Swelling Test

Free-swelling tests are commonly used to measure a coal s caking characteristics. A sample of coal is packed in a cmcible or tube, without compaction, and heated at a fixed rate to about 800°C. Infusible coals distill without changing appearance or state of agglomeration. The fusible coals soften, fuse, and usually sweU. The profile of the resultant coke is compared to a series of reference profiles so that a swelling index can be assigned. The profiles represent indexes between 0 and 9. The best cokes come from coals having indexes between 4 and 9. 

Results from Differential Swelling Test of Various Rubber Blends... 

The application of a modified swelling test allows us to demonstrate that the network formation starts after the tPmax value (time necessary to obtain the rPmax value see Fig. 1). This experiment demonstrates that the decrease in the rP values is a result of the network formation. 

The application of a modified swelling test [3] allows us to estimate the network density as a function of exposure time and of the thiol content. Highest values are achieved in stoichiometric mixtures. 

Gad, S. C. et al., Development and validation of an alternative dermal sensitization test the mouse ear swelling test (MEST), Toxicol. Appl. Pharmacol., 84, 93, 1986. 

Cell-mediated immunity Cytotoxic T lymphocyte killing delayed type hypersensitivity response mouse ear swelling test (MEST Gad et al., 1986) guinea pig maximization test (Magnusson and Kligman, 1969). 

Gad S.C., Dunn, B.J., Dobbs, D.W. and Walsh, R.D. (1986) Developmental and validation of an alternative dermal sensitization test The Mouse Ear Swelling Test (MEST), Topical Appl. Pharmacol. 84 93-114. 

Swelling tests and determination of tensile properties. The procedure for estimating cross-link density from equilibrium swelling data is described in detail in a previous paper (6). The tensile properties of the PU films were carried out at 23°C and 60% relative humidity. The crosshead speed and distance were 10 mm/min and 30 mm, respectively. A more detailed description of the tensile tests is given elsewhere (6). 

Crosslink density of PU films. The PU films were subjected to swelling tests in dimethylformamide. The crosslink densities of the films were thereafter estimated from equilibrium swelling data using a modified version of the Flory-Rehner equation. The swelling tests as well as the calculation of crosslink density are described in detail in a previous paper (6). 

Hot rolling particles from the recovery test on the cuttings were used. Samples were extruded in a CT 15 compressometer device at a rate of 40 mm /min where the pressure necessary to extrude the particles was recorded. The harder the particles, the higher the pressure, the better the protection with regard to penetration of water, and the better the inhibiting effect on clay swelling. Testing results are provided in Table 2. 

Though a standard norm or absolute reference value is not available for comparison in any of the international standard specifications and the technical and research publications with respect to the chemical resistance properties of rubber, liquid immersion tests certainly provide relative and useful data with which the suitability of anticorrosive rubber lining compounds can be assessed with a fair degree of accuracy. For this reason manufacturers and applicators of rubber lining resort to tests under simulated conditions instead of accelerated ageing immersion or swelling tests. 

Dimensions such as the width of a dumb-bell or the depth of a nick in a tear specimen will be less than 30 mm but could not be measured with a dial gauge. Because of the virtual impossibility of applying a known pressure, such measurements must be made in an essentially contactless manner. For low precision, calipers or a rule may suffice but for readings to 0.01 mm a travelling microscope or projection microscope is most suitable, and this is specified in ISO 23529 Method D and applies also to dimensions over 30mm. Projection microscopes also find use in examining profiles and for rapid swelling tests (see Chapter 16, Section 2.1). 

Differences in results can occur between tests in a liquid and a gaseous medium. This is often because different times are required to reach equilibrium temperature, and if crystallisation is occurring, for example, the stiffness will be dependent on time of conditioning. It is also essential that if a liquid medium is used the liquid does not affect the rubber by swelling it or removing extractables, as either process can have a considerable effect on low temperature behaviour. Ethanol is most widely used but acetone, methanol, butanol, silicone fluid and n-hexane are all suggested in ISO 2921. Not all of these will be suitable for all rubbers and the suitability of any proposed liquid must be checked by preliminary swelling tests. 

Tests in which rubbers are exposed to liquids are often called swelling tests simply because the resulting change in volume of the test piece is by far the most commonly used measure of the effect of the liquid. Similarly, the tests are also referred to as oil ageing because standard grades of mineral oil are the liquids most often specified. 

The constitutive equations use a thermodynamic framework, that in fact embodies not only purely mechanical aspects, but also transfers of masses between the phases and diffusion of matter through the extrafibrillar phase. Since focus is on the chemo-mechanical couplings, we use experimental data that display different salinities. The structure of the constitutive functions and the state variables on which they depend are briefly motivated. Calibration of material parameters is defined and simulations of confined compression tests and of tree swelling tests with a varying chemistry are described and compared with available data in [3], The evolution of internal entities entering the model, e.g. the masses and molar fractions of water and ions, during some of these tests is also documented to highlight the main microstructural features of the model. 

After the boards were removed from the hot press they were conditioned at room temperature for several days before testing. Three 2 x 10-inch strips were cut from each board for determining breaking load. A 0.24-inch-per-minute loading rate and a 9-inch span were used. Thickness of each strip was measured at the point where the load was to be applied, and after the strip had been "broken each half was cut into two 2 x 2-inch samples. These samples were used to obtain data necessary for determination of oven-dry density, water absorption and thickness swelling, internal bond, and a 2-hour boiling-in-water thickness swelling test. 

Cornacoff JB, House RV, Dean JH (1988) Comparison of a radioisotopic incorporation method and the mouse ear swelling test MEST) for contact sensitivity to weak sensitizers. Fund Appl Toxicol 10 40-44 Dunn BJ, Rusch GM, Siglin JC, Blaszcak DL (1990) Variability of a mouse ear swelling test (MEST) in prediction of weak and moderate contact sensitizers. Fundam Appl Toxicol 5 242-248... 

DCC has a higher contact hypersensitivity in the mouse ear swelling test than DICDI. Exposure to diisopropylcarbodiimide can cause temporary blindness. ... 

Swelling tests on the vulcanizates produced are an alternative option. The mean distance between two crosslinks can be applied to determine the concentration of crosslinks [9]. The reaction can only be studied once the gel point has been reached, since only then does a three-dimensional network form. 

Chi, M.S. Compatibility of cross-hnked polymers with plasticizers by glass transition temperature measurement and swelling tests. J. Polym. Sci. Pol. Chem. Ed. 1981, 19, 1767-1779. 

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