Rubber lining working temperature

Sodium hydroxide from the decomposer usually has a concentration of 50 % and a temperature of 80 -120 °C. It passes through rubber-lined steel pipe work to nickel or Incoloy coolers, where it is cooled to 40-SOT. Any particles of graphite from the decomposer or traces of mercury are effectively removed by centrifuges, candle filters, or precoated leaf filters (Fig. 29). 

Wet chlorine is very corrosive to all of the more common construction metals. At low pressures wet chlorine can be handled in chemical stoneware, glass or porcelain equipment and in certain alloys. Hard rubber, polyvinyl chloride (maximum of 41 kPa (6 psig)), fiberglass-reinforced polyester, polyvinylidene chloride or fluoride and frilly halogenated fluorocarbon resins have been used successfully. For maximum working pressure see Chlorine Pamphlet 6 [9]. All of these materials must be selected with care. For higher pressures, lined metallic or compatible metallic systems should be used. In the metallic systems, Hastelloy C, titanium and tantalum have been used. Within limits, titanium may be used with wet chlorine, but must not be used with dry chlorine under any circumstances because it bums spontaneously on contact. Tantalum is inert to wet and dry chlorine at temperatures up to 300°F(149°C). 

Walters reached a similar conclusion from his experimental results. He obtained the friction-temperature relations at constant sliding speed. The temperature of maximum friction at a constant speed, increases linearly with the glass transition temperature. It appeared however, that in a graphical plot of the linear relation the point corresponding to the results obtained with butyl rubber falls distinctly outside the line. In our work with butyl rubber such an anomalous behaviour has been confirmed. Instead of relating the speed of maximum friction to Tg, Grosch related it to the frequency at which the loss modulus is a maximum. That correlation has been found to be valid to several rubbers includ ing butyl rubber. On the other hand, it is not surprising to expect that besides Tg, there are other parameters which have an important influence upon friction properties. 

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