Glass transition dynamics and cooperativity length of poly(ethylene 2,5-furandicarboxylate) compared to poly(ethylene terephthalate)

Abstract

The glass transition of poly(ethylene 2,5-furandicarboxylate) (PEF), an emergent bio-based polyester, was investigated in comparison to one of its chemical analogues: poly(ethylene terephthalate) (PET). These investigations were conducted at different crystallinities by means of stochastic modulated differential scanning calorimetry (stochastic TMDSC) and dynamic mechanical analysis (DMA). Amorphous PEF presents a higher ΔCp at the glass transition and a broader relaxation spectrum attributed to a higher free volume. The higher Tg of PEF is then purely related to segmental mobility and specific interactions in PEF. The length of cooperative rearranging regions (CRR) was similar for both materials. Additionally, the variations of the effective activation energy E of PEF and PET at glass transitions were determined by isoconversional kinetic analysis. The rate of decrease in E was similar for the two amorphous polyesters. Upon crystallization, the glass transition of PEF is broadened but its temperature range is not increased as with PET. The creation of the rigid amorphous fraction (RAF) with crystallinity is lower in PEF than in PET. The difference in free volume also explains the lower coupling between the crystalline phase and the amorphous phase in PEF.

Biaxial Orientation of Poly(ethylene 2,5‐furandicarboxylate): An Explorative Study

“…The variation of elastic modulus with temperature is presented in Figure (top) and the corresponding tan δ curves are shown in Figure (bottom). In Figure , the α‐relaxation of the amorphous phase of PEF samples is marked by a drop of the elastic modulus between 80 and 120 °C (approximately two decades), generally at higher temperatures for the oriented films (i.e., +12 °C) in comparison to the nonoriented specimens . For the PEF sample stretched until 4 × 4, the relaxation is followed by an increase of E′ around 130 °C, which was attributed to cold crystallization in agreement with the DSC curves.…”

“…Papageorgiou et al and various published work by their group have highlighted that FDCA‐based polyesters in general display reduced crystallization rates and melt points compared to their TPA‐ and 2,6‐Naphthalenedicarboxylic Acid (NDCA)‐based counterparts, while the glass transition temperatures typically fall in‐between . This is in line with the the finding of comparable glass transition dynamics of PEF and PET by Codou et al, which were explained by the chain mobility being counteracted by a higher free folume between the chains, resulting in among others a reduced T g increase by quiescent crystallization compared to PET …”

“…This can explain the particularly significant reduction in PEF shrinkage measured at 90 °C (Figure ). Furthermore, the T g values are 15–22 °C higher than those reported previously for nonoriented PEF . This highlights the important effect of chain orientation on the PEF relaxation behavior, considering that the relatively low amount of SIC found in oriented PEF is not impacting the mobility of amorphous chains.…”

Molecular Dynamics of Poly(ethylene‐2,5‐furanoate) (PEF) as a Function of the Degree of Crystallinity by Dielectric Spectroscopy and Calorimetry

“…[ 13,14 ] In view of this, subsequent studies reported on the thermal behavior, mechanical, and gas barrier properties. [15][16][17][18][19][20][21][22][23] Despite its importance for packaging, the molecular dynamics of PEF as a function of the degree of crystallinity has not been studied up to now. In the present study we employ different preparation protocols resulting in PEFs with distinctly different degrees of crystallinity and investigate the molecular dynamics by dielectric spectroscopy (DS) and the thermal behavior by differential scanning calorimetry (DSC).…”

Advances in polymer precursors and bio‐based polymers synthesized from 5‐hydroxymethylfurfural

“…In addition to the synthesis of FDCA‐based polyesters, their physical properties (i.e., crystallinity, thermal and mechanical properties, thermal degradation, structural properties and permeability) have been investigated as well. The thermal and barrier properties of polyethylene 2,5‐furandicarboxylate (PEF) were highly comparable to their analogue polyethylene terephthalate (PET) . More recently, catalytic production of FDCA from lignocellulosic biomass, and FDCA‐based polyesters and polyamides have been reviewed .…”