| China is a big agricultural country,in the country side the rural crop residues usually was consumpted by burning,which not only brought the waste of resources,but also pollute the environment.With the awareness of environmental protection and the efficient use of renewable resources,it becomes the focused and hot topic to make full use of biomass.Due to the complexity of the structure and composition of biomass,the efficient utilization of biomass becomes difficult.As the development of technology,many researchers have been focused on the liquefaction and gasification to prepare the liquid fuel.The strategy is to hydrolyze the biomass combined with the physical-chemical process to prepare high value-added products.In this study,the glucose as the raw material to prepare platform compound levulinic acid catalyzed by the magnetic solid super acid.The molecular formula of levulinic acid consist of carbonyl and carboxyl,which can take reaction of esterification,salt,condensation,halogenation and so on.Two kinds of PVC plasticizers were prepared through the levulinic acid by esterification and condensation.Compared with the traditional DOP plasticizer,the plasticizer prepared in this paper has improved the migration resistance,thermal stability and mechanical properties.A self-curing epoxy resin was prepared by levulinic acid instead of acetone.A flexible epoxy resin was prepared by the esterification between the levulinic acid and monobasic long chain alcohols.Compared with the 128 epoxy cured,the epoxy in this study has improved the flexibility,toughness and low elongation break.The specific research includes the following five parts:1.the synthesis and catalytic ability of magnetic solid superacid S2O82-/ZrO2-TiO2-Fe3O4The magnetic solid superacid S2O82-/ZrO2-TiO2-Fe3O4 was synthesized by chemical coprecipitation method.The catalyst was characterized by IR,X-ray diffraction,nitrogen adsorption,ammonia adsorption and desorption and saturated magnetic intensity.Through the X-ray characterization,it can be seen that the crystal of catalyst was changed after high-temperature calcination.The change of crystal brought a higher acidity.The result can be confirmed by ammonia adsorption and desorption experiment.An average pore size of 1.75 nm and BET surface area of 27.3 m2/g were obtained through the nitrogen adsorption.The saturated magnetic intensity of the catalyst was up to 13.4265 emu/g,which effectively improved the recovery and utilization of catalyst.The levulinic acid was prepared from glucose by S2O82-/ZrO2-TiO2-Fe3O4,and the synthesis process was optimized.A yield of levulinic acid was upto 70.2% at the condition of glucose concentration 30 g/L,catalyst concentration 3 g/L,reaction temperature 200 ?,reaction time 45 min and catalyst calcination temperature 600 ?.The kinetic parameters was also been studied,the activation energies of glucose hydrolysis were Ea1=109.2 kJ/mol ? Ea2=81.2 kJ/mol ? Ea3=159.1 kJ/mol and Ea4=109.3 kJ/mol.Compared with the activation energies catalyzed by liquid acid,the activation energies of this study were lower.In conclusion,S2O82-/ZrO2-TiO2-Fe3O4 is with high catalytic efficiency for the levulinic acid preparation from glucose hydrolysis.2.the synthesis and properties of levulinic acid pentaerythritol ketal ester plasticizerThe levulinic acid pentaerythritol ketal ester(LAPKE)prepared from levulinic acid,pentaerythritol and glycol through esterification and ketalation.The structure of LAPKE was characterization by IR,1H-NMR and 13C-NMR.Using the LAPKE as the plasticizer,the performance of PVC was studied when the PVC were added by 30wt% of LAPKE and DOP.The test included thermogravimetry(TG),dynamic thermomechanical analysis(DMA),extraction,volatility and mechanical thermal stability.The results showed that the existence of four ester groups increased the compatibility between PVC and plasticizer.Compared with DOP plasticized PVC,the migration from solution and volatility were better.The mechanical thermal stability time was significantly improved from 8.45 min to 23.35 min.From the TG analysis,it can be seen that the initial thermal decomposition temperature has increased from 253.6 ? to 277.1?,and the maximum decomposition