Differentialthermoanalytische untersuchungen bei verschiedenen drücken an einer molekulargewichtsreihe von polyethylenoxiden

✍ Scribed by Altmeyer, Andreas ;Karl, Veit-Holger ;Ueberreiter, Kurt

• Publisher: Wiley (John Wiley & Sons)
• Year: 1981
• Weight: 595 KB
• Volume: 182
• Category: Article
• ISSN: 0025-116X
• DOI: 10.1002/macp.1981.021821134

✦ Synopsis

Abstract

Melt‐ and crystallization‐temperatures were measured of poly(ethylene oxide)s with increasing molecular weight and at various pressures up to 5 000 bar by differential thermal analysis (DTA). Both these temperatures increase with pressure and display a different molecular weight dependence below and above M ≈ 3 000. A similar behaviour is shown by the melt enthalpies, constants a and c of the Simon‐equation and by the undercooling Δ__T__.

The transition from a zig‐zag‐ to a helix‐structure found by various authors changes to higher molecular weights with pressure, whereas chain folding does not depend upon pressure. The pressure coefficient of the melting temperature and the undercooling as well as the chemical potential are investigated as functions of the molecular weight for poly(ethylene oxide).