Stiffening reactive

Vulcanisation of rubber Natural rubber becomes soft at high temperature (>335 K) and brittle at low temperatures (<283 K) and shows high water absorption capacity, it Is soluble in non-polar solvents and Is non-resistant to attack by oxidising agents. To improve upon these physical properties, a process of vulcanisation is carried out. This process consists of heating a mixture of raw rubber with sulphur and an appropriate additive at a temperature range between 373 K to 415 K. On vulcanisation, sulphur forms cross links at the reactive sites of double bonds and thus the rubber gets stiffened. 

Since, platinum is too soft in pure condition, it is alloyed for stiffening, usually with a fraction of a per cent of irridium. The life of platinum utensils are maintained well by (a) keeping them chemically clean, (b) avoiding specific reagents in which platinum is soluble or reactive and (c) handling them so as to keep them in good mechanical condition. 

After the mix has set, the hydration of the less reactive fractions of the lime continues (as does the slower hydration of cement). This results in a progressive stiffening of the mix as well as a progressive rise in temperature. The latter increases the water vapour pressure within the hydrogen bubbles and if that pressure exceeds a critical level, it causes cracking within the cake, and loss of strength. 

The aliphatic side chains of valine, isoleucine, leucine and methionine have no reactive groups, only methylene, methyl (Me) and SMe groups. They are important, however, because they do not interact well with water, preferring each other. In addition, if they are branched as are isoleucine and valine, they stiffen the main chain and decrease its flexibility [30]. Phenylalanine is nonpolar like benzene or toluene. It has a methylene group which lengthens the side chain and prevents steric hindrance with the main chain. These are hydrophobic residues found in the center of proteins and provide a core around which the functional parts of the protein are assembled. The... 

HMIS Health 1, Flammability 1, Reactivity 0 Uses Perfumery surfactants lubricant for plastics processing resins antifoam food additive intermediate in mfg. of food additives surfactant, emulsion stabilizer, emulsifier, emollient, stiffener, astringent in pharmaceuticals cosolvent emulsifier, thickener, emollient, emulsion stabilizer, opacifier, vise, control agent in cosmetics in food-pkg. adhesives in food-contact coatings defoamer in food-contact coatings and paper/paperboard in cellophane for food pkg. food-contact textiles... 

Core support structure design with square grids at the central portion and radial stiffeners around the periphery has been recommended. Structural integrity assessment has demonstrated that even with the absence of the most critical radial stiffener, the reduction of rigidity of the structure is within the acceptable limits from reactivity insertion considerations. 

Water absorption by cement, especially if the latter has a high C3A content, furthermore causes retardation of setting (because of diminished reactivity of the C3A) and, depending on how much water is absorbed, also causes loss of strength (in consequence of pre-hydration of the C3S in the cement). Besides, false set - temporary early stiffening of the cement when mixed with water - may also be due to causes associated with silo storage (see Section V.3). 

Flame retardant additives are reactive, which means that they are less stable than the polymers they may decompose during normal processing and/or use. This limits the choice of additives that can be used, and it further limits the processing conditions that may be used. These additives are particulate fillers. Large amounts are needed to flame retard polyolefins they are difficult to disperse uniformly and they result in serious stiffening and even embrittlement, particularly in PP. 

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