Calorimetric and Dielectric Study of Renewable Poly(hexylene 2,5-furan-dicarboxylate)-Based Nanocomposites In Situ Filled with Small Amounts of Graphene Platelets and Silica Nanoparticles

Abstract

Poly(hexylene 2,5 furan-dicarboxylate) (PHF) is a relatively new biobased polyester prepared from renewable resources, which is targeted for use in food packaging applications, owing to its great mechanical and gas barrier performance. Since both properties are strongly connected to crystallinity, the latter is enhanced here by the in situ introduction in PHF of graphene nanoplatelets and fumed silica nanoparticles, as well as mixtures of both, at low amounts. For this investigation, we employed Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and dielectric spectroscopy (BDS). The fillers were found to improve crystallization in both the rate (increasing Tc) and fraction (CF), which was rationalized via the concept of fillers acting as crystallization agents. This action was found stronger in the case of graphene as compared to silica. BDS allowed the detection of local and segmental dynamics, in particular in PHF for the first time. The glass transition dynamics in both BDS (α relaxation) and DSC (Tg) are mainly dominated by the relatively high CF, whereas in the PHF filled uniquely with silica strong spatial confinement effects due to crystals were revealed. Finally, all samples demonstrated the segmental-like dynamics above Tg, which screens the global chain dynamics (normal mode).

Molecular mobility and crystallization of renewable poly(ethylene furanoate) in situ filled with carbon nanotubes and graphene nanoparticles

“…[poly(butylene furanoate) (PBF) and poly(hexylene furanoate) (PHF)] 4,16,18 . In principle the 4 polycondensation methods result in low molar mass PnAFs, which is the reason that in many cases PnAFs do not easily crystallize during cooling from the melt state, whereas they demonstrate quite strong cold crystallization during heating 5,19 .…”

“…In our recent works 18,31,38,39 , we have demonstrated the potential for tuning the crystallizability of three furan based polyesters, namely, PPF, PBF and PHF, by reinforcing the polymer via the in situ introduction to the PnAF matrix of low amounts of various types nanoparticles acting as nucleating agents. The nanoparticles consisted of montmorillonite clays 40,41 , graphene nanoplatelets (GNP) and graphene oxide (GO) 42 , carbon nanotubes (CNT) 43 , halloysite nanotubes or spherical nanosilicas 44 .…”

Promoting Interfacial Interactions with the Addition of Lignin in Poly(Lactic Acid) Hybrid Nanocomposites

“…One may assume that the kinetic fragility increases, along with cooperativity, by adding lignin to PLLA nanocomposites, due to the increase of the volume term; however, further investigations are needed to validate this assumption. Indeed, various trends can be found in the literature regarding fragility variations with nanofiller inclusion [ 24 , 50 , 57 , 58 , 59 ], and it has been shown that cooperativity and fragility can evolve in opposition [ 60 ].…”

Mechanical and Functional Properties of Novel Biobased Poly(decylene-2,5-furanoate)/Carbon Nanotubes Nanocomposite Films

“…This is partly mitigated in FDCA-based polyesters with longer alkyl chains, as the higher molecular mobility helps the local ordered arrangement of the polymer chains, thereby favoring the obtainment of a relevant crystallinity degree [ 17 ]. This is desirable for the final applications, as a higher crystallinity degree is generally associated with a higher gas-barrier performance [ 22 ]. Moreover, an increased number of carbon atoms in the monomer diol leads to mitigation of the thermo-mechanical properties, i.e., a decrease in the elastic modulus, glass transition temperature, and melting temperature and an increase in flexibility.…”

“…The existing studies mainly focus on the addition of carbon-based nanofillers and nanoclays in PEF [ 15 , 26 , 27 , 28 , 29 , 30 ], but some research also deals with PBF [ 31 ], poly(propylene furanoate) (PPF) [ 32 , 33 ], or poly(hexamethylene furanoate) (PHF) [ 22 ], mainly prepared by in-situ polymerization in presence of a nanofiller suspension. In these cases, nanofillers are added to increase the mechanical properties but especially the crystallization kinetics and the gas barrier performance [ 22 ]. Conversely, to the best of the authors’ knowledge, no research can be found on the development of nanocomposites with FDCA-based polymers with longer alkyl chains.…”