Upper plastic limit

Suspension films separating two solid surfaces, and Wetting films separating a solid or liquid from a vapour. The minimum water content for which a small sample of soil or similar material will barely flow in a standardized test method. Also termed the upper plastic limit . See also Atterberg Limits, Plastic Limit, Plasticity Number. Light non-aqueous phase liquid. See Non-aqueous Phase Liquid. 

P= (Upper plastic limit)—(Lower plastic limit). 

The sensitivity of the plastic properties upon concentration have even induced Atterberg to introduce certain specified concentrations as a measure of the plasticity of clays. A clay is characterized by its plastic number, which is the diflFerence between the "dipper and " lower plastic limits . The upper plastic limit is the moisture content at which the yield stress just becomes measurable. At the moisture content corresponding to the lower plastic limit, the yield stress is so high that the day has lost its plastic deformability. 

One would expect the upper plastic limit to be close to the concentration of a free sediment of the clay, because the sedimentation does not proceed further than the point at which the sediment acquires a certain solidity,... 

Maximum Service Temperature. Because the cellular materials, like their parent polymers (204), gradually decrease in modulus as the temperature rises rather than undergoing a sharp change in properties, it is difficult to precisely define the maximum service temperature of cellular polymers. The upper temperature limit of use for most cellular polymers is governed predominantly by the plastic phase. Fabrication of the polymer into a... 

Plastic Pipe In contrast to other piping materials, plastic pipe is free from internal and external corrosion, is easily cut and joined, and does not cause galvanic corrosion when coupled to other materials. Allowable stresses and upper temperature limits are low. Normal operation is in the creep range. Fluids for which a plastic is not suited penetrate and soften it rather than dissolve surface layers. Coefficients... 

If a motor car has to be refinished after repair, commonsense suggests that the original finishing system would be ideal for maintenance of protection and durability. However, with tyres, upholstery, fabric and plastic trim fitted and petrol in the tank, the use of such high stoving temperatures is not practical. The practical upper temperature limit is 80°C. This means that none of the original materials is suitable, not even the acrylic lacquer, since this is designed to be sanded and the scratches reflowed at 155 C. 

There can also be a flammability limit associated with dust clouds. The flammability limits of combustible dusts are reported as the minimum explosion concentrations. The upper explosion limits for dust clouds have not been determined due to experimental difficulties. In the fourteenth edition of the Fire Protection Handbook [National Fire Protection Association (NFPA), Boston, MA, 1975], numerous results from the U.S. Bureau of Mines reports are listed. These results were obtained with dusts 74 fim or smaller. It should be noted that variations in minimum explosive concentrations will occur with change in particle diameter, i.e., the minimum explosive concentration is lowered as the diameter of the particle decreases. Other conditions which affect this limit are sample purity, oxygen concentration, strength of ignition source, turbulence, and uniformity of the dispersion. The NFPA tabulation is most extensive and includes data for dusts from agricultural materials, carbonaceous matter, chemicals, drugs, dyes, metals, pesticides, and various plastic resins and molding compounds. Except for metal... 

Tl is is a yellow -brown coloured substance decomposing rapidly just below the (350°O but it has excellent thermal stability in the range 2W tWhich represents the upper teniperatiirc limit at which it may be used. The lecular structure of TATB was examined by X-ray analysis 44). TATB sses also a low sensitivity. However, the cv>mprcssed or plastic bonded terial tends to expand considerably. Subscquetitly Kolb and (451... 

Recommendations of upper temperature limits for plastics are usually based on general experience, although some consideration is given to high-load and low-load heat-distortion temperatures. The size and shape of the part as well as its molding... 

Fine grinding also offers solutions for the recycling of plastic scrap. Different types of machines are used, two common types being universal blast mills and disc pulverizers. In a universal blast mill, plastic scarp is reduced between the beater wings of a blast disc and a screen or the grooved grinding track of a grinding chamber. The hole size of the screen determines the fineness of the plastic powder. This usually has an upper size limitation of 500-800 nm. 

The glass transition temperature corresponds to the upper temperature limit of heat resistance of plastics. The lower hmit of thermal performance is a brittleness temperature (a temperature at which polymers can be fractured even at small deformations). This lower limit of performance temperature is about 10-170°C below the glass transition temperature. It depends on the type of polymer, its strength properties, and plasticizer type and content. 

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