The Oxidation Of Lignin In The Ionic Liquid [BMIm]Cl And Epoxy Resin Synthesis

Lignin content is only less than cellulose in nature, is the second largest renewable resources as known. So far, the efficient use of lignin by annual produced by industrial is less than 5% of the total industrial lignin, the vast majority in the industrial wastewater was treated as sewage discharge, it causes the waste of resources, and emissions of industrial wastewater containing lignin, causing severe damage to the environment.Therefore, in recent years, the lignin in materials research has received the widespread attention, scholars at home and abroad through changing the structure of the lignin, improving activity of lignin, replacing part of the stone and chemical products to synthesize polymer materials.In this paper, combining with the characteristics of physical and chemical properties of lignin and the chemical structure and on the basis of comprehensive literature using industrial alkali lignin (LG) as raw material, use ionic liquid [BMIm]Cl to replace the traditional organic solvent, using H2O2 as oxidant to oxidative the lignin, then get the oxidated lignin (OLG), so as to improve the reactivity of lignin.Then use the modified oxidated lignin (OLG) and epoxy chloropropane (ECH) in alkaline conditions and having epoxidation reaction to get the lignin-epoxy resin (LGEP), using LGEP epoxy value for the response, to explore the effects of reaction conditions on LGEP synthesis reaction, and establish the autocatalytic reaction model to analysis the curing reaction of LGEP preliminary dynamic.First of all, pretreatment, alkali lignin materials will be through the drying, crushing and screening, using alkali soluble and acid sinking process to purificate the alkali lignin, the processed of purified lignin using ionic liquid [BMIm] Cl to replace the traditional organic solvents and dissolving for 2 h under 70℃, then using H2O2 as oxidant to oxidative modification of dissolved lignin, oxidation time is 2 h, oxidation temperature of 80℃,oxidation of lignin (OLG).Second, OLG as raw material, with reference to the synthesis principle of bisphenol A type epoxy resin,use the OLG and epichlorohydrin (ECH) in alkaline conditions having epoxidation reaction, getting the lignin-epoxy resin (LGEP),the FT-IR infrared characterization analysis showed that LG and ECH having the epoxidation reaction successfully.Design four factors three levels orthogonal experiment using epoxy value for the response, the using of ECH, the PH of the reaction solution, reaction time and reaction temperature are the four factors influence on epoxidation reaction, to explore the best synthesis process, get the best synthesis condition are:m (ECH):m(OLG)= 6:1, PH= 9, reaction temperature 115℃,reaction time 6h, on this condition getting the epoxidation reaction generated LGEP epoxy value is 0.363.On the basis of the process conditions, setting single factor experiments on synthesis LGEP to determine the performance of other items, measured bibulous rate is 0.472, viscosity 6.63P, solid content is 51%.Finally, using LGEP for curing reaction, curing process using phthalic anhydride as curing agent, promoter triethylamine, establish autocatalytic reaction model to simulate the solidification process of dynamic analysis, based on the best curing temperature LGEP curing kinetics equation is obtained for T=502.52 K, obtained under the conditions, when the curing degree a= 95%, the curing time T= 62.85 min.Curing degree a= 99%, the curing time t=154.66min.