The Preparation And Performance Of Modified Cellulose Membranes Using NMMO As Solvent

As naturally occurring polymers, cellulose has the characteristics of abundant source,stable chemistry property and good filming property, so it can be used in the fields of packing,medical, battery and so on. However, the shortage of its mechanical property and bad thermalstability limit its application. In this study, we prepared blend membranes to improve itsproperties, the contents are as follow:Firstly, we study the effect of the cellulose species and cellulose concentrations on themechanical properties of the membranes. The results showed that when the celluloseconcentrations is between4percent and10percent, the reed cellulose present goodfilm-forming. In addition, regardless of which cellulose species is, the membranes with eightpercent cellulose concentrations present better mechanical properties, and the cotton cellulosemembranes presented the best of all.Secondly, we study the effect of wood cellulose and cotton cellulose concentrations,glycerol volume fraction and dried ways on the membranes’ properties. The results showedthat the best way to prepare the wood cotton cellulose blended membranes is as follow:thewood cellulose and cotton cellulose concentrations is20:80, glycerol volume fraction is30percent, and the dried way is firstly dried at35℃and then55℃, finally75℃invacuum dryingoven. Under these conditions, the membranes are smooth and dense, and its tensile strength,elongation and transmittance can be reached2.61MPa,63.6%and13.7%, respectively. Inaddition, the Fourier transform Infrared spectrometry (FTIR) and XRD showed that thecellulose changed from cellulose Ⅰ to celluloseⅡ.Thirdly, we study the modification effect of different modification agent on the SiO2bytesting their hydrophobic and lipophilicity, and the modification agent are3-aminopropyltriethoxysilane (KH-550), anate coupling agent NDZ-201and stearic acid. Theresults found that the modification effect of KH-550is the best of all, therefore, in thispaper,we chose it as the modification agent for the SiO2. The FTIR and TEM indicated thatthe SiO2were successfully grafted with amino groups and well dispersed.Fourthly, we study the effect of additive and modifier concentrations on the blendedmembranes by testing their mechanical property, transmittance and water vapor permeability,the results showed that the membranes with0.5%unmodified SiO2presented littleimprovement, but still poor. However, the membranes with1.5%modified SiO2presentedperfect improvement, its tensile strength improved from1.82MPa to3.2MPa. In addition, itsthermostability improved greatly.