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A synthetic biopolymer derived from furandicarboxylic acid monomer and hydroxyethyl-terminated poly(ether sulfone) is presented. The synthesis involves 4,4'-dichlorodiphenyl sulfone and 4,4-dihydroxydiphenyl sulfone, resulting in poly(butylene furandicarboxylate)-poly(ether sulfone) copolyesters (PBFES) through melt polycondensation with titanium-catalyzed polymerization. This facile method yields segmented polyesters incorporating polysulfone, creating a versatile group of high-temperature thermoplastics with adjustable thermomechanical properties. The PBFES copolyesters demonstrate an impressive tensile modulus of 2830 MPa and a tensile strength of 84 MPa for PBFES55. Additionally, the poly(ether sulfone) unit imparts a relatively high glass transition temperature ( T g ), ranging from 36.6 °C for poly(butylene 2,5-furandicarboxylate) to 112.3 °C for PBFES62. Moreover, the complete amorphous film of PBFES exhibits excellent transparency and solvent resistance, making it suitable for applications, such as food packaging materials.

Disulfide bonds have attracted considerable attention due to their reduction responsiveness, but it is crucial and challenging to prepare disulfide-bond-based polyesters by melt polycondensation. Herein, the inherently poor thermal stability of the S-S bond in melting polycondensation was overcome. Moreover, poly(butylene succinate-co-dithiodipropionate) (PBSDi) with a light color and high molecular weights ( M n values up to 84.7 kg/mol) was obtained. These polyesters can be applied via melt processing with T d,5% > 318 °C. PBSDi10-PBSDi40 shows good crystallizability (crystallinity 56-38%) and compact lamellar thickness (2.9-3.2 nm). Compared with commercial poly(butylene adipate-co-terephthalate) (PBAT), the elevated mechanical and barrier performances of PBSDi make them better packaging materials. For the degradation behavior, the disulfide monomer obviously accelerates the enzyme degradation but has a weaker effect on hydrolysis. In 0.1 mol/L or higher concentrations of H 2 solutions, the oxidation of disulfide bonds to sulfoxide and sulfone groups can be realized. This process results in a stronger nucleophilic attack, as confirmed by the Fukui function and DFT calculations. Additionally, the greater polarity and hydrophilicity of oxidation products, proved by noncovalent interaction analysis, accelerate the hydrolysis of polyesters. Moreover, glutathione-responsive breakage, from polymers to oligomers, is confirmed by an accelerated decline in molecular weight. Our research offers fresh perspectives on the effective synthesis of the disulfide polyester and lays a solid basis for the creation of high-performance biodegradable polyesters that degrade on demand.2 solutions, the oxidation of disulfide bonds to sulfoxide and sulfone groups can be realized. This process results in a stronger nucleophilic attack, as confirmed by the Fukui function and DFT calculations. Additionally, the greater polarity and hydrophilicity of oxidation products, proved by noncovalent interaction analysis, accelerate the hydrolysis of polyesters. Moreover, glutathione-responsive breakage, from polymers to oligomers, is confirmed by an accelerated decline in molecular weight. Our research offers fresh perspectives on the effective synthesis of the disulfide polyester and lays a solid basis for the creation of high-performance biodegradable polyesters that degrade on demand.

The demand for sustainable development has led to increasing attention in biobased polyesters due to their adjustable thermal and mechanical properties and biodegradability. In this study, we used a novel bioderived aromatic diacid, 2,5-thiophenedicarboxylic acid (TDCA) to synthesize a list of novel aromatic-aliphatic poly(alkylene adipate- co -thiophenedicarboxylate) (PAATh) copolyesters through a facile melt polycondensation method. PAAThs are random copolyesters with weight-average molecular weights of 58400 to 84200 g·mol -1 and intrinsic viscosities of 0.80 to 1.27 dL·g -1 . All PAAThs exhibit sufficiently high thermal stability as well as the highest tensile strength of 6.2 MPa and the best gas barrier performances against CO 2 and O 2 , 4.3- and 3.3-fold better than those of poly(butylene adipate- co -terephthalate) (PBAT). The biodegradability of PAAThs was fully evaluated through a degradation experiment and various experimental parameters, including residue weights, surface morphology, and molecular compositions. The state-of-the-art molecular dynamics (MD) simulations were applied to elucidate the different enzymatic degradation behaviors of PAAThs due to the effect of diols with different chain structures. The sterically hindered carbonyl carbon of the PHATh-enzyme complex was more susceptible to nucleophilic attack and exhibited a higher tendency to enter a prereaction state. This study has introduced a group of novel biobased copolyesters with their structure-property relationships investigated thoroughly, and the effect of diol components on the enzymatic degradation was revealed by computational analysis. These findings may lay the foundation for the development of promising substitutes for commercial biodegradable polyesters and shed light on their complicated degradation mechanisms.