rate temperature has also increased.As the plasticizers were added according to the mass ratio of 1:1,the result showed that the elongation break was 372%,the tensile strength was 33 MPa,and the shore hardness was 45.1.At the same condition,the properties of DOP plasticizing PVC were elongation break of 357%,the tensile strength of 19 MPa and shore hardness of 42.3.3.the synthesis and properties of bisphenol acid epoxyBisphenol acid was prepared from levulinic acid and phenol by condensation reaction through molecular design.And then the diphenolic acid epoxy was prepared by diphenolic acid and epoxy chloropropane.At high temperature,the diphenolic acid epoxy was curing to film.The structure of diphenolic acid epoxy was characterized by hydrogen nuclear spectrum and FT-IR.Its performance was studied by thermogravimetric,different scanning calorimetry,adhesion tester,pencil scratching tester and elasticity tester.The hot water resistance,solvent resistance and chemical corrosion resistance of diphenolic acid epoxy were also measured.The results showed that the diphenolic acid epoxy curing film was with good thermal stability,and its glass transition temperature was up to 70.86?.Through the mechanical property test results showed that the adhesion is grade 1,and pencil hardness is 9 H.It quality loss is nearly zero after immersed in hot water for 3 h.In addition to acetone and alkali solution,the solvent resistance,acid and salt corrosion of diphenolic acid epoxy curing film is good.4.the synthesis and properties of bisphenylether isooctyl ester epoxy resinThe levulinic acid propionate was prepared using the levulinic acid and isooctyl alcohol as the raw materials through the esterification.The acetone was instead by levulinic acid propionate to prepare bisphenol iscohol ester.Finally,the epoxy bisphenol isoocyl alcohol ester was prepared by bisphenol iscohol ester and epoxy chloropropane.The structure of epoxy bisphenol isoocyl alcohol ester was characterized by IR and 1H-NMR.Three epoxy cured were studied including epoxy 128,epoxy 128 and BEAIAE(the weight ratio of 1:1),BEAIAE reacted with curing agent D230.The result showed that the elongth break was increased from 1.73% obtained by epoxy 128 cured to 99.02% from BEAIAE cured.The SEM photo showed that the fracture surface was relatively rough with the presence of BEAIAE,which indicated that it should be a ductile fracture,while the fracture surface of epoxy 128 cured was smooth.It belonged to the brittle rupture.The glass transition temperature of 88.83??42.23?and 10.99? were obtained by different scanning calorimeter?It can be seen that BEAIAE can efficiently decrease the Tg.At the room temperature,the shore hardness was tested,and they were 84,72 and 19.The thermogravimetric analysis data indicated that the maximum thermal decomposition rate temperatures were almost the same.In conclusion,the existence of BEAIAE can efficiently improve the brittleness and flexibility of epoxy resin 128.5.the synthesis and properties of epoxy bisphenylether isooctyl ester PVC plasticizerThe PVC samples added by 30wt% plasticizer including the DOP and epoxy phenolic acid isooctanol ester(BEAIAE)as the plasticizer were prepared.The PVC samples properties were tested by thermogravimetry,dynamic thermomechanical analysis,scanning electron microscopy,thermal aging oven,extraction,volatilization and thermal decomposition kinetics.The results showed that the Tg plasticized by DOP was lower,and its storage modulus was lower at high temperature.While the storage modulus of PVC samples plasticized by BEAIAE was lower at low temperature.It indicated that PVC plasticized by BEAIAE has good low temperature flexibility.Because of the epoxy group in the structure,the thermal stability time was much longer,and the extraction and volatile ability was low.Activation energy of 95.65 kJ/mol was obtained from the thermal decomposition kinetic,which indicated a better thermal stability.It can be seen from the SEM photo of fracture surface many small and dense cavities existed.All in all,benzene ring,ester group and epoxy group in the molecule of BEAIAE brought good thermal stability and resistance to migration. |
PDF Full Text Request