Molecular weight cellulose

Solutions of cellulose in NH3/NH4SCN (27 73 w/w) are liquid crystalline at concentrations from 10-16% (w/w) depending on the cellulose molecular weight (64). Optical rotations of the solutions indicate the mesophase is cholesteric with a left-handed twist. The solvent does not react with cellulose. Recently, Yang (60) foimd that cellulose (D.P. 210) formed a mesophase at 3.5% (w/w) concentration at a NH3/NH4SCN of 30 70 (w/w). 

Origin of cellulose Molecular weight Degree of polymerization Author... 

In the pulp eind paper industry, GPC has been applied not only in measuring cellulose molecular weights and MWDs, but also in following its degradation as a consequence of various pulping, bleaching and viscose processes. In the initial applications of... 

The M.S. of a hydroxypropyl cellulose sample is 3.5. The D.P. of the cellulose used to prepare the sample was 120. Calculate the cellulose molecular weight and the grams of propylene oxide used in the synthesis. Assume the average number of hydroxypropyl units per side chain is 5. Calculate the D.S. 

The resultant alkali cellulose is pressed to remove most of the excess NaOH solution and is shredded to increase the surface area and make the material easier to process. The shredded alkali cellulose is pre-aged with the presence of oxygen in the ambient air to reduce and control the cellulose molecular weight. After reaching the desired molecular weight, carbon disulfide (CS ) is added to the shredded alkali cellulose in a specially designed vessel called a Barette at 20-30°C for 1-3 hours to cany out the xanthation step, which leads to the formation of sodium cellulose xanthate. The following is the main reaction in the xanthation step ... 

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