The popularization and widespread use of degradable polymers is hindered by their poor mechanical properties. It is of great importance to find a balance between degradation and mechanical properties. Herein, poly(butylene terephthalate) (PBT) modified by SPG diol from 10% to 40 mol% were synthesized through a two-step polycondensation reaction. Chemical structures, thermal properties, mechanical properties, viscoelastic behavior and degradation of poly(butylene terephthalate-co-spirocyclic terephthalate) (PBST) were investigated. The SPG could toughen the copolyesters and the elongation at break of PBST20 was up to 260%. Moreover, the introduction of SPG enables to provide an acid-triggered degradable unit in the main chain. PBSTs copolymers maintain stable structures in a neutral environment, and the degradation under acid conditions will be unlocked. As tailoring the content of SPG, the degradation rate of the chain scission in response to acid stimuli will be adjusted. The acid degradation was proved to be occurred at the SPG units in the amorphous phase by DSC, XRD, GPC and 1 H NMR tests. After the acid degradation, the hydrolysis rate will also be accelerated, adapting to the requirements of different degradation schedules. The plausible hydrolytic pathways and mechanisms were proposed based on Fukui function analysis and density functional theory (DFT) calculation., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Nowadays, the promotion and application of aliphatic-aromatic copolyesters, such as poly (butylene adipate-co-terephthalate) (PBAT), are growing into a general trend. Although the structures of diacids exerted substantial impacts on degradation behavior, the underlying mechanisms have rarely been studied. In this work, 2,5-Furandicarboxylic acid was combined with succinic acid (PBSF), adipic acid (PBAF) and diglycolic acid (PBDF) to prepare three kinds of copolyesters. They showed unique degradation behaviors in buffer, enzyme environment and artificial seawater. These characteristics are closely related to the structural compositions of diacids. PBAFs displayed impressive biodegradability when catalyzed by Candida antarctica lipase B (CALB), while the more hydrophilic PBDFs exhibited faster hydrolysis in both buffer and artificial seawater. PBSFs, with hydrophobic and short segments, obtained a relatively slower rate of hydrolysis and enzymatic degradation. The reactivity sites and hydrolytic pathway were revealed by the combination of DFT calculation and Fukui function analysis. MD simulations, QM/MM optimizations and theozyme calculations showed that PBAF-CALB was prone to form a pre-reaction state, leading to the reduced energy barrier in the acylation process. This work revealed the effects of different structural features of diacids on polymer degradation and paved a way to design target biodegradable polymers in different degradation conditions., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Polylactic acid (PLA) is a biodegradable thermoplastic polyester produced from natural resources. Because of its brittleness, many tougheners have been developed. However, traditional toughening methods cause either the loss of modulus and strength or the lack of degradability. In this work, we synthesized a biobased and potentially biodegradable poly(butylene 2,5-furandicarboxylate)- b -poly(ethylene glycol) (PBFEG50) copolymer to toughen PLA, with the purpose of both keeping mechanical strength and enhancing the toughness. The blend containing 5 wt % PBFEG50 exhibited about 28.5 times increase in elongation at break (5.5% vs 156.5%). At the same time, the tensile modulus even strikingly increased by 21.6% while the tensile strength was seldom deteriorated. Such a phenomenon could be explained by the stretch-induced crystallization of the BF segment and the interconnected morphology of PBFEG50 domains in PLA5. The Raman spectrum was used to identify the phase dispersion of PLA and PBFEG50 phases. As the PBFEG50 content increased, the interconnected PBFEG50 domains start to separate, but their size increases. Interestingly, tensile-induced cavitation could be clearly identified in scanning electron microscopy images, which meant that the miscibility between PLA and PBFEG50 was limited. The crystallization of PLA/PBFEG50 blends was examined by differential scanning calorimetry, and the plasticizer effect of the EG segment on the PLA matrix could be confirmed. The rheological experiment revealed decreased viscosity of PLA/PBFEG50 blends, implying the possible greener processing. Finally, potential biodegradability of these blends was proved.

Aliphatic‐aromatic copolyesters offer a promising solution to mitigate plastic pollution, but high content of aliphatic units (>40 %) often suffer from diminished comprehensive performances. Poly(butylene oxalate‐co‐furandicarboxylate) (PBOF) copolyesters were synthesized by precisely controlling the oxalic acid content from 10 % to 60 %. Compared with commercial PBAT, the barrier properties of PBOF for H2O and O2 increased by more than 6 and 26 times, respectively. The introduction of the oxalic acid units allowed the water contact angle to be reduced from 82.5° to 62.9°. Superior hydrophilicity gave PBOF an excellent degradation performance within a 35‐day hydrolysis. Interestingly, PBO20F and PBO30F also displayed obvious decrease of molecular weight during hydrolysis, with elastic modulus >1 GPa and tensile strength between 35–54 MPa. PBOF achieved the highest hydrolysis rates among the reported PBF‐based copolyesters. The hydrolytic mechanism was further explored based on Fukui function analysis and density functional theory (DFT) calculation. Noncovalent analysis indicated that the water molecules formed hydrogen bonding interaction with adjacent ester groups and thus improved the reactivity of carbonyl carbon. PBOF not only meet the requirements of the high‐performance packaging market but can quickly degrade after the end of their usage cycles, providing a new choice for green and environmental protection. [ABSTRACT FROM AUTHOR]

