Marchessault_2011_Int.J.Biol.Macromol_48_271

Medium chainlength (mcl) polyhydroxyalkanoates (PHAs) are a class of polymers receiving attention because of their potential as renewable, biodegradable and high tech properties. Unlike most short chain PHAs, mcl-PHAs are low crystallinity and elastomeric in character. In this paper we wish to point out that in their broad properties mcl-PHAs might be classified as thermotropic liquid crystals with dynamic conformational disorder and long range orientational order. As the characterization of mcl-PHAs progresses, their similarities to liquid crystalline elastomers are noteworthy. Wunderlich coined the acronym CONDIS from the words "conformational disorder" to categorize this type of liquid crystal. Thermal analysis reveals a T(g) of -40 to -45 degreesC with several T(m) peaks. The chemistry of the elastomer from (13)C NMR confirms the poly(3-hydroxynonanoate), PHN, composition of the starting material along with two other samples containing double bonds: PHNU-18 and PHNU-31 where the numeral stands for the percent of double bonds.