Synthesis Of Imidazolium Ionic Liquids, Solubility For Cellulose And Wood And Its Application For Polymer

A series of imidazolium ionic liquids were synthesized and their solubilities for cellulose and fir powder were discussed; Modified flocculants were prepared by grafting dissolved cellulose or fir powder with acrylamide (AM) in ionic liquids and the flocculations for waste water were studied. Besides, ionic liquid/fir powder/phenol-formaldehyde composite adhesive was prepared in situ and the effects of the ionic liquids and fir powder on the performance of the composite adhesive were researched.The main contents as follows:1. A series of imidazolium ionic liquids, [BMIM]Cl, [AMIM]Cl, [HeMIM]Cl, [AEIM]Cl, [HeEIM]Cl and [HeVIM]Cl, were synthesized using N-methyl imidazolium, N-ethyl imidazolium, N-ethylene imidazolium, allyl chloride and chloroethanol as raw materials, and chemical structures of the ionic liquids were characterized by FTIR and 1H NMR. The side chains had great effects on ionic liquids'physical properties. The longer side chain of the ionic liquid was, the greater was its viscosity and the smaller was its conductance rate and surface tension. Ionic liquids containing double bond on its side chain had a higher conductance rate, while the ionic liquids containing hydroxyl group had a higher surface tension. It was shown that the ionic liquids had higher density, viscosity, boiling point and lower surface tension compared with water or organic solvents.2. Cellulose and fir powder were pretreated with different concentrations of NaOH under various technologies (normal temperature and pressure, microwave and high pressure pot) respectively. Hydrogen bonding actions of cellulose and fir powder were all weakened greatly after treatment and the crystallinity of them were also decreased. The most effective concentrations of NaOH were 30%, 15% and 25% to dip cotton fibre, microcrystalline (MCC) and fir powder respectively in the high pressure pot (140℃). Degree of polymerization (DP) of cotton fibre after treatment was decreased from 1180 to 632 and crystallinity was changed from 82.6% to 53.3%, DP of MCC was decreased from 306 to 153 and crystallinity was changed from 92% to 49.2%, relative crystallinity of fir powder was degreased from 61.0% to 2.4%.3. Cellulose and fir powder after treatment were dissolved in ionic liquids by microwave heating and traditional heating. The solubilities of the ionic liquids were studied, the effects of dissolving methods and temperatures on dissolving rate of cellulose were discussed. Intermediate of ionic liquid with carbonyl group was synthesized with thionyl chloride, N-ethyl imidazolium and chloroacetic acid, and then reacted with cellulose to prepare ionization cellulose ester, whose solubility was also examined. The soluble effect of microwave heating was far superior to traditional heating, and the most suitable temperature was 90℃. The solubility of [HeVIM]Cl was best, crystallinity and thermostability of regenerated cellulose and fir powder residue after dissolved were decreased and morphology of them was changed greatly. Compared with ionic liquids, ionization cellulose ester had better solubility for cellulose due to its strong degradation of cellulose.4. Modified flocculants were prepared in ionic liquids by grafting AM onto MCC or fir powder, which were dissolved by microwave heating at first. The flocculations of the flocculants were studied by treating with coal slurry water and argil waste water. The performances of the flocculants prepared in ionic liquid were far superior to aqueous medium. The performance of cellulose flocculant (AM-g-MCC) was best when the polymerization temperature was 45℃and the mass ratio of ionic liquid to MCC was 25:1. While the performance of wood flocculant (AM-g-Wood) was best when the mass fraction of AM was 25%, the mass ratio of ionic liquid to fir powder was 30:1 and the mass ratio of wood to AM was 1:4. Both cellulose flocculants and wood flocculant had good flocculations, the wood flocculant was more suitable for treating with tiny particles of argil waste water.5. Fir powder was dissolved in ionic liquids by microwave heating (400w, 90℃) at first, then reacted with phenol and formaldehyde to prepare ionic liquid/fir powder/phenol-formaldehyde composite adhesive. Effects of fir powder and ionic liquids on performances of the adhesive were studied. The performance of the adhesive prepared by ionic liquid with hydroxyl was best, free formaldehyde of the adhesive decreased from 1.76% to 0.16% compared to common PF, the tensile shear strength increased from 2.16MPa to 8.38MPa when the mass ratio of [HeVIM]Cl to fir powder was 10:1. Besides, the tensile shear strength increased with the mass of ionic liquid increasing, and the cured composite adhesive had higher transparence and better luster, its thermal decomposition temperature was increased, while the content of residual carbon was decreased.