Preparation And Application Of Cellulose Side Chain Liquid Crystals With Ionic Liquid As Solvent

Cellulose,as the most abundant and renewable resource in the world,has draw much attention of researchers.Viscose fiber and Lyocell fiber have been industrialized,but their spinning process along with environmental pollution and energy consumption.Ionic liquid,as a new solvent,has a strong ability to dissolve cellulose.The preparation of cellulose fibers by cellulose/ionic liquid has the advantages of environmental friendly and easy solvent recovery.However,the increase of cellulose concentration leads to the rapid increase of the viscosity of cellulose solution.In order to prepare cellulose solution with high concentration and low viscosity,cellulose liquid crystal system is proposed.In this study,we designed and synthesized a new type of cellulose side-chain mesoenic unit(CbP),studied the conditions of side-chain liquid crystal formation,prepared side-chain cellulose liquid crystal and studied its rheological and liquid-crystalline properties,and prepared cellulose fiber by dry-wet spinning.The specific research content is as follows:Turbidity test and Fourier-transform infrared spectra(FTIR)indicated that homogeneous solution of CbP/AMIMCl had been formed and there was no chemical reaction between CbP and AMIMC.The steady and dynamic shear measurements,polarized optical microscopy(POM),differential scanning calorimetry(DSC)and X-Ray diffractomer(XRD)were used to study on the rheological behaviors and phase transition of cellulose/CbP/AMIMCl system.The results showed that there was an obvious liquid crystal phenomenon in cellulose/CbP/AMIMCl when the mass fraction of CbP in AMIMCl is 2-4wt%,solution temperature is 40-80 ?.The deviations from COX-MERZ rules suggested that the destruction of intra-and intermolecular hydrogen bonds between cellulose,CbP and AMIMCl under shear deformation.Surface appearances and mechanical strength of fibers prepared by cellulose liquid crystal solution and cellulose solution were studied by scanning electron microscopy(SEM)and electronic single fiber strength meter.The results showed that the fibers diameter prepared by cellulose liquid crystal solution were more finer and mechanical strength increased by 34%than pure cellulose fibers.