State Key Laboratory of Chemical Engineering at ZJU, Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering , Zhejiang University , Hangzhou 310027 , China.
Laboratory of Polymeric and Composite Materials (LPCM), Center of Innovation and Research in Materials and Polymers (CIRMAP), University of Mons , Mons 7000 , Belgium.
Biomacromolecules. 2019 Jan 14;20(1):353-364. doi: 10.1021/acs.biomac.8b01495. Epub 2018 Dec 3.
Poly(ethylene 2,5-furandicarboxylate) (PEF) is a biobased polyester characterized by high gas barrier properties as well as high tensile modulus and strength, but poor toughness. Toughening PEF without sacrificing its modulus, strength and gas barrier performance is a great challenge for PEF modification. In this study, high molecular weight random poly(ethylene- co-1,5-pentylene 2,5-furandicarboxylate)s (PEPeFs) were synthesized via melt copolycondensation of 2,5-furandicarboxylic acid (FDCA), ethylene glycol (EG) and 1,5-pentanediol (PeDO), a cheap, biobased and commercially available odd-carbon comonomer. The synthesized PEPeFs were characterized and assessed with intrinsic viscosity, ATR-FTIR, H NMR, DSC, TGA and tensile, impact and O permeation test. Mayo-Lewis equation with "reactivity ratio" of 3.78 for PeDO and 0.75 for EG could be used as an empirical equation to correlate the copolyester composition (ϕ) with monomer composition. PEPeFs proved nearly amorphous copolyesters having excellent thermal stability. Brittle-ductile transition was achieved at ϕ as low as 9 mol %. Increasing ϕ led to increase in elongation at break and notch impact strength and decrease in T, O barrier performance and tensile modulus and strength. However, in comparison with PEF, PEF-rich PEPeFs (ϕ 9-47%) not only showed greatly improved elongation at break (29-265% vs 4%) and enhanced impact strength (2.2-3.9 kJ/m) but also retained very high Young's modulus (2.8-3.3 vs 3.3 GPa) and yielding strength (72-83 vs 82 MPa). Particularly, when compared with bottle-grade PET, PEPeF possesses equal T (ca. 75 °C) and comparable elongation at break (ca. 115%), but greatly improved yielding strength (83 MPa) and O gas barrier property (4.8 times). As modified PEF materials possessing superior thermo-mechanical and O gas barrier properties, these integrally biobased copolyesters may find practical applications in eco-packaging and other fields.
聚（2,5-呋喃二甲酸乙二酯）（PEF）是一种生物基聚酯，具有高气体阻隔性能、高拉伸模量和强度，但韧性差。在不牺牲其模量、强度和气体阻隔性能的情况下对 PEF 进行增韧是 PEF 改性的一大挑战。在本研究中，通过 2,5-呋喃二甲酸（FDCA）、乙二醇（EG）和 1,5-戊二醇（PeDO）的熔融共聚缩聚合成了高分子量无规聚（乙烯-共聚-1,5-戊烯 2,5-呋喃二甲酸酯）（PEPeFs），PeDO 是一种廉价、生物基且市售的奇数碳共聚单体。通过特性粘度、ATR-FTIR、H NMR、DSC、TGA 以及拉伸、冲击和 O 渗透试验对合成的 PEPeFs 进行了表征和评估。Mayo-Lewis 方程中的“反应比”为 3.78（对于 PeDO）和 0.75（对于 EG），可作为经验方程，将共聚酯组成（φ）与单体组成相关联。PEPeFs 被证明是几乎无定形的共聚酯，具有优异的热稳定性。在 φ 低至 9 mol%时即可实现脆性-韧性转变。随着 φ 的增加，断裂伸长率和缺口冲击强度增加，而 T、O 阻隔性能、拉伸模量和强度降低。然而，与 PEF 相比，PEF 丰富的 PEPeFs（φ 9-47%）不仅表现出大大提高的断裂伸长率（29-265%比 4%）和增强的冲击强度（2.2-3.9 kJ/m），而且还保留了非常高的杨氏模量（2.8-3.3 vs 3.3 GPa）和屈服强度（72-83 vs 82 MPa）。特别是与瓶级 PET 相比，PEPeF 具有相同的 T（约 75°C）和可比的断裂伸长率（约 115%），但大大提高了屈服强度（83 MPa）和 O 气体阻隔性能（4.8 倍）。作为具有优异热机械性能和 O 气体阻隔性能的改性 PEF 材料，这些全生物基共聚酯可能在生态包装和其他领域得到实际应用。
