Characterization of bionanocomposites based on medium chain length polyhydroxyalkanoates synthesized by Pseudomonas oleovorans

Medium chain length polyhydroxyalkanoates (mcl-PHA) have been produced by fed-batch cultivation of Pseudomonas oleovorans. Using octanoic acid as the sole carbon substrate, a copolymer of 3-hydroxyoctanoate and 3-hydroxyhexanoate monomer units was accumulated up to 38 wt. % of cell mass. Mcl-PHA based nanocomposites have then been prepared using Cloisite 15A as nanofiller and characterized. Wide angle X-ray diffraction and rheological analysis of the nanocomposites highlighted their morphologies, which can be considered as well-intercalated structures. The thermal characteristics of mcl-PHA are not significantly affected by the nanofiller incorporation. On the contrary, the storage moduli of nanocomposites are greatly enhanced with increasing clay fraction due to the degree of dispersion of the nanoplatelets in the polymer matrix.