Thermodynamic properties of a series of semi-rigid polyesters

Abstract

The thermodynamic properties of a series of poly[oxy(2,2′ dialkylpropane-1,3-diyl) carboxybisphenyl- 4,4′-dicarbonyl] have been investigated by P-V-T-measurements as a function of the length of one side-chain at the 2′-position.

The pressure-and temperature dependence of the specific volume was recorded from room temperature to 300 °C and from ambient pressure to 200 MPa. Depending on the chemical constitution glass-transitions, enantiotropic and monotropic mesophase transitions were identified. A pressure-induced transition in the glass was observed in one case and unusual behaviour of the volume for a first order mesophase transition in another case.

Keywords:

• Semi-rigid polymers
• Transitions
• P-V-T dependence