Synthesis And Properties Of 2,5 - Furanic Acid - Based Bio - Polyester

The catalytic transformation of renewable biomass into chemicals and polymer materials is an important way to solve the problem of shortage of oil resources. 2,5-Furandicarboxylic acid (FDCA) is a kind of important platform chemicals, which has a very similar chemical structure with p-phthalic acid (PTA). Therefore, FDCA can be used for polyester synthesis to substitute for PTA. In this paper, the reaction conditions and the properties of the polymer were studied.Firstly, FDCA was purified to obtain high purity FDCA. Then, the polymerization was carried out using high purity FDCA and BDO. In order to obtain the best reaction conditions, the kind of catalyst was screened, and reaction time and temperature were investigated. The synthesized polyester was characterized by Ukraine viscometer, NMR, DSC, TG and XRD. The results showed that the highest molecular weight of the polyester was obtained when tetra-n-butyl titanate was used as catalyst, and the maxium polymerization temperature was 240℃, and the best polymerization time was 3h.Secondly, the copolyesters of poly(butylene-co-1,4-cyclohexanedimethylene 2,5-furandicarboxylic acid) (PBCFs) were synthesized from FDCA, BDO and CHDM in two steps which included pre-transesterification into intermediates and subsequent intermediate polymerization. The structure of synthesized polymer was characterized by 1H NMR,13C NMR, FTIR and EA, and the effects of CHDM content on the thermal transition behaviour, thermal stability and crystallizability of the resulting PBCFs copolyesters were well studied by DSC, TG, Py-GC/MS and XRD. JH NMR and 13C NMR characterized results showed that the copolymers had random sequential structure, the triads component, average sequence length and the monomer percent in the copolymer could be adjusted by changing the feed molar ratio of BDO to CHDM. The PCF had high glass transition temperature (Tg=86.8℃), melting temperature (Tm=257.40C) and decomposition temperature (Td,max=390.7℃). PBCFs were semicrystalline or amorphous, and displayed the different Tg from 45.7 to 74.4 ℃, Tm from 140.1 to 251.9℃ and decomposition temperature from 380.6 to 388.0℃. The introduction of much more CHDM into PBCFs could enhance the higher thermal transition temperature and thermal stability.