Evidence of Nanostructure Development from the Molecular Dynamics of Poly(pentamethylene 2,5- Furanoate)

Abstract

<div><div><div><p>We report on the molecular origin of poly(pentamethylene 2,5-furanoate) particular physical properties. From the structural point of view we found this polymer can develop crystallinity when stored at room conditions for months. On the other hand, we used broadband dielectric spectroscopy (BDS) measurements, to analyze in very detail the local and segmental molecular dynamics of the material subjected to several thermal treatments. In this way we evidenced that the molecular dynamics are sensitive to thermal history over a broad temperature range. This behavior has been attributed to possible inter-chain interactions detected via infrared spectroscopy and rheology measurements in the non-crystallized polymer.</p></div></div></div>

Poly(alkylene 2,5-Furanoate)s Thin Films: Morphology, Crystallinity and Nanomechanical Properties

“…Besides, the structural development seems to be completed nearly after 6 months, presenting the 6 months-and 1 year-aged films practically the same features. The slow crystallization kinetics in the PPeF thin films are in line with bulk calorimetric studies on this polymer [40]. In fact, in the present case we observed nanostructures resembling those of the non-symmetrical spherulites typically developed by polymers at low undercooling degree.…”

“…Then, the PPeF thin film presented a high mechanical stability even though in the rubbery state and in a confined geometry. This finding is in line with the interesting bulk properties of furanbased polymers, particularly those observed for PPeF in recent works [9,11,40]. In fact, Martínez-Tong and collaborators showed that this polymer does not reach Newtonian flow at high temperatures (120 -150 ºC), as observed by rheology measurements [40].…”

“…This finding is in line with the interesting bulk properties of furanbased polymers, particularly those observed for PPeF in recent works [9,11,40]. In fact, Martínez-Tong and collaborators showed that this polymer does not reach Newtonian flow at high temperatures (120 -150 ºC), as observed by rheology measurements [40]. Other authors have proposed the existence of interchain interactions in different furan-based polymers [11,59].…”

“…This behavior allows tuning the development of crystalline structures on PBF samples by playing with thermal treatments, as presented in the present manuscript. Finally, the PPeF sample, being the only one with a C-odd-numbered glycolic subunit, does not crystallize in "regular" laboratory times [9,11,40]. Concerning the glass transition temperature (𝑇 g ), according to recent studies, there is a decrease in 𝑇 g as the length of the alkyl chain increases [11,38].…”

“…Using this approach, we calculated a 𝜒 c = 0.28 (∆𝐻 m 0 = 143 J/g, [60]) for PHF, and 𝜒 c = 0.29 (∆𝐻 m 0 = 129 J/g, [61]) for PBF. In the case PPeF, there are not any reports on its value of ∆𝐻 m 0 , complicating the calculation of 𝜒 c by DSC, as thoroughly discussed in Ref [40]. However, considering its lower ∆𝐻 m value (Table 1) in combination with the AFM images (Figure 2), PPeF presents a low crystallizing ability, which might turn into a lesser and less perfect crystalline phase, i.e., much lower 𝜒 c and 𝑇 m as compared to PHF and PBF [40].…”