Synthesis And Characterize Of Cellulose Acrylate Liquid Crystal

Cellulose and many of cellulose derivatives can form liquid crystals under special condition. The cellulose acrylate(CEA) was prepared by acylate reaction with cellulose as raw material and acryloyl chloride as acylate reagent in homogenous reaction system. In this work, the investigation including: the dissolution of cellulose, the synthesis of cellulose acrylate, characterize cellulose acrylate constructure, surface performance and liquid crystal t al.The ingredients that effect the formation of cellulose homogeneous solution was investigated, and the ingredients including: activation reagent, activation time and temperature, the concentration of LiCl in DMAC, dissolution temperature and time. The result indicated the favourable conditions about activation of cellulose were the cellulose was crush up to 120 mesh, immerged in 20% NaOH water solution at 20～30℃for 1h. Then droped watery HCl in the activation cellulose until neutralization, filtrated, washed by methanol and N, N-DMAc, then dryed under 80℃. The better condition of the formation of cellulose homogeneous solution were the concentration of lithium chloride(LiCl) was 5-10%, and the concentration increase with the concentration of cellulose in N, N-dimethylacetamide(DMAc), stired for 1h at 150℃, then decrease the temperature to 120℃, and stired for 0.5h, laying until the solution was clear clarity.The influence of reaction temperature, and reaction time, and acylation dosage as well as the percentage of cellulose to degree of substitution of the products were investigated. The results showed that the favourable acylate reaction conditions of acryloyl chloride and cellulose were the reaction temperature at 50℃, and the reaction time at 3.5h, and the mole ratio of the acylation dosage to the hydroxyl of cellulose taking 3.35, and the concentration of cellulose using 1.95%. The produce was air-dried and kept at 65℃under vacuum, until constant weight.The chemical structures and the degree of substitute of products were characterized by FTIR, elemental analysis and ¹3C solid state NMR spectroscopy, Crystallinity index was determined by X-ray diffraction, the thermal stabilities of cellose and cellulose acrylate were evaluated using thermogravimetric analysis (TGA). The thermal stability of acylate cellulose lower than that of cellulose. Thermal properties of cellulose acrylate was studied by differential scanning calorimetry(DSC), the curves showed that the cellulose acrylate has't the glass transition temperature. The liquid crystalline behavior of cellulose and cellulose acrylate was studied by Polarizedoptical microscopy(POM), it was found that the powder of them did't show thermotropic liquide crystalline behaviour and the cuvers of DSC can also prove this. The cellulose (5%wt) homogeneous solution could't show liquid crystal, but it formed a liquid crystalline state when it was heated up to 100℃and the state can retain during the temperature falling. The solution cellulose acrylate in 2.0mol/L NaOH showed the same phenomena as cellulose solution. The optical texture suggests tha the liquid cryatalline phase is probably nematic and mesogenic liquid crystals.Inverse gas chromatography (IGC) is a sensitive conventient method to obtain important parameters. In this work the Flory-Huggins thermodynamic interaction parameters, X^∞₁₂, between CEA and solvents and the solubility parameter of polymers were caculated. The solubility parameter of cellulose are 22.03,22.08,22.0,22.26 and 22.36(MPa)^1/2 respectively at 50,55,60,65 and 70℃, the value is the summation of d_d and d_p. The solubility parameters of CEA are the summation of d_d, d_p and d_h, and the values are 26. 73,26.97,27.37 and 27.78(MPa)^1/2 at 40,45,50 and 55℃. The solubility parameters of cellulose and CEA increased with the increase of temperature. The solubility parqameter of CEA is smaller than that of cellulose. The reason was that the hydrogen of glucose was substituted by acryl, the distance between molecules increased and the hydrogen bond interaction between intermolecular and intramolecular declined.