ジャガイモデンプンのレオロジー的研究(第5報) : デンプンホルムアミド溶液の動的粘弾性

概要

論文の詳細を見る
The dynamic modulus G and viscosity ηd of potato starch solutions in formamide were measured in a concentration of 2.0g/100ml by using a forced torsional vibration rheometer under the condition of various frequencies and temperatures. It was found that the solution was thermo-rheologically simple; the master curves of the dynamic modulus and viscosity as a function of frequency were composed by means of the time-temperature reduction principle. Temperature dependence of the shift factor aT, the apparent activation energy_??_Ha, the zero shear intrinsic viscosity [η]_??_→0 and the relaxation spectrum were also investigated. Taking the temperature of 30°C as reference state, the relaxation spectrum appeared as nearly linear with the gradient of -0.86, ranging from 0.41 down to -2.17 (dyn/cm2) of the relaxation spectrum log H (τ), between -0.19 and 2.79 (sec.) of the relaxation time log τ. When the same methods were applied to the solution of γ-ray irradiated potato starch, which was used expediently as a lower average molecular weight starch, the relaxation spectrum was shifted to the shorter relaxation time than the unirradiated case. As to the relations between the relaxation spectrum and [η]_??_→0, it was found that the decrease in [η]_??_→0 corresponds to the shift of the relaxation spectrum to the shorter relaxation time.
社団法人日本農芸化学会の論文