FEBRUARY 99
CENTRIFUGE RETENTION CAPACITY
441.1-99 RECOMMENDED TEST METHOD:
Superabsorbent materials - Polyacrylate superabsorbent powders -
CENTRIFUGE RETENTION CAPACITY IN SALINE BY GRAVIMETRIC DETERMINATION
1SCOPE
The method determines the fluid retention capacity of polyacrylate (PA) superabsorbent powders in sali
ne solution, following centrifugation.
2NORMATIVE REFERENCES
ISO 9092Textiles - Nonwovens - Definition.
ISO 3696Water for analytical laboratory u - Specification and test methods.
ISO 187Paper, Board and pulps - Standard atmosphere for conditioning and testing and procedure for monitoring the atmosphere and conditioning of samples.
ISO 5725Precision of test methods - Determination of repeatability and reproducibility for
a standard test method by interlaboratory tests.
3DEFINITION
Teabag: Bag of nonwoven (according to ISO 9092) as defined in 6.1.
4PRINCIPLE
The sample is weighed and placed in a teabag. The teabag is submerged in the fluid to be absorbed and afterwards centrifuged for a specified time, at a specified centrifugal force, to determine the amount of fluid retained.
5REAGENTS AND MATERIALS
5.1.Analytical grade NaCl.
5.2.Saline Solution 0,9 %.
Preparation of saline solution:
(9 ± 0,1) g NaCl (analytical grade) is added to deionized water (grade 3, ISO 3696) to
give a total mass of 1000 g ± 1g and stirred until dissolved.
6APPARATUS AND MATERIALS
6.1.Teabag from (60 x 40) mm² to (60 x 85) mm² heatalable nonwoven, folded and heat
aled on two of three open sides so the inside edges of the als are about 3 to 5 mm
from the edge of the teabag.
441.1-99FEBRUARY 99 Nonwoven characteristics: Mass per unit area: (16,5 ± 1,5) g/m²
Thermoplastic fibres content: (4 ± 0,8) g/m²
Wet tensile strength in cross direction: (70 ± 12) N/m
Air permeability: (230 ± 50) L/min / 100cm² (4 plies tested)
6.2Heat aler capable of bonding nonwoven.
Large pan, approximately 5 to 15 cm deep and large enough to hold veral teabags.
6.4Analytical balance, capable of measuring a mass of 100g to an accuracy of ± 0,001g.
6.5Weighing boats or weighing paper.
6.6Timer accurate to 1 cond over 30 minutes.
6.7Centrifuge equipped with basket rotor, capable of delivering a force F equal to a
centrifuge acceleration of 250g applied to a mass placed on the internal wall of the basket
(e.g. 1400 rpm for a basket internal diameter of 225 mm).
For calculation of the centrifuge acceleration e annex 1.
7SAMPLING AND SAMPLES
Safety Caution: U respiratory protection, dust mask or fume hood, when handling sample amounts greater than 10 g.
In order to guarantee that a reprentative sample is taken from the bulk material, the top layer (approximately 20 cm) in a big bag or a silo truck is removed. The sample is taken with a scoop and filled into an airtight container within 3 minutes. The size of the container should be adequate for the size of the sample.
Laboratory samples must be kept in a clod container and allowed to equilibrate to the laboratory temperature before removing a test portion to run the test. The preferred test conditions are 23 ± 2°C and 50 ± 10 % relative humidity. If the are not available, test at ambient conditions and report the temperature and relative humidity. The procedure for measurement of the laboratory conditions is sp
ecified in ISO 187.
村务公开栏The container is shaken 3-5 times in order to obtain a homogeneous product. Leave container at rest for 5 minutes before opening the lid and removing the sample portion.
All samples should be substantially free of lumps of size greater than 1 mm in diameter before proceeding with testing.
8PROCEDURE
8.1Weigh 0,200 g ± 0,005 g of absorbent material and record the mass (Wd)1.
8.2Prepare 2 or more teabags as specified in 6.1.
Note: Samples prepared for ERT 440 can be continued in this test. If so, proceed to
8.11.
8.3Place the test portion into the bag and al the bag.
FEBRUARY 99
441.1-99
8.4
U the same procedure to prepare a cond sample (Wd)2.
钛合金是什么材料>继续拼音If it takes longer than 5 minutes to weigh and al the bags before starting the test, place the teabags in a desiccator.