The polyesters with high Tg (≥100°C) and good clarity are desired in fabricating heat‐resistance containers such as baby bottles, cups, medical apparatus, and kitchen appliances. In this work, a series of poly(butylene bis[4‐(2‐hydroxyethoxy) phenyl] sulfone 1,4‐cyclohexanedimethylene 2,5‐furandicarboxylate) (PBSCFs) that show superior thermal and mechanical properties against current bio‐based polyesters were synthesized via a melt polycondensation method. The accurate chemical structures of PBSCFs were confirmed by 1H‐NMR and 13C‐NMR. The SEC results show that PBSCFs have number averaged molar mass (Mn) in the range of 9700–28,500 g/mol. The Tg of PBSCFs increase from 94°C for PBSF to 108°C for PBSCF‐50 as the increasing of CHDM unit. Meanwhile, the ductility of PBSCFs also improved with the elongation at break of PBSCF‐40 increased to 223%. In addition, the PBSCF‐40 sample reported in this paper shows thermal decomposition temperature of 427°C, transmittance of 84.6%, haze of only 0.17%, tensile strength of 74.1 MPa, and tensile modulus of 2287 MPa. [ABSTRACT FROM AUTHOR]

Polyesters from renewable resources with glass transition temperature (Tg) higher than 100°C are crucial in broadening their application range. In this work, a series of high molecular weight copolyesters, poly(butylene bis[4‐(2‐hydroxyethoxy) phenyl] sulfone 2,5‐furandicarboxylate) (PBSF), was synthesized from bis[4‐(2‐hydroxyethoxy) phenyl] sulfone (BHEPS), bio‐based 1,4‐butanediol (BDO), and 2,5‐furandicarboxylic acid (FDCA) via transesterification. Nuclear magnetic resonance spectroscopy (1H‐NMR and 13C‐NMR) was used to confirm their chemical structures, composition, and sequence distribution. Characterizations demonstrated that with the increasing content of BHEPS unit, Tg of synthesized polyesters was increased from 38.2°C for PBF to 122°C for PBSF‐95, in which the content of BHEPS unit was 95%. However, the weight average molecular weight (Mw) of PBSF was dramatically decreased after the addition of BHEPS, from 95,300 g/mol for PBF to only 9600 g/mol for PBSF‐95, which was too low for practical application. Taking molecular weight, Tg, and mechanical properties into account, PBSF‐65 was considered to be a promising polyester with Mw of 28,500 g/mol, Tg of 104.7°C, tensile strength of 82 MPa, and elongation‐at‐break of 98%. Besides, it was a completely amorphous polyester with a transmittance of 89.9% by cutoff at 700 nm. Summarily, PBSF‐65 showed great potential to be used as raw material for the manufacture of baby bottles, children's toys, kitchen appliances, and beverage packaging, especially in the case when high transparency and heat resistance are required. [ABSTRACT FROM AUTHOR]

Poly(butylene terephthalate‐co‐butylene 2,5‐furandicarboxylate) copolyesters (PBTFs) were synthesized from 1,4‐butanediol, dimethyl terephthalate (DMT), and 2,5‐furandicarboxylic acid (FDCA) by a two‐step polymerization method. Their chemical structures were confirmed by Fourier‐transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and carbon nuclear magnetic resonance before thermal properties were explored with differential scanning calorimeter and thermogravimetric analyzer. Results showed that PBTFs changed from semi‐crystalline to completely amorphous when the content of FDCA unit was increased to 45 mol% at first, and then became crystallographic again with the further increment of FDCA unit to 75 mol%. For their mechanical properties, the tensile modulus and strength showed the similar trend, decreasing firstly and then increasing later. Their barrier to carbon dioxide and oxygen became better with the increasing of furan content due to the rigidity and higher polarity of furan ring. The performance of PBTFs copolyesters was investigated clearly, and the relative content of FDCA and DMT can be adjusted to satisfy different performance requirements. [ABSTRACT FROM AUTHOR]

In order to explore new substitutes for 2,5-furandicarboxylic acid (FDCA) or poly(ethylene 2,5-furandicarboxylate) (PEF) and try to develop more ideal bio-based polyesters, several thiophene-aromatic polyesters (PETH, PPTH, PBTH, and PHTH) were synthesized from dimethyl thiophene-2,5-dicarboxylate (DMTD) and different diols, including ethylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,6-hexanediol. The chemical structures of obtained polyesters were confirmed by nuclear magnetic resonance spectroscopy (1H-NMR and 13C-NMR). Determined by GPC measurement, their average molecular weight (Mw) varied from 5.22 × 104 g/mol to 7.94 × 104 g/mol with the molar-mass dispersity of 1.50–2.00. Based on the DSC and TGA results, the synthesized polyesters PETH, PPTH, and PBTH displayed comparable or even better thermal properties when compared with their FDCA-based analogues. From PETH to PHTH, their Tg varied from 64.6 °C to −1 ×C while T5% ranged from 409 °C to 380 °C in nitrogen atmosphere. PETH showed elongation at break as high as 378%, tensile strength of 67 MPa, and tensile modulus of 1800 MPa. Meanwhile, the CO2 and O2 barrier of PETH was 12.0 and 6.6 folds higher than those of PET, respectively, and similar to those of PEF. Considering the overall properties, the synthesized thiophene-aromatic polyesters, especially PETH, showed great potential to be used as an excellent bio-based packaging material in the future. [ABSTRACT FROM AUTHOR]

