Study On Preparation Of Cellulose Sol

Cellulose is one of the most abundant macromolecular compounds of the nature,which has the advantages of green, environmental protection, renewable. With the dwindling energy of the global, cellulose, which as a renewable energy source,was concerned by all of countries. However,the cellulose has molecular weight,readily soluble in common solvents, strength inter molecular hydrogen bond,difficultly to decompose,these features hinder its apply research. In the present study, sodium hydroxide/urea solution,copper-ammonia solution,zinc chloride aqueous solution, these three different solvents were used to dissolve the microcrystalline cellulose,and then regenerated for cellulose sol, also acrylic acid was used to graft cellulose,then regenerated for cellulose sol.Cellulose was dissolved by7%NaOH/12%urea solution (NaOH/CH4N2O), copper ammonia solution,65%of the zinc chloride/aqueous solution (ZnCl2/water),the solubility of the three different solvents to MCC and the characteristic of the regenerated cellulose sol were studied. It was showed that under certain experimental conditions all of the three different solvents capable of dissolving the microcrystalline cellulose to form a transparent solution, the solubility of MCC in the65%zinc chloride/aqueous solution at room temperature up to3%.The malvern analyzer test results showed that the direct regeneration cellulose suspension has long particle size and poor stability. While the particle size of cellulose sol was reduced by adding sodium carboxymethyl cellulose (RnOCH2COONa) to help SC, with the lower concentration of regenerated cellulose the suspension particle size showed a decreasing trend. The regenerated cellulose sol was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermal analyzer (TG), scanning electron microscopy (SEM) analysis. Compared with MCC,the regenerated cellulose sol has a smaller crystallinity,weakener intermolecular hydrogen bonds,lower thermal decomposition temperature.The homogeneous graft copolymerization of acrylic acid (AA) onto MCC with potassium Persulfate as an initiator and wt65%zinc chloride aqueous solution as a reaction medium was studied. The effects of reaction conditions such as initiator charge, initiate time, reaction time, monomer concentration on the graft yield and graft efficiency were investigated. The graft copolymer was characterized by FTIR,XRD and TGA analytical techniques.The results showed that when the mass ratio of initiator to cellulose was1:2, the monomer to cellulose was5:1, the initiate time was10minutes, the reaction time was8h, the reaction temperature was60℃, the graft yield could reach20.3%.With the increase of grafting time the size of the grafted copolymer showed an decreasing trend while the potential showed an increasing trend.The results which proved that the acrylic acid grafted onto MCC was the graft copolymer has the absorption peak at1729cm-1. The graft copolymer had the similar chemical and crystal structure as MCC, whlie the crystallinity was smaller after grafting. Compared with MCC, the graft copolymer had a lower thermal decomposition temperature.