A VSE equation of state for liquids. V. Poly(tetrafluoroethylene), 600–725 K

Abstract

SynopsisOur volume-entropy-energy ( V S E ) equation of state for liquids, first proposed in 1973 for use with low molecular weight homogeneous liquids, is here applied for the first time to a high molecular weight liquid that is heterogeneous in molecular weight, namely, a molten polymer. Four thermodynamic quantities, T, s, cp, and c, are calculated over the range of 600-725 K a t ambient pressure and are compared with experimental values, with excellent results. The grand average, of the standard percentage errors (S.P.E.) for the 24 points is 0.1100%.

Critical appraisal of the volume‐entropy‐energy equation for liquids

“…All of these results are summarized in The liquids studied were 5 n -alkanes? b e n~e n e ,~ m e r~u r y ,~ water,4 odium,^ poly(tetrafluoroethy1ene) , 6 and polymethylene of 75,000 molecular eight.^ Three sets of calculations were made on n-heptane. The firsts involved the exact equation for f 3 , but carried some of the calculations only as high as y obtained from literature values of PT, which was 372 K. The second set of calcul a t i o n~~ carried the results from Tmp to the highest experimental value of y obtained from internal pressure data, which was 390 K. The third set of calculat i o n~~ were carried from T u d to Tcrit, using values of y obtained from very accurate PVT data,1° which went to 540 K.…”