s laboratory becomes
from reagent grade sodium chloride (NaCl) and distilled water
available, Eq 1 will usually require fewer specimens than are
having a pH of between 6.2 and 7.0.
listed in Table 2.
7.3 Anhydrous Calcium Sulfate or Equivalent Absorbent for
Acid or Alkaline Gases.
10. Preparation of Extracts
10.1 Extraction with Boiling Water— Include an approxi-
8. Sampling and Specimen Preparation
mately proportionate quantity of any fallout present in each
8.1 Takealotsampleofrawwool,scouredwool,sliver,top,
specimen. Transfer each specimen to a separate flask. Cover
yarn, or fabrics as specified in the sampling procedure in
the fibers with 200 mL of boiling water (see 7.1). Connect the
Practice D 2525.
reflux condenser, making certain that anhydrous calcium sul-
8.2 Select specimens at random from the unconditioned
fate absorbent is in the absorption tube. Shake, to complete
sample, each weighing 10 6 0.1 g. Cut the fibers of the
wettingofthefiber,andheatgentlytomaintainboiling.Agitate
specimen into lengths of about 5 mm and blend.
the solution every 10 min by shaking the apparatus.After 30 to
35 min, remove the flask from the heat source, remove the
9. Number of Specimens
reflux condenser, and stopper the flasks as quickly as possible
9.1 Take a number of specimens per laboratory sampling with a stopper containing a thermometer. Cool the flask and
unit such that the user can expect at the 95 % probability level contents in water maintained at 21 6 2°C, without removing
that the test result for a laboratory sampling unit will be no the stopper. Measure the pH within 10 min after extraction and
more than 0.5 percentage points above or below the true cooling have been completed, as directed in Section 11.
average for the laboratory sampling unit as follows: 10.2 Extraction with Water at Room Temperature—Takethe
9.1.1 Reliable Estimate of s—When there is a reliable two specimens, including an approximately proportionate
estimate of s based upon extensive past records in the user’s quantity of any fallout present. Transfer each specimen to a
laboratory as directed in the test method, calculate the required separate flask. Cover the fibers with 100 mLof neutral distilled
number of specimens per laboratory sampling unit using Eq 1:
water at 21°C. Then stopper the flask using a glass stopper
having a built-in thermometer. Shake vigorously by hand for
about 30 s to wet the specimen thoroughly and then agitate
TABLE 1 Values of Student’s t for One-Sided and Two-Sided
mechanically for2hata rate that will not warm the solution
A
Limits and the 95% Probability
above 28°C. Measure the pH as directed in Section 11.
One- Two- One- Two- One- Two-
df df df 10.3 Extraction with Boiling 0.1 N NaCl Solution—Proceed
Sided Sided Sided Sided Sided Sided
as dir
...
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