Five samples of triphenylsilyl cellulose (TPSC) are characterized in solution by osmometry, viscometry, and size exclusion chromatography. The isolated and purified cellulose ethers are prepared in a N,N-dimethylformamide and pyridine medium under heterogeneous starting conditions and a nitrogen atmosphere by silylation of activated celluloses with triphenylchlorosilane at 115-120 degrees C. TPSCs are characterized by their polydispersities and degrees of substitution by osmometry and viscometry in various solvents. The Mark-Houwink-Sakurada equation coefficients are evaluated in 1,1,1-trichloroethane, chloroform, and o-xylene at 30 degrees C and in o-xylene over a temperature range of 30-70 degrees C. Values of 2.12-2.18 are obtained for exponent a. This indicates, in combination with low values of the preexponential factor (on the order of 10(-12)), strong stiffness of the macromolecular chains. (c) 2006 Wiley Periodicals, Inc.