Shrinkage elevated

The sliced sheet will still contain large quantities of alcohol and it is necessary to season the sheet at elevated temperatures. This may only take three days at 49°C for 0.010 in (0.025 cm) thick sheet but will take about 56 days for 1 in (2.5 cm) thick blocks. The removal of alcohol, as might be expected, is accompanied by considerable shrinkage. Fully seasoned sheet has a volatile content of 2%, the bulk of which is water but there is some residual alcohol. The sheet may be fully polished by heating in a press between glazed plates under pressure for a few minutes. Because the material is thermoplastic it is necessary to cool it before removal from the press. 

Other areas of application include a number of plastics which are processed at elevated temperature. P.R.209 lends color to polyolefins (in which it only slightly affects the shrinkage), to ABS, to polyacetal resins, and other industrial polymers. 

The petroleum engineer needs to be able to estimate the density of the reservoir liquid at reservoir conditions. Then the shrinkage in volume that a reservoir liquid undergoes while progressing from the reservoir to the stock tank can be estimated. There are several methods of calculating the volume occupied by a given mass of liquid at elevated pressures and temperatures. We will consider only one method the method most applicable to the liquids encountered in the oil fields. This. method is based on ideal-solution principles. 

ASTM D1299, Test Method for Shrinkage ofMolded and Laminated Thermosetting Plastics at Elevated Temperatures, Vol. 8.01, ASTM, Philadelphia, Pa., 1979. 

Figure 13.13 shows such a distribution measured by Menges and Wiibken (30) for amorphous PS. They measured the shrinkage of microtomed molded samples at elevated temperatures. Figure 13.13(a) shows the longitudinal (flow direction) orientation distribution at two injection rates. The characteristic features of the orientation distribution are a maximum orientation at the wall that vanishes at the center with a local maximum near the wall. In Fig. 13.13(b), the longitudinal orientation at the wall and secondary maximum orientation are in close proximity, and the transverse orientation drops continuously from a maximum value at the surface. 

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