The conformational transition of cyclohexylene ring has been recognized as the secondary transition of polyesters containing this aliphatic ring structure. Previously, the stereochemistry, i.e., trans/cis ratio, has been identified as an important factor that has a significant impact on the conformational transition of the cyclohexylene ring. In this paper, we have proposed and proved the side chain effect as another important factor that plays the same role as the stereochemistry, due to the fact that the conformational transition of the ring is usually associated with the coupled motion of it with neighboring unit. Our strategy is to design and synthesize a series of polyesters with 1,4-cyclohexanedicarboxylic acid and diols with different side chains. Polyester without any side chain has the lowest secondary relaxation temperature (Tβ). Incorporation of asymmetric short side chain will result in increased Tβ, since it will reduce the coupled motion of the neighboring unit with the cyclohexylene ring during the conformational transition process, and thus reduces the flexibility of the chain and increases steric hindrance. However, further incorporation of long side chain will result in decreased Tβ because of the plasticization effect. Moreover, we also found that polyesters with low Tβ tend to have not only better impact strength, but also good ductility and elasticity. Our study enables people to take advantage of the cyclohexylene ring structure for the design and synthesis of thermoplastic and elastomer with better performance. [ABSTRACT FROM AUTHOR]

ABSTRACT The bio-based polyester, poly(ethylene 2,5-furandicarboxylate) (PEF), was modified by 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO) via copolymerization and a series of copolyesters poly(ethylene-co-2,2,4,4-tetramethyl-1,3-cyclobutanediol 2,5-furandicarboxylate)s (PETFs) were prepared. After their chemical structures and sequence distribution were confirmed by nuclear magnetic resonance (1H-NMR and 13C-NMR), their thermal, mechanical, and gas barrier properties were investigated in detail. Results showed that when the content of CBDO unit in the copolyesters was increased up to 10 mol%, the completely amorphous copolyesters with good transparency could be obtained. In addition, with the increasing content of CBDO units in the copolyesters, the glass transition temperature was increased from 88.9 °C for PET to 94.3 °C for PETF-23 and the tensile modulus was increased from 3000 MPa for PEF to 3500 MPa for PETF-23. The barrier properties study demonstrated that although the introduction of CBDO units would increase the O2 and CO2 permeability of PEF slightly, PECF-10 still showed better or similar barrier properties compared with those of PEN and PEI. In one word, the modified PEF copolyesters exhibited better mechanical properties, higher glass transition temperature, good barrier properties, and better clarity. They have great potential to be the bio-based alternative to the popular petroleum-based poly(ethylene terephthalate) (PET) when used as the beverage packaging materials. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3298-3307 [ABSTRACT FROM AUTHOR]

A series of bio-based polyesters were synthesized by melt polycondensation of itaconic acid with diols and glycerol without VOC emission. Their chemical structures were confirmed by FT-IR and 1H-NMR before they were made to copolymerize with acrylated epoxidized soybean oil (AESO). The thermal and mechanical properties of the resulting thermosets were investigated by differential scanning calorimetry (DSC), tensile testing and dynamic mechanical analysis (DMA). Their coating properties on tinplate and glass plate were also studied. Results showed that the tensile strength, modulus, glass transition temperatures and bio-based content of the AESO-based thermosetting resins were significantly improved after the introduction of the synthesized polyesters. In addition, the modified AESO systems could be well coated on the surface of tinplate and glass plate and good coating properties such as hardness, flexibility, adhesion, solvent resistance and water absorption were demonstrated. They showed great potential for applications as coatings, adhesives and composites. [ABSTRACT FROM AUTHOR]

Synthesized a novel bio-based polyester from 2,5-furandicarboxylic acid and citric acid with excellent mechanical and gas barrier properties. [Display omitted] • New bio-based polyesters from furandicarboxylic acid. • Excellent mechanical properties. • Good gas barrier properties. • Applied as packaging materials. Biobased feedstocks developed from renewable resources play a crucial role in polymers. Dimethyl octahydro-2,5-pentalenediol (MeOPD) with excellent thermal stability and rigidity is a biobased bicyclic diol derived from citric acid. In this work, MeOPD was first reacted with dimethyl carbonate (DMC) to form oligo (dimethyl octahydro-2,5-pentalenediol carbonate) (OMC). Subsequently, a series of poly(butylene-co-dimethyl octahydro-2,5-pentalenediol furanoate-co-carbonate) (PBMFC) polyesters with MeOPD units ranging from 5 to 31 mol% were synthesized via melt polycondensation from OMC, dimethyl furan-2,5-dicarboxylate (DMFD) and 1,4-butanediol (BDO). Due to the low reactivity of MeOPD, its actual content in copolymer is much lower than that in the feed, and as the MeOPD content rises, the number-average molecular weight of PBMFCs drops from 25,200 g/mol of PBMFC5 to 12,800 g/mol of PBMFC31. Despite the presence of MC units weakens thermal stability, PBMFCs still maintain good thermal stability, evidenced by T d,5% ranging from 294-325 °C in N 2 and from 295-339 °C in air. The mechanical properties are also satisfactory, exhibiting tensile modulus ≥ 500 MPa, tensile strength ≥ 23 MPa, and elongation at break ≥ 150 %. Compared to PET, PBMFCs demonstrate commendable gas barrier properties, with CO 2 and O 2 barrier capability being 4.7–11.0 times and 2.0–3.6 times that of PET, respectively. All results indicate that PBMFCs can serve as a renewable potential material for packaging application. [ABSTRACT FROM AUTHOR]

