Date of Award
Master of Science in Chemical Engineering - (M.S.)
Chemical Engineering and Chemistry
Leon Joseph Buteau
With the aid of a rotational viscometer, several transient phenomena were studied with different polymer solutions. In order to be acquainted with the operations of the rotational viscometer, viscosity measurements were made on polystyrene solution of a 7.14 wt. % NBS-2-35967 in a 35 - 65 mixture of aroclor and TCP, polyisobutylene (16.5% in mineral spirits), Indopol H-1900 (polyisobutylene) and 4.5% polyisobutylene in Primol 355. All these were done at a temperature of 77°F, except for Indopol H-1900 which was done at different temperatures. The results are listed in the section of tables and graphs.
Viscosity was measured with a rotational viscometer. Its operational mechanism will be described in the chapter dealing with experimental equipment. Next the properties of a 4.5% polyisobutylene in Primol 355 was exclusively investigated in terms of shear stress versus rate of shear, recoverable shear at infinite time versus shear stress, displacement or flow history versus time and recoverable shear versus time as a function of shear stress. Having obtained the curves of displacement versus time and recoverable shear versus time of a 4.5% PIB solution and the 3% PIB solution available from previous experiments at Esso Research Center, the shear velocity profiles of displacement versus time and irreversible shear versus time was investigated.
Recoverable shear (recoil measurements) was measured by a stop-load mechanism described in detail in later sections. Also investigated were a series of unpublished flow histories of a 3% PIB in Primol 355, beginning at time zero with the aid of a hi-speed camera. Having transformed the flow curves into shear curves, the phenomena in question being investigated is the existance of zero shear that occurs during the interval between .1 to .2 seconds for loads ranging between 5 and 500 grams. With the aid of a mathematical model and working in the area of complete elasticity, it was found that the zero shear is the result of two phenomena. These phenomena are the vibrations due to the string holding the weight and also due to the elasticity of the polymer solution. It was also found that the vibration due to the elastic property of the polymer solution had a very significant effect on the zero shear. The extent of that effect was also found to be a function of the load. The mathematical model used resulted in the following conclusion; the calculated inertial effects of the viscometer are much higher than the initially measured value, it predicts the zero shear phenomena, the spring constant for the polymer solution is a function of weight and it also gives an indication of the nature of the flow curves free of vibrational phenomena. The final results are graphs and tables describing viscosity measurements and transient phenomena occurring in the polymer solution.
Zwetkow, Nikolaus, "Transient phenomena of polymer solutions" (1975). Theses. 2173.