Free Volumes and Grüneisen Parameters in Mixed‐Tacticity Polyhydroxybutyrates

Abstract

Recently, nonlinear progressions of mechanical and thermal properties of mixed‐tacticity polyhydroxybutyrates have been discovered with their fraction of meso diads fmeso. Characteristic fmeso is traced by a measure trueλ̂ of polymer chain segment length disturbance, due to the inclusion of S enantiomers in chains consisting otherwise of R monomers. In this article, the material compositions' thermal expansion coefficients are reported on as determined by X‐ray diffraction and connect the qualitative trueλ̂ to their free volume fractions. Further, it is demonstrate that the previously determined Einstein oscillator modes correlate to Grüneisen parameters determined for a range of mixed‐tacticity polyhydroxybutyrates.