Bio-based and biodegradable polymers opens up opportunities to overcome resource depletion and plastic pollution. However, the degradation mechanism based on ester bond breakage makes it difficult to achieve controllable degradation induced by external stimuli. In this work, we present a new 2,5-furandicarboxylic acid-based copolyesters (PBFDi) by partially replacing carbon–carbon backbones with disulfide bonds and discuss the influence of disulfide bonds on thermal stability, crystallization behavior, mechanical and barrier properties of polyesters. They could maintain stable for 1 h at processing temperatures of 220 °C, meeting the needs of long-term melt processing. The asymmetric structure of the furan ring and the slower free rotation of disulfide bonds help restrict the mobility of chains and obstruct gas permeation, resulting in 9.3–126.7 times increase in O 2 barrier than commercial PBAT. With the introduction of small amount (≤40 %) of disulfide bond units, the hydrolysis rate is relatively slow and can maintain stable during storage and use. As expected, the copolyesters show redox dual-responsive degradation. Even at low concentrations (0.01 M and 0.1 M) of H 2 O 2 , the transition from hydrophobicity to hydrophilicity can be achieved, expected to accelerate the hydrolysis of PBFDi. The fast cleavage of disulfide bonds induced by DTT could be influenced by the copolymerized FDCA units. Lastly, the redox dual-responsive mechanism is elucidated, and how the rigid FDCA co-monomers affect the redox dual responsiveness is also clarified. [Display omitted] • Bio-based and high gas barrier PBFDi copolymer for green packagings. • The asymmetric furan ring and slow rotation of disulfide bonds restricted chain motion. • The PBFDi transformed from hydrophobicity to hydrophilicity at low concentrations of H 2 O 2. • Smart degradation under mild stimuli of redox reagent. [ABSTRACT FROM AUTHOR]

Synthesis of bio-based high gas barrier polyesters based on furandicarboxylic acid: trade-off between ethylene and propylene diols. [Display omitted] • Bio-based polyesters. • 2,5-Furandicarboxylic acid. • Good gas barrier properties. • Trade-off between ethylene and propylene diols. • Excellent thermal–mechanical properties. A series of bio-based poly(ethylene-co-propylene furandicarboxylate) (PEPF) copolyesters with different compositions were synthesized from dimethyl-2,5-furandicarboxylate, ethylene glycol and 1,3-propanediol by transesterification and melting polycondensation. Their chemical structure, composition and sequence distribution were confirmed by 1H NMR and 13C NMR. The results of GPC showed that the obtained copolyesters had a high number average molecular weight between 25000 g/mol and 30900 g/mol. The thermal properties characterized by DSC showed that the T g increased with the mole fraction of EF from 64.4℃ for PEPF-23 to 83.2℃ for PEPF-84 as well as the samples displayed a high Young's modulus between 2800 and 3360 MPa and tensile strength between 56 and 89 MPa. Furthermore, the PEPF copolyesters exhibited excellent CO 2 , O 2 and H 2 O barrier properties compared with poly(ethylene terephthalate) with the BIFp of 8.7–10 times, 3.7–4.4 times and 1.5–1.6 times, respectively. The transparency of PEPFs was up to 89% by cutoff at 700 nm and had better solvent resistance. This work builds a bridge between poly(ethylene 2,5-furandicarboxylate) and poly(propylene 2,5-furandicarboxylate) and PEPFs owned excellent thermo-mechanical and gas barrier properties could be used in food packaging fields. [ABSTRACT FROM AUTHOR]

Graphical abstract Bio-based polyester demonstrating extremely high crystalline, good thermal and mechanical properties was synthesized from FDCA and 1,4-cyclohexanedimethanol with different steric conformation. Highlights • PCF was synthesized from FDCA and CHDM with different steric conformation. • The melting temperature of PCF could be high up to 294 °C and its crystallization half-time could be only several seconds. • The mechanical properties and thermal stability of PCF were comparable to or better than those of PET or PBT. • PCF has great potential to be used as a bio-based polyester engineering plastic. Abstract The bio-based polyester demonstrating great potential to be used as engineering plastic, poly(1,4-cyclohexanedimethylene furandicarboxylate) (PCF) was synthesized from furandicarboxylic acid (FDCA) and 1,4-cyclohexanedimethanol (CHDM) with different steric conformation. After the chemical structures were identified by nuclear magnetic resonance (1H NMR and 13C NMR) and molecular weight was determined by gel permeation chromatography (GPC), their crystallization behaviors, thermal and dynamic mechanical properties were investigated by differential scanning calorimeter (DSC), thermogravimetric analyzer (TGA) and dynamic mechanical analysis (DMA). Results showed that PCFs demonstrated very good crystalline properties and the steric configuration of CHDM, i.e. the ratio of cis - to trans -CHDM in PCFs, had significant influences on their properties. The melting temperature of PCF could be as high as 294 °C and its crystallization half-time could be only several seconds. In addition, its mechanical properties and thermal stability were comparable to or better than those of poly(ethylene terephthalate) (PET) or poly(butylene terephthalate) (PBT). Considering the overall performance of PCF, it has great potential to be used as the bio-based polyester engineering plastics. [ABSTRACT FROM AUTHOR]

