Study On Influencing Factors Of Alkaline Degradation Reaction Of Cellulose

Cellulose is the main plant fiber material of pulp. During pulp making process, cellulose degradation may occur in alkaline solution then the strength of the pulp decreased. In this experimental except reaction time, reaction temperature, dosage of NaOH, the effect of Mg2+and K+which represent the alkali metal and alkaline earth metal ions on the degradation ofcellulose will be researched also.In this study, microcrystalline cellulose (MCC) selected as the model compound of cellulose to react. Examined reducing sugar by UV spectrophotometer and changed in MCC by infrared spectra to response the effect of various factors on the reaction. Then select the cotton fiber as cellulose reactant to investigate cellulose’s changes of basic quality, average degree of polymerization, reaction activation energy and glucose in different condition. Experiments the following conclusions.The degradation of MCC not reacted strongly untill the temperature get80℃. The degradation amount of MCC changed little when the alkali was more than20%. Analysized by IR absorption, after reaction the MCC which adding Mg2+compared with blank samples, cellulose intramolecular hydrogen bond and inter molecular hydrogen bond of cellulose ruptured,β-2glycosidic bond ruptured more than blank. Compared with the blank sample by adding K+in the degradation of MCC, intermolecular hydrogen bond of cellulose ruptured less than the blank, the content of P-2glycosidic increased.Cotton fiber was selected as the cellulose reactant to investigate the effect of different condition on the alkaline degradation ofcellulose. In the same condition, compared with the average polymerization degree of blank cellulose, the average polymerization degree of cellulose which added K+was more and which added Mg2+was less. By comparing the reaction rate constant and the reaction activation energy, we obtained that the reaction which added K+promoted the degradation of cellulose accelerated and the reaction was easier to conduct relatively than the blank, but Mg2+get the opposite effect.The glucose content of blank was0.8558g/L detected by HPLC, while adding Mg2+the glucose was0.6378g/L and adding K+the glucose was1.5010g/L. These showed that Mg2+inhibited alkaline degradation of cellulose and K+promoted.