Melting content

Permanent irreversible deformation takes place at high temperatures as a result of mechanical stressing, e.g. above 1000 °C for fireclay. This is mostly due to the presence of a melt which at this stage has a viscosity of about 10 dPa s. The temperature of softening and permanent deformation depends on the amount and viscosity of the melt. At the same melt content, the perceptible onset of softening is shifted towards higher temperatures, the higher the melt viscosity. 

Cellulose ester Viscosity, Pa-s Acetyl content, wt% Butyryl Propionyl Hydroxyl Melting content, content, content, range, wt% wt% wt% C M, "C Den- sity, g/cm ... 

Figure 7.2.1 shows the temperature dependence of the electrical conductivity for a (Lio.52Nao.4g)2C03 eutectic melt coexisting with Gd-doped ceria (GDC) for various melt contents in a CO2 flow. Around the eutectic point, an abrupt change of the electrical conductivity was caused by the melting of the eutectics. It is suggested that carbonates interact with the solid surface and a small amount of stable non-frozen liquid exists on the solid... 

Before this treatment, the cassiterite content of the ore is increased by removing impurities such as clay, by washing and by roasting which drives off oxides of arsenic and sulphur. The crude tin obtained is often contaminated with iron and other metals. It is, therefore, remelted on an inclined hearth the easily fusible tin melts away, leaving behind the less fusible impurities. The molten tin is finally stirred to bring it into intimate contact with air. Any remaining metal impurities are thereby oxidised to form a scum tin dross ) on the surface and this can be skimmed off Very pure tin can be obtained by zone refining. 

Succinamide. NHoCOCH2 CH2CONH2. (Method 2(a)). Add 5 ml. (5 8 g.) of dimethyl succinate to a mixture of 50 ml. of water and 25 ml. of concentrated [dy o-88o) aqueous ammonia solution in a 150 ml. conical flask. Cork the flask and shake the contents the dimethyl succinate rapidly dissolves to give a clear solution. Allow the solution to stand after about i hour the succinamide starts to crystallise, and then continues to separate for some time. Next day, filter off the succinamide at the pump, wash with cold water, and drain. Recrystallise from water, from which the succinamide separates as colourless crystals the latter soften at 240° and melt at 254 -255° with... 

Succinamide. Add 5 g. (4-8 ml.) of dimethyl succinate to 25 ml. of concentrated ammonia solution (sp. gr. 0-88) in a 100 ml. conical flask. Cork the flask and shake the contents for a few minutes aUow to stand for 24 hours with occasional shaking. Filter off the crystals of succinamide, and wash with a Uttle cold water. RecrystaUise from a little hot water. Dry in the steam oven and determine the m.p. The yield is 3-5 g. Pure succinamide melts at 254° with decomposition. 

The apparatus required is similar to that described for Diphenylmelhane (Section IV,4). Place a mixture of 200 g. (230 ml.) of dry benzene and 40 g. (26 ml.) of dry chloroform (1) in the flask, and add 35 g. of anhydrous aluminium chloride in portions of about 6 g. at intervals of 5 minutes with constant shaking. The reaction sets in upon the addition of the aluminium chloride and the liquid boils with the evolution of hydrogen chloride. Complete the reaction by refluxing for 30 minutes on a water bath. When cold, pour the contents of the flask very cautiously on to 250 g. of crushed ice and 10 ml. of concentrated hydrochloric acid. Separate the upper benzene layer, dry it with anhydrous calcium chloride or magnesium sulphate, and remove the benzene in a 100 ml. Claisen flask (see Fig. II, 13, 4) at atmospheric pressure. Distil the remaining oil under reduced pressure use the apparatus shown in Fig. 11,19, 1, and collect the fraction b.p. 190-215°/10 mm. separately. This is crude triphenylmethane and solidifies on cooling. Recrystallise it from about four times its weight of ethyl alcohol (2) the triphenylmethane separates in needles and melts at 92°. The yield is 30 g. 

Cautiously add 250 g. (136 ml.) of concentrated sulphuric acid in a thin stream and with stirring to 400 ml. of water contained in a 1 litre bolt-head or three-necked flask, and then dissolve 150 g. of sodium nitrate in the diluted acid. Cool in a bath of ice or iced water. Melt 94 g. of phenol with 20 ml. of water, and add this from a separatory funnel to the stirred mixture in the flask at such a rate that the temperature does not rise above 20°. Continue the stirring for a further 2 hours after all the phenol has been added. Pour oflF the mother liquid from the resinous mixture of nitro compounds. Melt the residue with 500 ml. of water, shake and allow the contents of the flask to settle. Pour oflF the wash liquor and repeat the washing at least two or three times to ensure the complete removal of any residual acid. Steam distil the mixture (Fig. II, 40, 1 or Fig. II, 41, 1) until no more o-nitrophenol passes over if the latter tends to solidify in the condenser, turn oflF the cooling water temporarily. Collect the distillate in cold water, filter at the pump, and drain thoroughly. Dry upon filter paper in the air. The yield of o-nitrophenol, m.p. 46° (1), is 50 g. 

Method 2. Intimately mix 99 g. of pure phthahc anhydride and 20 g. of urea, and place the mixture in a 1 litre long-necked, round-bottomed flask. Heat the flask in an oil bath at 130-135°, When the contents have melted, eflfervescence commences and graduaUy increases in vigour after 10-20 minutes, the mixture suddenly froths up to about three times the original volume (this is accompanied by a rise in temperature to 150-160°) and becomes almost sohd. Remove the flame from beneath the bath and allow to cool. Add about 80 ml. of water to disintegrate the sohd in the flask. Alter at the pump, wash with a httle water, and then dry at 100°. The yield of phthahmide, m.p. 233° (i.e., it is practically pure) is 86 g. If desired, the phthahmide may be recrystalhsed from 1200 ml. of methj lated spirit the first crop consists of 34 g. of m.p. 234°, but further quantities may be recovered from the mother hquor. 

The properties of SAN resins depend on their acrylonittile content. Both melt viscosity and hardness increase with increasing acrylonittile level. Unnotched impact and flexural strengths depict dramatic maxima at ca 87.5 mol % (78 wt %) acrylonitrile (8). With increasing acrylonitrile content, copolymers show continuous improvements in barrier properties and chemical and uv resistance, but thermal stabiUty deteriorates (9). The glass-transition... 

This compound, designated Cyagard RF1204, has been recommended for use in polypropylene. Despite its high hydroxyl content, it is proposed not as a polyol but as a stable, high melting additive for polypropylene (108). 

This phosphinic anhydride [15171 -48-9] C H O P, is then reacted with glycol and other precursors of poly(ethylene terephthalate), to produce a flame-retardant polyester [82690-14-0] having phosphinate units of the stmcture —0P(0)(CH2)CH2CH2C00—. Trevira 271 is useflil for children s sleepwear, work clothing, and home flirnishings. A phosphoms content as low as 0.6% is reported to be sufficient for draperies and upholstery tests if melt-drip is not retarded by print pigments or the presence of nonthermoplastic fibers (28). 

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