Abstract The bio-composites of poly (lactic acid) (PLA) involving a varied mass fraction of precipitated barium sulfate (BaSO 4) were prepared via melt-compounding and subsequent injection molding. The morphologies, impact toughness and thermal properties of the composites were investigated carefully, and the toughening mechanism was emphasized by a combination of BaSO 4 content and the crystallization ability. Results showed that an adequate amount of BaSO 4 could disperse homogeneously in PLA matrix with well-bonded interfaces. The impact toughness was increased significantly by 52.7% due to added inorganic particles as well as the increased actual crystallinity of the composites. The added BaSO 4 let the cold crystallization occur earlier (shifting to low temperature) while suppressing the cold crystallinity of PLA phase. Such inhibition effects derived from the increased inorganic filler were then further explored and confirmed by the kinetic analysis on the cold crystallization under non-isothermal conditions. Indeed, the added BaSO 4 increased the crystallization half-time and crystallization parameter of F(T) based on Mo equation. Moreover, the activation energy on cold crystallization was strengthened along with the increasing BaSO 4. It seemed that there is little change in the reaction order of PLA/BaSO 4 bio-composites, following the unique reaction thermal decomposition, whereas the activation energies were decreased steadily based on Carrasco method. Graphical abstract The graphical abstract showed the morphological structures, particle size, and distributions, the effect of BaSO 4 content on the impact toughness, as well as the activation energy as a function of relative crystallinity. Image 1 Highlights • Precipitated barium sulfate can disperse homogeneously with well-bonded interfaces in PLA matrix. • The impact toughness is improved remarkably higher than 50%. • The added inorganic fillers restrain the cold crystallization. • Increased barium sulfate don't change reaction order but decreased activation energy of thermal decomposition. [ABSTRACT FROM AUTHOR]

Poly(ethylene- co -1,4-cyclohexanedimethylene 2,5-furandicarboxylate) (PECF), with different contents of trans - or cis -CHDM isomers, was synthesized to investigate the influence of CHDM configuration on its properties. Before properties investigation, their chemical structures, composition and molecular weight as well as molecular weight distribution were determined by nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). Their thermal and dynamic mechanical properties as well as barrier properties were measured by differential scanning calorimeter (DSC), thermogravimetric analyzer (TGA), dynamic mechanical analysis (DMA) and gas permeability tester. Results showed that the PECFs could be changed from amorphous polyester (PECF-trans 25) to highly crystalline polyester (PECF-trans 98) by increasing the content of trans -CHDM from 25% to 98%. The melting temperature of PECF-trans 98 was as high as 252 °C and its crystallization half-time was only 15 s. Besides the tensile modulus and strength, the O 2 and CO 2 barrier property of PECFs were all increased with the increasing content of trans -CHDM. When the content of trans -CHDM was higher than 55%, PECFs showed excellent gas barrier properties, which was better or comparable to those of PEN and PEI. [ABSTRACT FROM AUTHOR]

A series of poly(ethylene- co -1,4-cyclohexanedimethylene 2,5-furandicarboxylate)s (PECFs) with different compositions were synthesized from 2,5-Furandicarboxylic acid (FDCA), 1,4-cyclohexanedimethylene (CHDM) and ethylene glycol (EG). Their chemical structures, composition and sequence distribution were determined by FT-IR, 1 H NMR and 13 C NMR. The composition of the resulted polyesters could be controlled by the feed mole ratio of CHDM to dimethyl furan-2,5-dicarboxylate (DMFD). And for all the copolyesters, the degree of randomness (R) was close to 1, indicating their randomness. Their thermal and mechanical properties were investigated by Differential Scanning Calorimeter (DSC) and tensile testing, results showed that the crystallizability, tensile modulus and strength of PECFs were decreased with the increasing content of CHDM at first (0–59%), and with the introduction of more CHDM (76–100%) units, they were increased accordingly. However the elongation at break was changed contrarily. The barrier properties study demonstrated that although the O 2 and CO 2 permeability of PEF was increased by the introduction of CHDM, PECF-32 and PECF-76 still showed excellent barrier properties, which were better or comparable to those of PEN and PEI. [ABSTRACT FROM AUTHOR]

