Obtaining of microcrystalline cellulose from hardwood pulp | Mikrokristāliskās celulozes iegūšana no lapu koksnes celulozes
2009
Laka, M., Latvian State Inst. of Wood Chemistry, Riga (Latvia) | Cernavska, S., Latvian State Inst. of Wood Chemistry, Riga (Latvia)
Microcrystalline cellulose (MCC) is currently widely used in different industrial fields. In the powder form, it is used as additive and binder in the production of medical and food tablets, in compact powder, etc. In the gel form, it is used as suspension stabiliser, emulsifier and viscosity regulator in various pastes, creams, etc. The aim of the present work was to develop a technology for obtaining MCC from *hardwood pulp by the thermocatalytic method. As a raw material, bleached birch and aspen wood sulphate pulp (Finland) was used. Thermocatalytic treatment conditions for reaching the levelling-off degree of polymerisation of cellulose, when the amorphous part is destructed, but the crystalline one remains practically intact, were developed. For this purpose, pulp samples were impregnated with hydrochloric acid solutions of different concentration and dried at elevated temperatures. With increasing hydrochloric acid concentration and thermal treatment temperature, the degree of polymerisation of cellulose at first decreased dramatically, and then reached a constant value - the levelling-off degree of polymerisation (LODP). In the case of birch wood pulp and aspen wood pulp, it was 450 and 370, respectively. From the obtained results, the following thermocatalytic treatment conditions were determined: hydrochloric acid concentration 0.025-0.050%, thermal treatment temperature 90-120 deg C, standing time in the hydrochloric acid solution 2 h.
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