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以2,5-呋喃二甲酸和乙二醇为原料,草酸亚锡为催化剂,通过直接酯化法合成了线性高分子量聚2,5-呋喃二甲酸乙二醇酯(PEF).运用红外光谱(FTIR)和核磁共振氢谱(1H-NMR)表征了该聚酯的结构;由乌氏黏度计法和凝胶渗透色谱(GPC)建立了该聚酯在一种混合溶剂体系中特性黏数和重均分子量的关系:[η]=2.82×10-6Mw0.99dL/g,25℃,苯酚-四氯乙烷(1∶1,W/W);示差扫描量热法(DSC)和热失重分析(TGA)测定了该聚酯的热转变性能,结果表明该聚酯玻璃化转变温度为84℃,熔点为211℃,起始热分解温度高于370℃,具有良好的热稳定性;运用旋转流变仪研究了PEF的流变性能,结果表明,PEF熔体属于假塑性流体,随相对分子量的减小和温度升高,其非牛顿指数增大,在高于PEF熔点20～40℃,剪切速率为2.17×10-2～1.14×102s-1时,PEF的非牛顿指数为0.85左右.
In this paper, 2, 5-furandicarboxylic acid and ethylene glycol as raw materials, stannous oxalate as catalyst, a linear high molecular weight poly (2,5-furandicarboxylate) (PEF) was synthesized by direct esterification method.Using infrared spectroscopy The structure of the polyester was characterized by FTIR and 1H-NMR. The intrinsic viscosity of the polyester in a mixed solvent system was established by Ubbelohde viscometer and gel permeation chromatography (GPC) And weight average molecular weight: [η] = 2.82 × 10 -6 Mw 0.99 dL / g at 25 ° C. Phenol-tetrachloroethane (1: 1, W / W); Differential scanning calorimetry (DSC) The results showed that the glass transition temperature of the polyester was 84 ℃, the melting point was 211 ℃, the initial thermal decomposition temperature was higher than 370 ℃, and the product had good thermal stability. The rheological properties of PEF were investigated by using a rotating rheometer. The results show that the PEF melt belongs to the pseudoplastic fluid. With the decrease of relative molecular weight and temperature, the non-Newtonian index of PEF melt increases. ℃, and the shear rate is 2.17 × 10-2 ~ 1.14 × 102s-1, the non-Newtonian index of PEF is about 0.85.