Study of the Crystal Structure and Hydrogen Bonding during Cold Crystallization of Poly(trimethylene 2,5-furandicarboxylate)

Abstract

Here, we present a detailed description of the in situ isothermal crystallization of poly(trimethylene 2,5-furandicarboxylate)(PTF) as revealed by realtime Fourier transform infrared spectroscopy (FTIR) and grazing incidence wideangle X-ray scattering (GIWAXS). From FTIR experiments, the evolution of hydrogen bonding with crystallization time can be monitored in real time, while from GIWAXS, crystal formation can be followed. Density functional theory (DFT) calculations have been used to simulate FTIR spectra for different theoretical structures, enabling a precise band assignment. In addition, based on DFT ab initio calculations, the influence of hydrogen bonding on the evolution with crystallization time can be understood. Moreover, from DFT calculations and comparison with both FTIR and GIWAXS experiments, a crystalline structure of poly(trimethylene 2,5furandicarboxylate) is proposed. Our results demonstrate that hydrogen bonding is present in both the crystalline and the amorphous phases and its rearrangement can be considered as a significant driving force for crystallization of poly(alkylene 2,5-furanoate)s.

Insights into Conformation, Crystal Structure, and Material Properties of Plant-Derived Poly(alkylene 2,5-furandicarboxylate)s as Sustainable Alternatives to Petroleum-Derived Analogues

“…As for the spacer conformation, prior studies suggested that the central C–C bond of PEF adopts a gauche conformation. , Furthermore, an infrared study estimated its trans fraction to be around 10% . DFT calculations using the vdW-DF-cx functional on a single PTF chain suggested that the tggt conformation is the most stable . A DFT study on PBF at the B3LYP/6-311­(d,p) level reported the tgtgt conformation to be the most energetically favorable for the spacer .…”