聚对苯二甲酸二甲酯/聚2,5-呋喃二甲酸二甲酯嵌段聚酯的合成与表征

以生物基单体2,5-呋喃二甲酸、乙二醇为原料合成聚2,5-呋喃二甲酸乙二醇酯(PEF)。采用熔融酯交换法以PEF聚酯部分取代聚对苯二甲酸乙二醇酯(PET),制备了系列PET-b-PEF嵌段共聚酯。通过核磁共振仪(NMR)、差示扫描量热仪(DSC)、热失重仪(TGA)、X射线衍射仪(XRD)等技术手段表征了共聚酯的结构和性能。结果表明,该系列共聚酯的玻璃化转变温度(Tg)在75.8~80.3℃之间,且随着PEF链段质量分数的增加,PET-b-PEF嵌段共聚酯的Tg先降低后升高,结晶度和熔融温度逐渐降低。当PEF链段含量高于15%时,共聚酯没有结晶峰。该系列共聚酯具有良好的热稳定性,起始分解温度在392.2~407.9℃之间,与所制备的PET起始分解温度403.3℃接近。且当共聚酯中PEF链段含量低于15%时,起始分解温度均在407℃左右,优于PET的热稳定性。

Synthesis and Characterization of Polyethylene Terephthalate-b-poly(ethylene 2,5-furandicarboxylate) Block Polyester

Poly(ethylene 2,5-furandicarboxylate)(PEF) was synthesized based on 2,5-furanicarboxylica acid and ethylene glycol. Polyethylene terephthalate-b-poly(ethylene 2,5-furandicarboxylate)(PET-b-PEF) block copolymers were prepared by melt transesterification method. PET was partly replaced by PEF polyester. The properties of PET-b-PEF block copolymers were characterized by nuclear magnetic resonance spectormeter(NMR), differential scanning calorimeter(DSC), thermo gravimetric analysis(TGA) and X-ray diffraction(XRD). The results show that the glass transition temperature(T_g) of copolyesters is about 75.8~80.3 ℃. The T_g of the PET-b-PEF block copolyesters first decreases and then increases; the crystallinity and the melting temperature decrease with the increasing contents of PEF segments, moreover, there is no crystalline diffraction peaks for the copolyesters when the chain segment content of PEF is higher than 15%. The initial decomposition temperature of this series of copolyesters is about 392.2~407.9 ℃. PEF has excellent thermal properties similar to that of PET(403.3 ℃). In addition, the thermal stability of the copolyesters is better than that of PET, when the chain segment contents of PEF in the coplyester is less than 15%, and the initial decomposition temperature of PET-b-PEF block copolymers is close to that of PET.