Structure and Dynamics of Bio-Based Polymers in the Bulk and under Confinement

The structure and the dynamics of two bio-based polyester polyols are investigated in the bulk and close to surfaces when the polymers are intercalated within the galleries of a hydrophilic sodium montmorillonite, Na⁺-MMT. The morphology of the neat polymers as well as the structure of the nanohybrids are investigated with X-ray diffraction and their thermal properties are studied by differential scanning calorimetry. One of the investigated polyesters is amorphous whereas the second one is a semi-crystalline polymer with an intriguing thermal behavior. Hybrids have been synthesized in a broad range of compositions and intercalated structures are always obtained. Dielectric relaxation spectroscopy was utilized to study the polymer dynamics. It revealed multiple relaxation processes for the neat polymers both below and above their glass transition temperatures whereas, in the nanocomposites, similarities and differences are observed depending on the specific mode of dynamic process. The results are compared with the ones of hyperbranched polymers of similar chemistry but non-linear architecture. This research has been co-financed by the Greek General Secretariat for Research and Technology (Action: Roadmap of Research Infrastructures, project INNOVATION EL, MIS: 5002772).