Structure-Property Relationships of Hyperbranched Polymer/Kaolinite Nanocomposites

Two methods were employed to prepare hyperbranched polyamine ester (HPAE)/kaolinite (Ka) nanocomposites resulting in different morphologies. In the case of the in situ polymerization, diethanolamine is inserted as monomer between the Ka layers and polymerized with methyl acrylate to prepare HPAE/Ka-DEA nanocomposites. For the ex situ method, Ka is modified with dodecylamine and solution-blended with HPAE. The former method leads to an intercalated morphology where the latter approach results in an exfoliated structure, as proofed by SAXS and TEM. A complementary combination of methods like differential scanning calorimetry (DSC), broadband dielectric relaxation (BDS), and specific heat spectroscopy (SHS) was used to investigate both kinds of nanocomposites in detail. Above T-g, the dielectric spectra are dominated by the conductivity contribution while the segmental dynamics is retrieved by SHS. A comparison of the temperature dependencies reveals a decoupling of segmental dynamics and conductivity, which becomes weaker with decreasing fragility.