Fluid resistance tests

Figure 10.8 Scanned image of the surface of two alloy panels showing adhesion failure caused by the omission of O2 plasma treatment of the substrate prior to plasma film deposition and application of the primer (Deft 44-GN-72 MIL-P-85582 Type I Waterbased Chromated Control Primer), a) Panel after Skydrol LD4 fluid resistance test, which had the O2 plasma treatment prior to film deposition and primer application, b) Panel after scribed wet (24-h immersion in tap water) tape test, which had not been treated with the O2 plasma treatment prior to film deposition and primer application.

Results of the KC Blood Strike Through Test, the Impact Penetration Test, the Hydrostatic Pressure Test, the Biological Fluid Resistance Test (2 psi) were highly correlated (i.e., they differentiated between different types of gowns in a similar manner). 

Fluid Resistance (Chemical Resistance). Fluid resistance is the extent to which a rubber product retains its original physical characteristics and abihty to function after exposure to oil, water, organic fiuids, or any other liquid encountered in its use. Fluid resistance tests do not necessarily correlate with service performance, because service conditions are not easily defined. However, they are useful for screening compounds, because they give comparative assessments of expected performance. 

The largest volume of hydrauHc fluids are mineral oils containing additives to meet specific requirements. These fluids comprise over 80% of the world demand (ca 3.6 x 10 L (944 x 10 gal))- In contrast world demand for fire-resistant fluids is only about 5% of the total industrial fluid market. Fire-resistant fluids are classified as high water-base fluids, water-in-oil emulsions, glycols, and phosphate esters. Polyolesters having shear-stable mist suppressant also meet some fire-resistant tests. 

ISO 1167, Thermoplastics pipes for the conveyance of fluids - Resistance to internal pressure - Test method, 1996. 

Liquid transmission and permeation through hose and tube Corrosion testing for gaskets Fluid resistance of gasket materials... 

In such a device a motor-driven cylindrical cup is rotated at a constant speed. The fluid being tested is in the thin, annular region between the cup and the bob. The shear stress generated by the fluid on the wall of the bob tends to turn the bob, but this turning motion is resisted tiy the torsion wire which supports the bob. The bob takes up a position wherejthe torque exerted by the torsion wire is equal and opposite to the torque supplied by the fluid shear on its surface from its position, as indicated by a pointer and scale and the calibration of the torsion wire, one can readily compute the shear stress at the wall. 

The formers (and clamps) used must be completely resistant to the fluid being tested, and radii between 30 and 500 mm are found to give an adequate range of strains for most plastics over thicknesses from 2 to 4 mm. The preferred test temperatures are 23. 40, and 55 C. and the preferred durations are 22 to 24 hours for the short-term test and 1.000 hours for the long-term test, although other values may be used. A number of failure criteria are laid down in the standard to facilitate easy identification for specification purposes, and the table here illustrates these. 

Oil Resistance. This is a special case of fluid resistance. Elastomers may be swollen and weakened by oil. Standard petroleum-based ASTM test oils are used. 

ISO 4433 1984 Polyolefin pipes - Resistance to chemical fluids - Immersion test method -System for preliminary classification. 

Fig. 5.9. Test assembly and specimen for the stress crack resistance test based on the Bell test. The specimen that is slit in the middle has the dimensions 38 mm 13 mm thickness of the geomembrane. The test tube is stored at 50 °C (temperature of the test fluids) in a constant-temperature bath...

ISO 4433 [245] Polyolefin pipes Resistance to chemical fluids Immersion test method System for preliminary classification... 

However, many tests, particularly the fundamental property tests that are used to acquire physical data such as tensile strength, tear strength, oil and fluid resistance, and ageing performance are usually carried out on specially prepared test sheets due to the need for standard test pieces of a particular geometry. 

Fire-Resistant Hydraulic Fluids. Fire-resistant hydrauhc fluids are used where the fluid could spray or drip from a break or leak onto a source of ignition, eg, a pot of molten metal or a gas flame (17). Conditions such as these exist in die-casting machines or in presses located near furnaces. Specific tests for fire resistance are conducted by Factory Mutual in the United States. 

Diverse appHcations for the fabric sometimes demand specialized tests such as for moisture vapor, Hquid transport barrier to fluids, coefficient of friction, seam strength, resistance to sunlight, oxidation and burning, and/or comparative aesthetic properties. Most properties can be deterrnined using standardized test procedures which have been pubHshed as nonwoven standards by INDA (9). A comparison of typical physical properties for selected spunbonded products is shown in Table 2. 

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