Synthesized a novel bio-based polyester from 2,5-furandicarboxylic acid and 2,3,5,6-tetrafluoro-1,4-benzenedimethanol with excellent heat resistance, transparency and gas barrier properties. [Display omitted] • New bio-based fluorinated polyesters. • High glass transition temperature. • Excellent transparency. • Good gas barrier properties. • Applied as packaging materials. The polyesters derived from renewable resources with both high transparency and good heat resistance are urgently desirable. Destroying the crystallization of a material and achieving an amorphous state can ensure high transparency, while good heat resistance can be provided by rigid monomers. Herein, the fluorinated rigid diol 2,3,5,6-tetrafluoro-1,4-benzenedimethanol (TFBDO) was introduced into 2,5-furandicarboxylic acid (FDCA)-based copolyesters to synthesize a series of new bio-based polymers called poly(ethylene-1,4-cyclohexyldimethylene-2,3,5,6-tetrafluoro-1,4-benzenedimethanol 2,5-furandicarboxylate) (PECFF) with different TFBDO contents via a two-step melt polycondensation. The number average molecular weight (M n) of 24,200 ∼ 46,700 g/mol and the polydispersity index (PDI) of 1.28 ∼ 1.74 for synthesized PECFFs showed the high reaction activity as a rigid diol of TFBDO. As the increasing of tetrafluoro-1,4-benzenedimethanol unit, the T g was improved from 91 °C for PECFF-15 to 118 °C for PECFF-75, and the thermal stability of T d,5% in nitrogen increased from 371 to 393 °C as well as the hydrophobicity, and gas barrier properties were also improved. When the content of the tetrafluoro-1,4-benzenedimethanol unit was up to 60 %, the copolyester PECFF-60 exhibited the T g of 113 °C, T d,5% of 421 °C, Young's modulus of 2460 MPa, and tensile strength of 71 MPa. Moreover, the surface water contact angle increased from 85° to 101° as well as the CO 2 and O 2 barrier properties improved 43.3-fold and 8.6-fold compared with PET. These studies have shown that the new bio-based polyester could be a potential application in many fields, such as transparent sheet in outdoor, architectural materials or electronic equipment, and non-food contact packaging. [ABSTRACT FROM AUTHOR]

• A new PBSTh copolyesters were synthesized from bio-based 2,5-TDCA. • Excellent mechanical properties and O2 barrier properties. • Outstanding biodegradability and higher degradation rates in enzymatic and compost environments. Lacking available eco-friendly aliphatic-aromatic copolyesters with balanced mechanical properties, gas barrier properties and biodegradability is a foremost challenge in the field of degradable materials. 2,5-thiophenedicarboxylic acid (2,5-TDCA) as a new aromatic monomer with five-membered aromatic-ring can be synthesized from the renewable glucaric or muconic acid. In this work, a series of poly(butylene succinate-co-butylene 2,5-thiophenedicarboxylate) (PBSTh) copolyesters with TDCA units ranging from 10 to 80 mol% were synthesized by melt polycondensation. The results of 1H-NMR, 13C-NMR and GPC revealed that the obtained random copolyesters possessed high number-average molecular weight from 54,800 to 88,600 g/mol. The copolymerized TDCA units was beneficial to improve the thermal stability, and T d,5% in N 2 rose from 324°C of poly(butylene succinate) (PBS) to 344∼371°C of PBSThs. The mechanical properties of PBSThs were good with tensile modulus >29 MPa, tensile strength >11.4 MPa and elongation at break >523%, respectively. PBSThs showed better gas barrier properties than the well-known poly(butylene adipate-co-butylene terephthalate) (PBAT) and the BIFps of CO 2 and O 2 were 5.1∼60.2 times and 5.1∼32.0 times to PBAT, respectively. Also, the excellent biodegradability was proved both in enzymatic and compost environments and PBSThs have higher degradation rates than PBAT when the content of TDCA unit is lower than 60 mol%. In conclusion, the investigation of PBSThs has shown that the incorporation of 2,5-TDCA is effective in enhancing the overall properties of PBS and PBSTh can be a promising candidate in the field of biodegradable polymers. [ABSTRACT FROM AUTHOR]

Non-planar ring contained polyester is synthesized as an effective toughening agent to modify polylactide (PLA). By systematically researching the relation between molecular structure and properties, the two key factors to pursue high toughness of PLA with non-planar ring contained polyester are carefully distinguished. For one thing, the polyester must own the ability to be well compatible with PLA. For the other, the polyester should have a rigid molecular chain but “non-rigid” aggregation structure. By suitably controlling the molecular design, poly(butylene adipate- co -1,4-cyclohexanedicarboxylate) (PBAC) is obtained. After using PBAC to toughen PLA, the elongation extremely increases to 196.1 ± 3.6% and the notched impact strength is also effectively improved with several times. Finally, our research establishes an important methodology to toughen PLA and thus fabricates tough PLA based blends. [ABSTRACT FROM AUTHOR]

