| As the most abundant renewable resource in the world,lignocellulosic biomass is widely used.However,the utilization of lignocellulose is low due to the dense structure.In order to make lignocellulose comprehensive utilization,this paper did the following research on its pretreatment and subsequent utilization:1.Pretreatment of poplar lignocellulose with recoverable organic acid p-toluenesulfonic acid and organic solvent y-valerolactone,combined with combined hydrolysis factor(CHF)to evaluate the treatment intensity of the entire reaction process.Combined with enzymolysis and XRD measurement of the filter residue,structure characteristics analysis of lignin and HPLC determination of the filtrate,the best pretreatment condition was determined as CHF=54.99.At this pretreatment intensity,91.67%and 86.14%of hemicellulose and lignin was removed,the enzymatic hydrolysis efficiency of cellulose residue reached 84.84%,and the reaction solution contained 4.39 g/L of xylose,2.95 g/L furfural and 3.59 g/L acetic acid.The lignin weight-average molecular weight was 1587 g/mol,the hydroxyl content reached 3.64 mmol/g,and the polydispersities was 1.04.2.Using the cellulose residue obtained under the best pretreatment conditions to convert to levulinic acid.Using levulinic acid for esterification with diglycerol and 1,4-butanediol,after molecular rectification,water-based lubricating oil and low-temperature energy storage materials with excellent performance was obtained respectively.The kinematic viscosity of diglycerol ester of levulinic acid(LADLE)was 448 mm2/s and 23 mm2/s at 40? and 100?,respectively.After mixing LADLE with deionized water in a certain proportion,the high-frequency reciprocating friction test was carried out.The results showed that when the proportion of LADLE was 100%,75%and 50%,the friction coefficient and wear scar diameter was smaller.This showed that when water was mixed with the prepared water-based lubricant,it could play a good anti-friction effect,proving that LADLE could be used as a better water-based lubricant.Simultaneously prepared 1,4-butanediol ester of levulinic acid was a low-temperature phase-change energy storage substance with excellent performance.It was measured by DSC,and the results showed that the melting temperature was 50.51?,and the melting enthalpy was 156.1 J/g.3.Modifying epoxy resin by lignin and performance test.The lignin obtained under the optimal pretreatment conditions was blended with epoxy resin in different ratios,and the performance test of the modified material was conducted.The results showed that when the amount of lignin is 15%,the modified epoxy resin had the largest increase in bending strength,an increase of 87.92 MPa,an increase of 104.5%compared to pure epoxy resin;and when the amount of lignin is 5%,the impact strength of epoxy resin was the largest,increasing by 20.6%compared to pure epoxy resin. |
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