Effect of Monomer Type on the Synthesis and Properties of Poly(Ethylene Furanoate)

Abstract

This work aimed to produce bio-based poly(ethylene furanoate) (PEF) with a high molecular weight using 2,5-furan dicarboxylic acid (FDCA) or its derivative dimethyl 2,5-furan dicarboxylate (DMFD), targeting food packaging applications. The effect of monomer type, molar ratios, catalyst, polycondensation time, and temperature on synthesized samples’ intrinsic viscosities and color intensity was evaluated. It was found that FDCA is more effective than DMFD in producing PEF with higher molecular weight. A sum of complementary techniques was employed to study the structure–properties relationships of the prepared PEF samples, both in amorphous and semicrystalline states. The amorphous samples exhibited an increase in glass transition temperature of 82–87 °C, and annealed samples displayed a decrease in crystallinity with increasing intrinsic viscosity, as analyzed by differential scanning calorimetry and X-ray diffraction. Dielectric spectroscopy showed moderate local and segmental dynamics and high ionic conductivity for the 2,5-FDCA-based samples. The spherulite size and nuclei density of samples improved with increased melt crystallization and viscosity, respectively. The hydrophilicity and oxygen permeability of the samples were reduced with increased rigidity and molecular weight. The nanoindentation test showed that the hardness and elastic modulus of amorphous and annealed samples is higher at low viscosities due to high intermolecular interactions and degree of crystallinity.

Fabrication of Poly(ethylene furanoate)/Silver and Titanium Dioxide Nanocomposites with Improved Thermal and Antimicrobial Properties

“…PEF synthesized from FDCA is brighter due to the monomer's high purity, as shown in Figure 1a. Also, the Sb 2 O 3 catalyst used in the polycondensation step shows high activity and helps to produce polyester with low coloration [28]. The neat PEF displayed higher L* and lower K/S values, indicating that films are brighter and have low color concentration.…”

“…1727 cm −1 were linked to C-O stretching vibration, 1575-1581 cm −1 corresponds to aromatic C-C bending vibration, 1507-1512 cm −1 and 1451-1460 cm −1 were linked to C-H deformation and wagging vibrations, 1372-1384 cm −1 were related to C-H rocking vibrations, 1263-1267 cm −1 and 1222-1229 cm −1 were linked to C-O stretching vibrations, 1105-1114 cm −1 and 1009-1020 cm −1 were related to C-O-C vibrations of furan ring, 944-953 cm −1 , 812-827 cm −1 and 760-766 cm −1 were linked to C-H out-of-plane deformation vibrations of furan ring, and 612-623 cm −1 corresponds to C-H bending vibrations [9,28]. Among the nanocomposites, PEF-TiO2 samples show tiny, sharp peaks around 3644-3708 cm −1 , indicating O-H stretching vibrations, as seen in Figure 3.…”