Effect of electrolytes on the rheological properties of microcrystalline cellulose gels

• Autorzy: Laka M. , Chernyavskaya S. , Faitelson L. , Jakobsons E.
• Konferencja: Second International Conference on Engineering Rheology ICER 2003
• Języki publikacji: EN

Abstrakty

EN

The rheological properties of microcrystalline cellulose (MCC) gels, obtained by dispersing in different electrolyte (salt, hydroxide, acid) solutions the wood pulp destructed to the levelling-off degree of polymerization were investigated. It has been found that, in all electrolyte solutions at the cellulose concentration ł 8%, MCC gels with rheological properties characteristic for liquid crystalline polymers are obtained. The values of the rheological characteristics depend on the chosen electrolyte. When dispersing the destructed pulp in salt solutions, the rheological indices are affected by the presence of both cations and anions in the solution. Cations promote gel formation, which results in obtaining of MCC gels with greater viscosity and yield stress, but the effect of anions is opposite. In hydroxide solutions, the values of the rheological indices (viscosity, yield stress) grow as the pH value increases, while, in acid solutions, they change little and tend to grow with decreasing the pH value. The connection of the obtained relationships with the effect of the investigated electrolytes on the z-potential of the cellulose particles present in MCC gels is considered.

Słowa kluczowe

EN

microcrystalline cellulose gels; electrolytes; viscosity; shear rate; yield stress

PL

elektrolity; lepkość; celuloza; plastyczność

• Wydawca: Oficyna Wydawnicza Uniwersytetu Zielonogórskiego
• Czasopismo: International Journal of Applied Mechanics and Engineering
• Rocznik: 2003
• Tom: Vol. 8, no spec.
• Strony: 265--269
• Opis fizyczny: Bibliogr. 6 poz., tab., wykr.

Twórcy

autor

Laka M.

• Latvian State Institute of Wood Chemistry, 27 Dzerbenes Str., LV-1006 Riga, LATVIA

autor

Chernyavskaya S.

• Latvian State Institute of Wood Chemistry, 27 Dzerbenes Str., LV-1006 Riga, LATVIA

autor

Faitelson L.

• Institute of Polymer Mechanics, Latvian University, 23 Aizkraukles Str. LV-1006 riga, LATVIA

autor

Jakobsons E.

• Institute of Polymer Mechanics, Latvian University, 23 Aizkraukles Str. LV-1006 riga, LATVIA

Bibliografia

• [1] Casson N. (1959): In: Rheology of Disperse Systems (C.C. Mili, Ed.). - New York: Pergamon Press.
• [2] Guido S. and Grizzuti N. (1995): Phase separation effects in the rheology of aqueous Solutions of hydroxypropylcellulose. - Rheologica Acta, vol.34, No.2, pp.137-146.
• [3] Laka M. and Chernyavskaya S. (1996): Method for obtaining microcrystalline cellulose. - Latvian Patent No. 11184.
• [4] Laka M., Chernyavskaya S., Faitelson L. and Jakobsons E. (1999): Rheological peculiarities of microcrystalline cellulose gels. - Applied Mechanics and Engineering, vol.4, Special Issue ICER’99, pp.351-355.
• [5] Laka M., Chernyavskaya S., Treimanis A. and Klavins Z. (2002): Effect of cations on the formation of MCC gels. - Proc. 7th European Workshop on Lignocellulosics and Pulp, Turku, August 26-29, 2002, pp.459-462.
• [6] Zeta potential measurements with the Zetamaster (1993): - Applying Advanced Particle Science in Industry and Research, Application Manual, Spring Lane South: Malvern Instruments Ltd.