Synthesis and characterization of novel polymer/clay nanocomposites based on poly (butylene 2,5-furan dicarboxylate)

In this work, polymer nanocomposites based on poly(butylene 2,5-furan dicarboxylate) (PBF) and clay nanoinclusions were synthesized via the in-situ transesterification and polycondensation method. PBF is a biobased alipharomatic polyester that is expected to replace its fossil-based terephthalate homologue, poly(butylene terephthalate) (PBT), while aluminosilicate clays have already been used as reinforcing fillers for commercial polymers. In this context, a series of PBF based nanocomposites with the nanoclays Cloisite (R)-Na (MMT), Cloisite (R)-20A (MMT 20A) and Cloisite (R)-10A (MMT 10A) were synthesized for the first time and the effect of the nanoclays on the properties of PBF were investigated with various techniques including Infrared Spectroscopy (FTIR), Nuclear Resonance Spectroscopy (H-1 NMR), Wide Angle X-ray Diffraction (WAXD), Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), Broadband Dielectric Spectroscopy (BDS) and nanoindentation tests. The crystallization rates of the polymers were accelerated by the insertion of the nanofillers, which were intercalated by the polymer chains to a different extend depending on the functionalization molecule on the interlayer surfaces. Furthermore, the addition of the clays improved the mechanical properties of the prepared polymers that were studied both in the amorphous and the semicrystalline state. Finally, broadband dielectric spectroscopy (BDS) was employed to study polymer dynamics, namely the local beta and segmental a relaxations, and construct the dielectric-calorimetric map. The most significant effects on molecular dynamics arose from the implementation of crystallization rather than by the fillers themselves.