Pressure‐specific volume‐temperature behavior of thermoplastics under normal processing conditions

Abstract

Abstract In the processing of thermoplastics, the economy of the process and the quality of moldings are decisively influenced by material thermal properties. Therefore, it is particularly important for the processor to know and consider such properties. Process analyses have revealed that the processing conditions can be set to achieve optimum results by the application of pressure‐volume‐temperature diagrams, particularly if used in conjunction with computer control of the process. A new measuring instrument is described which makes it possible to determine such diagrams under normal processing conditions, that is, at normal cooling rates and pressures. The results contrast with values heretofore quoted in the literature, where values have been measured at very slow heating and cooling rates. Some experimental results and their practical use are discussed.