Molecular dynamics of fully biobased poly(butylene 2,5-furanoate) as revealed by broadband dielectric spectroscopy

This work presents the molecular dynamics of both fully amorphous and semicrystalline poly(butylene 2,5-furanoate) (PBF). Broadband dielectric spectroscopy experiments were combined with temperature modulated differential scanning calorimetry measurements. The results showed that the subglass molecular dynamics is characterized by the existence of two dielectric relaxation processes, being the faster one associated to the glycolic subunit, whereas the slower relaxation was assigned to the link in between the ester group and the furan ring. Crystallization affected differently the contribution of these two components. Additionally, crystallization had a stronger effect on the α relaxation process, related to the segmental dynamics of the amorphous phase. In the semicrystalline state, the PBF amorphous phase was described as being composed by different fractions, including a completely rigid one, with distinctly slower mobilities and reduced contributions to the dielectric relaxation, compared to the fully amorphous polymer.