Analysis And Application Products Of Green Hydrolytic Of Cellulose And Chitin

Modrnm societies existed in a variety of global crises such as food,energy and resource shortages,environmental and ecological damage.In order to solve this global crisis,we have done some research.Two kinds of widely selected,natural non-toxic,biocompatible,easy to degrade and widely used cellulose and chitin were selected.This paper was divided into three chapters.The first study is through the hydrogen peroxide to convert cellulose into polysaccharides and its derivatives,the study condition is the reaction temperature and reaction time.This study was divided into two parts,on one hand is mechanical pretreatment,and on the other hand is H2O2 oxidation hydrolysis.Secondly,the oxidative hydrolysis of chitin was studied.The method was similar to the preparation of cellulose nanocrystals.Before the combination,the performance and structure of chitin nanocrystals were deduced.The effects of different oxidative degradation conditions on the obtained chitin polysaccharide were studied.Including the ratio of H2O2-chitin nanocrystals(CHNs)(100-300 mL/g),different oxidation degradation times(12-60 h)and different reaction temperatures(50-90 ?).Finally,the graphene oxide(GO)obtained by the Hummers method was absorbed by cellulose and chitin nanocrystals and fibers prepared by different methods.The results showed that the Zeta size(624.3-91.3 nm)and the yield of CNCs(43.6%-0.2%)decreased with the increase of reaction temperature and reaction time under H2O2:MFC = 100 mL/g.At the same time H2O2 hydrolysis of cellulose nanocrystals(CNCs)has a relatively low Zeta potential of about-20 mV.The nanocrystals measured by 13C CP/MAS NMR had three distinct peaks,namely the hemiacetal bond,the benzyl ring and the carboxyl group.At the same time,the FTIR results also indicate the presence of carboxyl groups.The optimum reaction conditions were H2O2:CNF = 200 mL/g,the reaction temperature and the reaction time was 70 ? and 24 h,respectively.The Zeta size was 342.1 run and the Zeta potential was-13.25 mV,the yield of chitin nanocrystals was 2.64%.The main products obtained by H2O2 oxidation and hydrolysis were tested by a rapid,sensitive and accurate UPLC-MS/MS technique.The results indicated the presence of a complete degradation to produce a series of monosaccharides,disaccharides,polysaccharides and their derivatives.The adsorption of GO with the nanocrystals was characterized by UV,AFM and XRD.The results showed that the adsorption effect of chitin nanocrystals was demonstrated by hydrochloric acid hydrolysis.The best and greatest reason is that the zeta potential of chitin nanocrystals obtained by hydrolysis with hydrochloric acid is positive and attracts negatively with the negative potential of GO,resulting in a relatively easy adsorption effect.The best feature of this paper was that the preparation process is environmentally friendly,non-polluting and no other harmful by-products.The products obtained during the adsorption process can be applied to the subsequent spinning process without causing any pollution and environmental protection effect.