Search Results (7)

Novel poly(butylene succinate-butylene furandicarboxylate/polyethylene glycol succinate) (PBSF-PEG) was synthesized using two-step transesterification and polycondensation in the melt. There are characterized by intrinsic viscosity, GPC, ¹H NMR, DSC, TGA, tensile, water absorption tests, and water degradation at different pH. GPC analysis showed that PBSF-PEG had high molecular weight with average molecular weight (M_w) up to 13.68 × 10⁴ g/mol. Tensile tests showed that these polymers possessed good mechanical properties with a tensile strength as high as 30 MPa and elongation at break reaching 1500%. It should be noted that the increase of PEG units improved the toughness of the polyester material. In addition, the introduction of PEG promoted the water degradation properties of PBSF, and the copolymer showed a significantly faster water degradation rate when the PEG unit content was 20%. This suggests that the amount of PEG introduced could be applied to regulate the water degradation rate of the copolymers. Hence, these new polymers have great potential for application as environmentally friendly and sustainable plastic packaging materials. Full article

Intending to expand the thermo-physical properties of bio-based polymers, furan-based thermoplastic polyesters were synthesized following the melt polycondensation method. The resulting polymers, namely, poly(ethylene 2,5-furandicarboxylate) (PEF), poly(propylene 2,5-furandicarboxylate) (PPF), poly(butylene 2,5-furandicarboxylate) (PBF) and poly(1,4-cyclohexanedimethylene 2,5-furandicarboxylate) (PCHDMF) are used in blends together with various polymers of industrial importance, including poly(ethylene terephthalate) (PET), poly(ethylene 2,6-naphthalate) (PEN), poly(L-lactic acid) (PLA) and polycarbonate (PC). The blends are studied concerning their miscibility, crystallization and solid-state characteristics by using wide-angle X-ray diffractometry (WAXD), differential scanning calorimetry (DSC) and polarized light microscopy (PLM). PEF blends show in general dual glass transitions in the DSC heating traces for the melt quenched samples. Only PPF–PEF blends show a single glass transition and a single melt phase in PLM. PPF forms immiscible blends except with PEF and PBF. PBF forms miscible blends with PCHDMF and PPF, whereas all other blends show dual glass transitions in DSC and phase separation in PLM. PCHDMF–PEF and PEN–PEF blends show two glass transition temperatures, but they shift to intermediate temperature values depending on the composition, indicating some partial miscibility of the polymer pairs. Full article

The enzymatic synthesis of polyesters in solventless systems is an environmentally friendly and sustainable method for synthetizing bio-derived materials. Despite the greenness of the technique, in most cases only short oligoesters are obtained, with limited practical applications or requiring further chemical processing for their elongation. In this work, we present a catalyst-free thermal upgrade of enzymatically synthesized oligoesters. Different aliphatic and aromatic oligoesters were synthesized using immobilized Candida antarctica lipase B (iCaLB) as the catalyst (70 °C, 24 h) yielding poly(1,4-butylene adipate) (PBA, M_w = 2200), poly(1,4-butylene isophthalate) (PBI, M_w = 1000), poly(1,4-butylene 2,5-furandicarboxylate) (PBF, M_w = 600), and poly(1,4-butylene 2,4-pyridinedicarboxylate) (PBP, M_w = 1000). These polyesters were successfully thermally treated to obtain an increase in M_w of 8.5, 2.6, 3.3, and 2.7 folds, respectively. This investigation focused on the most successful upgrade, poly(1,4-butylene adipate), then discussed the possible effect of di-ester monomers as compared to di-acids in the thermally driven polycondensation. The herein-described two-step synthesis method represents a practical and cost-effective way to synthesize higher-molecular-weight polymers without the use of toxic metal catalysts such as titanium(IV) tert-butoxide, tin(II) 2-ethylhexanoate, and in particular, antimony(IV) oxide. At the same time, the method allows for the extension of the number of reuses of the biocatalyst by preventing its exposure to extreme denaturating conditions. Full article

