Study On In-situ Polymerization Of Poly(Butene 2,5-furan Dicarboxylate) Composites Based On Nano Titanium Dioxide

In recent years,due to the rapid development of global economy,the increase of greenhouse gas emissions has aroused people's attention to non-renewable fossil fuels.To solve these problems,we must reduce the overuse of fossil residues and strengthen the development and utilization of renewable resources.In the last few decades,scientists around the world have made considerable progress in finding renewable resources for green energy and sustainable chemical production.2,5-Furanediocarboxylic acid(2,5-FDCA)is an important representative of bio-based materials.It is regarded as an important material to replace terephthalic acid because its structure is similar to terephthalic acid.Poly(butene 2,5-furan dicarboxylate)(PBF)is a new biology-based polyester,which has excellent thermal properties and good mechanical properties.It is expected to replace its petroleum-based cousin polyester,polybutyl terephthalate(PBT).However,the crystallization rate,toughness and strength of PBF still need to be improved.Titanium dioxide(TiO₂)is a non-toxic and biocompatible material with high refractive index,good electrical conductivity,ultra-strong ultraviolet absorption capacity,excellent photocatalytic activity and so on.In this study,four kinds of nano-TiO₂ with different morphologies and crystal structures were introduced by in-situ polymerization and mixed into 2,5-furanedioic acid and 1,4-butanediol(BDO).PBF/TiO₂ nanocomposites were successfully prepared by direct esterification method.The intrinsic viscosity of PBF/TiO₂nanocomposites was measured by Uxwell viscometer at 25^oC.The viscosity of PBF was improved the most by the introduction of nanoparticles,and the composite viscosity of nano-particle components was generally about 1 d L/g.The highest viscosity was 1.2 d L/g of PBFs5 with the addition amount of 5‰nanosheet.The molecular weight of the nanocomposites was determined by GPC.The molecular weight of all the nanocomposites was higher than that of pure PBF due to the catalytic effect of nano-TiO₂.Among the four kinds of nano-TiO₂,the largest molecular weight improvement was that of the nanoparticle component,among which PBFp5 increased by 70%.65.8×103 g/mol.The structure of the composites was characterized by FT-IR and ¹H NMR spectra.No new peak was observed in all the nanocomposites,which proved that the addition of nano-TiO₂ did not change the chemical properties of PBF.X-ray diffraction(XRD),differential scanning calorimetry(DSC)and thermogravimetric analysis(TGA)were used to analyze the crystallization and thermal properties of the nanocomposites.The results of DSC and XRD showed that the introduction of all kinds of nano-TiO₂ could improve the crystallization properties of the composites,and the improvement of nano blocks and nanowires was more obvious.The nanocrystallization time of Pb Fc7 with the addition amount of 7‰was less than 1minute.The mechanical properties of the nanocomposites were characterized by impact and tensile tests.Due to the toughening of inorganic rigid particles,the mechanical properties of the nanocomposites were significantly improved.The elongation at break and impact strength increased by 119%and 570%,respectively,and the impact strength even reached95 k J/m².Through the determination of UV transmittance of nanocomposite characterization of nanocomposites of uv shielding performance,all nanocomposites on uv shielding performance showed good ascension,which nanowires components added amount to 5‰of the composite materials in the 200-400-nm can almost completely shielding ultraviolet light through the invisible area.