Polysaccharides viscometry

The effect of heat on the polysaccharide-water interaction in several dispersions and suspensions was studied by comparative viscometry and rheometry (Tables I-IV). The polysaccharides were the purest manufacturers grade laboratory washed and dried before dispersion. The dispersion concentrations were below c to accommodate capillary viscometry, and the suspension concentrations were above c to accommodate rheometry. It is seen in Tables I and II that the cellulose derivatives made the most stable dispersions and the propylene glycol alginate made the least. Dispersions of the neutral polysaccharides were more stable than those of the ionic polysaccharides. From Tables III and IV, it can be argued that suspensions benefit... 

Figure 6 suggests that the viscosity of ionic polysaccharides in dilute d-tartaric acid (TA) and of nonionic polysaccharides in water (c, = 0.05-0.07%) are in the same general t),- — ci orbit at 28°C. A sample of CMC (0.05 g) was dispersed in 80-mL water in 100-mL beakers to which TA was afterward added to different molarities TA supplied the H+ counterion intrinsic to an ionic polysaccharide and the nonintrusive tartrate ion. The solutions were transferred to 100-mL Erlenmeyer flasks and brought to volume with water prior to dilution viscometry. Judging from Fig. 7, a molar concentration of TA approximating 0.35 ensures an r sp/ci minimum in a dilute CMC dispersion (ci = 0.05-0.07%). 

The DP of y-irradiated cellulose, as measured by viscometry in cuprammonium solution, has been shown to be lower than that of the untreated cellulose. Irradiation not only induced direct scission of the polysaccharide chains but also the formation of alkali-labile groups, which subsequently underwent scission in the solvent used for viscometry. 

Takashi Norisuye received his PhD degree in polymer science from Osaka University, Osaka, japan, in 1973. Two years earlier than this, he actually started his tenure work on polymer science as Assistant Professor at the Department of Polymer Science (currently, the Department of Maaomolecular Science), Osaka University. He was promote to associate professor and professor ofthe same department in 1986 and 1996, respectively, and retired in 2007. He is now Emeritus Professor of Osaka Univeisity. Throughout his scientific carrier, he worked on solution properties of macromol niles both theoretically and experimentally with particular interest in excluded-volume effects, helix-coil transition in polypeptides, stiff or rigid chains, polysaccharides, and polyelectrolytes. For those experimental studies, he used sudi t diniques as light and SAlffi, ultracentrifugation, osmometry, polarimetry, NMR, and viscometry. 

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