The Effect Of Alkali Combined With Enzyme Treatment On The Separation Process Of Cellulose, Hemicelluloses And Lignin Of Poplar Wood And Cellulose Micro/nano Fibrils

In this thesis, the poplar wood was selected as research objects. Alkaline treatmentand enzyme treatment were used to deal with the poplar. At each step, we studied the influenceof alkali treatment and enzyme treatment on the separation process of cellulose, hemicellulosesand lignin. Crystallinity, particle size and thermal performance of the polarfiber were analyzed toconcluded four points as following.(1) By the analysis of response surface,the optimal conditions of alcohol and alkalinetreatment were5%concentration,83℃and8h.There is interaction between factors.After thetreatment,the removal rate of lignin is69.6%. Considering the H₂O₂treatment effect, the optimalconditions of extract hemicellulose is85℃,3h and pH8-10.(2)Filter paper enzyme activity is72.8FPU/g and xylanase activity is15.6IU/g. Throughanalyses of the hydrolysis rate of cellulose and hemicelluloses in35h,we choose filter paperenzyme activity is12FPU/g(substrate). Crystallinity of polar fiber was improved after enzymetreatment.(3) On the basis of alkali and enzyme treatment,the best conditions of ultrasonic treatmentwere Solid-liquid ratio10:1,20min and80μm amplitude.Particle size analysis and SEMpicture analysis showed that particle size had met the requirement and micro-nano fibrils hadgood dispersion.(4) Phenolic resin with micro-nano fibrils and phenolic resin without micro-nano fibrilswere both calculated the activation energy.The results shows that phenolic resin withmicro-nano fibrils is149.9kJ/mol,which is lower than phenolic resin without micro-nano.Sophenolic resin with micro-nano fibrils is easier to reaction.Besides,when the addition ofmicro-nano fibrils reached1.5%,the phenolic resin has the best bonding strength.The bondingstrength of phenolic resin was improved in different temperature and preesure wirh the additionof micro/nano fibrils.