小兴安岭旅游8.5
Prepare 2 blank teabags and test alongside the bags containing superabsorbent powders.
Note:As long as teabag materials and aling conditions are unchanged, the u of
historical data on the blanks may be considered. In this ca, the tests on the two blanks need not be carried out.8.6Fill the pan with 0,9 % saline solution.
Change the solution after a maximum of 10 teabags per liter of u.
8.7Hold the teabags containing the test portion by opposite edges and distribute the test portion hori
zontally throughout the teabags.
8.8
Lay the teabags on the surface of the saline solution. Allow the teabags to wet out for one minute before pushing it under the liquid surface. Eliminate entrapped air bubbles by manipulation of the teabag.
8.9
After 30 ± 1 min, remove the teabags.
8.10Set the centrifuge control to obtain 250g centrifuge acceleration. (according to 6.7)8.11Place the samples and the blanks in the centrifuge basket.
Position the teabags so that the blanks are opposite each other, and the bags containing the samples are opposite each other for proper balancing.8.12Switch off the centrifuge after 3min ± 10s.8.13Wait for complete stop before opening the lid.
8.14Remove the teabags, weigh each and record the mass of the two blank teabags (Wbc)
1 and 2, and the mass of the teabags containing SAP (Wwc), for the calculation.9
CALCULATION AND RESULTS
Calculate the average of the 2 wet blank teabag mass after centrifugation社会焦虑
For each sample (i = 1and 2), calculate:Centrifuge Retention Capacity :where:
W d = Dry test portion mass in g,
W bc = average of the 2 wet blank teabag mass (after centrifugation) in g,
W wc = Mass of wet teabag containing absorbent material (after centrifugation) in g.Take the average of the 2 calculated values to 0,1 unit accuracy.
2
2
Wbc 1Wbc Wbc +=
i
)Wd (i
)Wd (bc W i )wc W ()g /g (CRC −−=
441.1-99FEBRUARY 99
10PRECISION
The data for the repeatability and reproducibility limit of this method are the result of interlaboratory tests carried out in 1997 by the EDANA, and are given in annex (e 12). The evaluation of the laboratory test was carried out according to ISO 5725.
The absolute difference between two single test results obtained under repeatability test conditions according to ISO 5725-2 shall not be greater than 1.53 units, with a probability of 95%.
The absolute difference between two single test results obtained under reproducibility test conditions according to ISO 5725-2 shall not be greater than 3.28 units, with a probability of 95%.
If the repeatability and reproducibility test criteria are not met, the test shall be repeated twice, each in duplicate, after ensuring that the original sample is thoroughly mixed. If it still fails to satisfy the criteria report as unusual.
11TEST REPORT
The test report shall include the following information:
a) Type of PA superabsorbent powders tested.
b) Reference to this ERT
c) Centrifuge retention apacity in g/g to 0,1 unit accuracy.
d) Any deviation from the standard method.
Figure 1: Positioning of the teabags in the centrifuge basket
FEBRUARY 99441.1-99 12INFORMATIVE ANNEX
12.1Centrifuge acceleration
The centrifuge force (F) applied to a mass (m) placed on the internal face of the
cylindrical basket is defined by:
F = mw² R
加油朋友
where:m = mass
w = angular speed (radians per cond)
R = basket radius (metre)
According to 5.7, the specified centrifuge force corresponds to 250 g acceleration applied
to the mass, i.e.
非物质文化
mw² R = m x 250 g
g = acceleration due to gravity (9,81 m c-2)一次函数教案
The characteristics of the centrifuge are then defined by:
w2 R = 250 g
12.2Precision
Figures for the repeatability and reproducibility of this method are the result of
collaborative studies carried out in 1997 by EDANA, with the following data:
Sample A B C
No. of participating laboratories101010
No. of non-eliminated laboratories101010
No. of single values of the non-eliminated laboratories403940
Average (g/g)27,2631,8731,65
Standard deviation of repeatability, s r0,550,240,39
Coefficient of repeatability, CV r2,01%0,76%1,24%
Repeatability, r (2,8 x s r)1,530,681,09
Standard deviation of reproducibility, s R1,150,911,17
Coefficient of reproducibility, CV R4,22%2,86%3,71%
Reproducibility, R (2,8 x s R)3,222,553,28
