Test method water absorption

Water absorption tests on our samples were performed according to the methods described in the experimental section. 

For standardization of the water uptake test, multiple organizations conducted the round robin test using common samples and procedures. Based on their results, methods (proposal) to determine water uptake and the rate of water absorption are being developed. A written inquiry was also distributed to the member companies of the Polymer Materials Center regarding water upUdce. Currently, Ihe standard for water uptake has not been established anywhere in the world. It seems important first to establish the standardization of Ihe water uptake testing method for superabsorbent polymers and then to make it die international standard. The testing mediods (proposal) shown here are still under discussion and when it is standardized by JIS, there may be partial modification. 

Analytical and Test Methods. Ash in isophthahc acid refers to the residue left after combustion of the sample. Ash consists of oxides of trace metals that are deterrnined individually by atomic absorption or inductively coupled plasma. A Kad Fischer titration is specific for the water content. 

AATCC methods for determining water repeUency are AATCC 22 (spray test) and AATCC 70 (tumble jar dynamic absorption test). In the spray test, water is sprayed against the taut surface of the test specimen to produce a wetted pattern the size of which depends on the repeUency of the fabric. Evaluation is by comparing the pattern with a series of patterns on a standard chart. The latter method evaluates the percentage by weight of water absorbed by a sample after dynamic exposure to water for a specified period of time. 

The dynamic absorption test measures the resistance of fabrics to wetting by water, not the repeUency of the total fabric surface. A weighed portion of fiber, yam, or fabric is tumbled ia water for 20 minutes it is then removed and reweighed to determine the percentage of water absorbed (AATCC Test Method 70). 

When water is used as the immersion liquid, the test is essentially the ASTM Standard Test Method (D570) for Water Absorption of Plastics.( ) Determinations of the relative rate of water absorption are important in evaluating the effects of moisture exposure on such properties as mechanical strength, electrical resistivity, dielectric... 

A molecular absorption spectrophotometry method, using a sharp-line irradiation source, has been developed for the determination of sulfide (as hydrogen sulfide) in water and sludge samples. The method was tested with measurements of real waste-water samples. The limit of detection was 0.25 g (1-10 mL sample volume). 

Functional property tests were conducted in duplicate. AACC (21) methods were used for the determination of water hydration capacity (Method 88-04) and nitrogen solubility index (NSI) (Method 46-23). Oil absorption capacity was measured by the procedures of Lin et al. (22) and oil emulsification by a modification (22) of the Inklaar and Fortuin (23) method. Pasting characteristics of 12.0% (w/v, db) slurries of the flours and processed products were determined on a Brabender Visco/Amylograph (Method 22-10). The slurries were heated from 30 to 95°C before cooling to 50°C to obtain the cold paste viscosity value. Gelation experiments were conducted by heating 15% (w/v db) slurries in sealed stainless steel containers to 90°C for 45 min in a water bath C3). 

An interesting point arises from this method. The particles of material are exposed to water vapour at a set humidity and hence the results equate to that humidity. The measured equilibrium absorption is substantially the same as the equilibrium absorption that would be obtained by immersion in an aqueous solution which would maintain the test humidity. As this implies, the equilibrium water absorption is reduced if the water is not pure. Hence, exposure to aqueous solutions should be made at the concentration of interest. As the humidity approaches 100% even small amounts of a salt have a significant effect on equilibrium absorption. 

One of the most common in vivo methods used to assess the permeability of the buccal mucosa is the buccal absorption test of Beckett and Triggs [13]. In this test, a known volume of a drug solution is introduced into the oral cavity of a subject, who swirls it around for a specified period of time and then expels it. The subject then rinses his or her mouth with an aliquot of distilled water or buffer solution, and the expelled drug solution and rinse are combined and analyzed for drug content. The difference between the initial and final drug concentration in the solution is assumed to be the amount of drug taken up into the oral mucosa. 

ISO 8361-2 1991 Thermoplastics pipes and fittings - Water absorption - Part 2 Test conditions for unplasticized poly(vinyl chloride) (PVC-U) pipes and fittings ISO 9393-2 1997 Thermoplastics valves - Pressure test methods and requirements - Part 2 Test conditions and basic requirements for PE, PP, PVC-U and PVDF valves ISO 9852 1995 Unplasticized poly(vinyl chloride) (PVC-U) pipes - Dichloromethane resistance at specified temperature (DCMT) - Test method ISO 9853 1991 Injection-moulded unplasticized poly(vinyl chloride) (PVC-U) fittings for pressure pipe systems - Crushing test... 

Rubber, vulcanized Determination of the effect of liquids Standard test method for rubber property-effect of liquids Standard test method for rubber property Change in length during liquid immersion Determination of the behavior of rubbers and elastomers when exposed to fluids and vapors Determination of the effect of liquids Determination of equilibrium water vapor absorption... 

Apparently the properties of moisture divided by pOH, reciprocal initial concentration, and water absorption as given in Equation 1 are only part of the story. Measurement of other properties, better able to indicate interactions between the surfaces of the toxicant and the carrier, might give significant correlations. These properties should probably include some function of available alkalinity and some function of the absorption capacity of the carrier and its degree of saturation. It is hoped that eventually someone will develop test methods for more useful properties of carriers that will correlate significantly with stability results. 

D 1584 Test Method for Water Absorptiveness of Paper Labels (Intent to Withdraw)... 

Specification for Elastomeric Joint Sealants Test Method of Compression Recovery of Tape Sealant Standard Test Method for Determination of Water Absorption of Sealant Backing (Joint Filler Material)... 

Assay Dissolve about 300 mg of sample, accurately weighed, in 50 mL of water in a 250-mL Erlenmeyer flask, and immediately titrate with 0.1 A iodine to a pale yellow color that persists for at least 30 s. Each milliliter of 0.1 A iodine is equivalent to 10.66 mg of C12H14Ca012-2H20. Lead Determine as directed in the Flame Atomic Absorption Spectrophotometric Method under Lead Limit Test, Appendix IIIB, using a 10-g sample. 

Free Fatty Acids (as stearic acid) Transfer 2 g of sample, accurately weighed, into a dry, 125-mL Erlenmeyer flask containing 50 mL of acetone, fit an air-cooled reflux condenser onto the neck of the flask, boil the mixture on a steam bath for 10 min, and cool. Filter through two layers of Whatman No. 42, or equivalent, filter paper, and wash the flask, residue, and filter with 50 mL of acetone. Add phenolphthalein TS and 5 mL of water to the filtrate, and titrate with 0.1 A sodium hydroxide. Perform a blank determination (see General Provisions) using 100 mL of acetone and 5 mL of water, and make any necessary correction. Each milliliter of 0.1 A sodium hydroxide is equivalent to 28.45 mg of stearic acid (CigH gOi). Lead Determine as directed in the Flame Atomic Absorption Spectrophotometric Method under Lead Limit Test, Appendix NIB, using a 10-g sample. 

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