• PBDFs in the full composition range were prepared using bio-based or potential bio-based monomers as raw materials. • Diglycolic acid improves the hydrophilicity of PBDFs, thereby accelerating their degradation rates. • All PBDFs exhibited better gas barrier properties than PBAT. • PBDF40 is a prospective substitute for PBAT for food packaging materials with gas barrier requirements. Poly(butylene adipate- co -terephthalate) (PBAT) is a flexible aliphatic/aromatic copolyester commercialized for degradable plastics, while the slow degradation rates and poor barrier properties limit its applications. Consequently, it is highly desirable to develop materials with faster degradation rates and enhanced barrier properties. Here, we synthesized poly(butylene diglycolate- co -furandicarboxylate) (PBDF) copolyesters by transesterification and melt polycondensation. The NMR spectra confirmed their structure and composition. Besides, the thermal, mechanical, permeable and degradable properties were characterized thoroughly. It was found that the properties were dependent on chemical composition and crystallinity. Actually, the introduction of diglycolic acid (DGA) comonomer hinders the crystallization and all the copolyesters appear as semicrystalline polyesters except for PBDF80. Among them, PBDF40 possesses outstanding mechanical properties with an elastic modulus of 165 MPa, tensile strengths of 54 MPa, and elongations of break of 654%. Moreover, the CO 2 and O 2 barrier properties of PBDF40 are 68.6 and 45.9 times higher than those of PBAT. PBDFs also exhibit accelerated rates in hydrolysis and composting degradation, which could be attributed to the enhanced hydrophilicity due to the electronegativity of ether-oxygen atoms in DGA. In particular, the mass loss of PBDF40 reaches 46% and 42% after 28 days of CALB enzymatic degradation and 8 weeks of compost degradation, respectively. These results highlight that the synthesized polyesters, especially PBDF40, demonstrate potential application in food packaging. [ABSTRACT FROM AUTHOR]

• A novel class of environmentally degradable copolyesters were prepared. • With fixed aromatic but varied aliphatic units, properties could be controlled precisely. • The poor gas barrier of PBAT could be drastically improved by diglycolate. • Diglycolic acid played a key role in the polymer hydrolysis. • PBADTs exhibited the good storage stability in a low humidity environment. Aliphatic–aromatic copolyesters are indispensable in degradable plastics, but their properties are limited by low strength and modulus, and slow degradation rates in natural environment. Herein, we report a novel molecular design method to prepare poly(butylene adipate–co–diglycolate–co–terephthalate)(PBADT) copolyesters. In detail, the aromatic unit is fixed at 50% molar content of butylene terephthalate (BT) units, while the aliphatic units are consisted of butylene adipate (BA) and butylene diglycolate (BD) units. The PBADT copolyesters have melting temperatures higher than 130 °C and manifest rapid crystallization, high elastic modulus (>129 MPa) and satisfied ductile tensile behavior (>770%). Their gas barrier performance and hydrophilicity all increase with increasing BD units. Compared with PBAT, faster hydrolysis and seawater degradation are observed, which is explained by the more hydrophilic structure of diglycolate. This work provides insights and direction for the development of high-performance yet environmentally degradable alternatives to conventional biodegradable aliphatic–aromatic polyesters. This work provides insights and direction for the development of high-performance yet environmentally degradable alternatives to conventional biodegradable polyesters. [Display omitted] [ABSTRACT FROM AUTHOR]

The hybrid polydiols composed of high and low crystalline polyesters were used as the degradable soft segments for desirable polyurethane. Moreover, the dynamic disulfide bond was introduced to simultaneously endow the polyurethane with self-healing and anti-aging properties. Consequently, the polyurethane integrated room temperature self-healing, anti-aging and controlled degradation capacities. • The self-healing and anti-aging could be simultaneously realized by disulfide bonds. • Degradable soft segments protected by hard segments lead to controlled degradation. • Self-healing, anti-aging and controlled degradation are integrated in a polyurethane. Two of the very important demands for the elastic matrix of electronic skin (E-skin) are durability and degradability, which ensure the stable performance in daily life and green end of the E-skin. Unfortunately, these two requirements are usually incompatible. Here, we proposed the idea of controlled degradation and synthesized a polyurethane, AL-PU-4, to solve such challenge. High crystalline hydroxy-terminated poly (1,4-butylene adipate) (HTPBA) and low crystalline polycaprolactone diol (PCL diol) were mixed and used as the degradable soft segment. The dynamic disulfide bond was chosen as the chain extender, which could simultaneously endow the polyurethane with anti-aging and self-healing properties. The AL-PU-4 didn't show significant loss in mechanical and molecular weight after 12 days of accelerated aging experiment, which equaled to 12 months of daily use, and it owned a fast room temperature self-healing speed of 1.31 μm/min. With the steric protection of the hard segment, the degradation of ester bonds in HTPBA and PCL diol segments was seriously retarded under enzymatic and low pH conditions. Only when the pH reached 14, the 'lock' on degradation was opened. The above functionalities were also verified in an E-skin demo, which could response the external pressure quickly and show high stability in cyclic test. [ABSTRACT FROM AUTHOR]

In polymer science and industry, the important role of thermosetting resin is well-recognized. However, most thermosets suffer from the overdependence on petroleum resource and in addition are linked to environmental concerns. The development of sustainable thermosetting resins thus has become an objective of contemporary research. Addressing this need generally requires renewable feedstocks, satisfied comprehensive properties, and long service life or recyclability. Herein, a systematic overview regarding recent advances in sustainable thermosetting resins is provided. Firstly, the origins and access of bio-based platform compounds successfully applied in the bio-based thermosetting resins are being discussed. Subsequently, the synthesis, structure-property relationships, and methodologies for the functionalization of three typical bio-based thermosets, including benzoxazine, epoxy resin and unsaturated polyester, are being reviewed. Finally, strategies for the recycling of bio-based thermoset waste products are being presented. The objective of this work is not only to summarize the recent progress on sustainable thermosets, but also help us understand them more deeply and widely in a short time, so as to promote their faster development. Image, graphical abstract [ABSTRACT FROM AUTHOR]