Poly(3-hydroxybutyrate)/multi-walled carbon nanotubes nanocomposites: preparation and characterizations

In this study, the poly(3-hydroxybutyrate)/multi-walled carbon nanotubes (PHB/MWNTs) nanocomposite was prepared by means of a melt blending method. To improve the compatibility/dispersability of MWNTs within the PHB matrix, the acrylic acid grafted poly(3-hydroxybutyrate) (PHB-g-AA) and the multihydroxyl functionalized MWNTs (MWNTs-OH) were used as alternatives. Based on the results of TEM micrographs, FTIR spectra, C-13 solid-state NMR spectra, XRD patterns, and thermal and mechanical characterizations, the PHB-g-AA/MWNTs-OH blend demonstrated dramatic enhancement in thermal and mechanical properties of PHB due to the formation of ester carbonyl groups through the reaction between carboxylic acid groups of PHB-g-AA and hydroxyl groups of MWNTs-OH. For example, with an addition of 1 wt.% MWNTs-OH, the increases in the initial decomposition temperature and the tensile strength at break were 75 degrees C and 15.1 MPa, respectively. Finally, the optimal amount of MWNTs-OH was 1 wt.% because excess MWNTs-OH caused separation of the organic and inorganic phases and reduced their compatibility.