Application of Deoxyaminocellulose to a Flocculant

Abstract

Soluble deoxyaminocelluloses (DACs) with degree of substitution, DS(NH₂), up to 0.64 were prepared by the nucleophilic substitution of soluble deoxycellulose p-toluenesulfonates, DCTs, which had prepared from dissolving pulp and powdered cellulose dissolved in LiCl/N, N-dimethylacetamide system, with ammonia in dimethylsulfoxide. Compared with DCT prepared from powdered cellulose, that from dissolving pulp needed long reaction time and high temperature to obtain soluble DACs, and obtained DACs showed high yield, high DS(NH₂) and high intrinsic viscosity, [η]. Ability of the DACs added to bentonite aqueos suspension as a flocculant was examined and found that settling rate of the yielded flocs showed a maximum in respect to the amount of DAC added and the maximum settling rate was higher at higher [η] of DAC. The filtration rate of the flocculated suspension and the transparency of the filtrate were higher at more amount of DAC and at higher [η] of it. The settling rate found in the examination using DAC with the heighest [η] was almost comparable to that found for chitosan. From these results, it may be concluded that dissolving pulp is more advantageous than powdered cellulose for preparation of DAC as a flocculant, and that DAC is useful as a flocculant like chitosan, in spite of its lower [η] than that of chitosan.