Poly(butylene 2,5-furandicarboxylate) (PBF) constitutes a new engineering polyester produced from renewable resources, as it is synthesized from 2,5-furandicarboxylic acid (2,5-FDCA) and 1,4-butanediol (1,4-BD), both formed from sugars coming from biomass. In this research, initially high-molecular-weight PBF was synthesized by applying the melt polycondensation method and using the dimethylester of FDCA as the monomer. Furthermore, five different series of PBF blends were prepared, namely poly(l-lactic acid)–poly(butylene 2,5-furandicarboxylate) (PLA–PBF), poly(ethylene terephthalate)–poly(butylene 2,5-furandicarboxylate) (PET–PBF), poly(propylene terephthalate)–poly(butylene 2,5-furandicarboxylate) (PPT–PBF), poly(butylene 2,6-naphthalenedicarboxylate)-poly(butylene 2,5-furandicarboxylate) (PBN–PBF), and polycarbonate–poly(butylene 2,5-furandicarboxylate) (PC–PBF), by dissolving the polyesters in a trifluoroacetic acid/chloroform mixture (1/4 v/v) followed by coprecipitation as a result of adding the solutions into excess of cold methanol. The wide-angle X-ray diffraction (WAXD) patterns of the as-prepared blends showed that mixtures of crystals of the blend components were formed, except for PC which did not crystallize. In general, a lower degree of crystallinity was observed at intermediate compositions. The differential scanning calorimetry (DSC) heating scans for the melt-quenched samples proved homogeneity in the case of PET–PBF blends. In the remaining cases, the blend components showed distinct T_gs. In PPT–PBF blends, there was a shift of the T_gs to intermediate values, showing some partial miscibility. Reactive blending proved to improve compatibility of the PBN–PBF blends. Full article

Poly(ether ester)s (PEEs) represent a promising class of segmented co-polymers, nevertheless the synthesis of PEEs based on renewable 2,5-furandicarboxylic acid (FDCA) is still scarce. In this context, a series of poly(1,4-butylene 2,5-furandicarboxylate)-co-poly(poly(propylene oxide) 2,5-furandicarboxylate) co-polyesters with different composition of stiff poly(1,4-butylene 2,5-furandicarboxylate) (PBF) and soft poly(poly(propylene oxide) 2,5-furandicarboxylate) (PPOF) moieties were synthesized, via a two-step bulk polytransesterification reaction. The molar ratio of PBF/PPOF incorporated was varied (10 to 50 mol%) in order to prepare several novel materials with tuned properties. The materials were characterised in detail through several techniques, namely ATR FTIR, ¹H and ¹³C NMR, TGA, DSC, DMTA and XRD. Their hydrolytic and enzymatic degradation evaluation was also assessed. These new co-polymers showed either a semi-crystalline nature when higher PBF/PPOF ratios were used, and for approximately equal amounts of PBF and PPOF an amorphous co-polyester was obtained instead. Full article

Polyesters made from 2,5-furandicarboxylic acid (FDCA) have been in the spotlight due to their renewable origins, together with the promising thermal, mechanical, and/or barrier properties. Following the same trend, (nano)composite materials based on FDCA could also generate similar interest, especially because novel materials with enhanced or refined properties could be obtained. This paper presents a case study on the use of furanoate-based polyesters and bacterial cellulose to prepare nanocomposites, namely acetylated bacterial cellulose/poly(butylene 2,5-furandicarboxylate) and acetylated bacterial cellulose/poly(butylene 2,5-furandicarboxylate)-co-(butylene diglycolate)s. The balance between flexibility, prompted by the furanoate-diglycolate polymeric matrix; and the high strength prompted by the bacterial cellulose fibres, enabled the preparation of a wide range of new nanocomposite materials. The new nanocomposites had a glass transition between −25–46 °C and a melting temperature of 61–174 °C; and they were thermally stable up to 239–324 °C. Furthermore, these materials were highly reinforced materials with an enhanced Young’s modulus (up to 1239 MPa) compared to their neat copolyester counterparts. This was associated with both the reinforcing action of the cellulose fibres and the degree of crystallinity of the nanocomposites. In terms of elongation at break, the nanocomposites prepared from copolyesters with higher amounts of diglycolate moieties displayed higher elongations due to the soft nature of these segments. Full article

Bio-based polyesters derived from 2,5-furandicarboxylic acid (FDCA), including poly (ethylene 2,5-furandicarboxylate) (PEF), poly(propylene 2,5-furandicarboxylate) (PPF), and poly(butylene 2,5-furandicarboxylate) (PBF) have been synthesized and modified with 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO). Copolyesters with increased glass transition temperature, good barrier and better mechanical properties, as well as higher transparency were reported in this work. The chemical structures, composition, and sequence distribution of the copolyesters were determined by ¹H NMR and ¹³C NMR. The degree of random (R) was close to 1 for all the copolyesters, indicating their random chemical structures. With the introduction of 10% CBDO units, the semi-crystalline PEF and PPF were changed into completely amorphous polyesters and the higher transparency was easily achieved. The glass transition temperature was increased from 87 °C for PEF to 91.1 °C for PETF-18, from 55.5 °C for PPF to 63.5 °C for PPTF-18, and from 39.0 °C for PBF to 43.5 °C for PBTF-18. The barrier properties investigation demonstrated that although the O₂ and CO₂ barrier of PEF/PPF/PBF were decreased by the addition of CBDO units, the modified copolyesters still showed good barrier properties. Full article