Polyethylene maximum operating temperatures

The maximum temperatures permissible for homopolymers in a number of diluents are listed in Table 75. These temperatures were determined in two ways, first, by laboratory swelling tests of a homopolymer in the particular hydrocarbon and, second, by actual experience in the production of homopolymers with the hydrocarbons in a pilot slurry reactor. Also shown in Table 75 is the degree of branching of each hydrocarbon, which is defined as the ratio of the number of methyl carbon atoms to the total number of carbon atoms. The swelling temperature correlates nicely with this ratio. Isobutane was chosen for commercial use as the best compromise between being highly branched and not too expensive. It permits a maximum operating temperature of about 111 °C for polyethylene homopolymer. 

Styrofoam (Dow Chemical Co.) is the tradename for expanded polystyrene foam. It is made by a process similar to the one described for foamed polyethylene. The materials have a closed-cell structure with very low thermal conductivity and low moisture absorption. One of the serious limitations of polystyrene foam is its rather low maximum operating temperature of approximately SO C. It is used mainly as thermal insulation in buildings, flotation apparatus, decorations, and packaging. 

In order to connect one of its wells to its facility in the Badin distriet of Pakistan, British Petroleum Pakistan planned to constmct 5000 ft (1524 m) of 4-inch diameter spoolable reinforced composite pipe (SRCP). Python series 1500 cross-linked polyethylene (PEX) spoolable pipe was seleeted, offering a maximum operating temperature of 180°F (80°C). Table 18.3 reports the physical properties of the spoolable reinforced composite pipe. 

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