The Viscosity of Latex and of Latex Mixtures

Abstract For the rubber technologist, a change in the plasticity of rubber mixtures is one of the most important indications that fundamental changes are taking place within the mixture. For example, a decrease in plasticity would lead to the conclusion that incipient vulcanization had taken place, and an increase in plasticity would indicate degradation resulting from unfavorable conditions of storage, from the action of deleterious substances in the rubber, etc. Corresponding to these increases and decreases in plasticity in the case of dry rubber mixtures, increases or decreases in the viscosity of rubber solutions are found. These changes in viscosity and plasticity unquestionably conform to the facts which are now known about rubber and its behavior on degradation and on vulcanization. Further, latex, which is becoming of increasing importance, and mixtures prepared from it, undergo changes in viscosity on standing as well as during the processes of manufacture. There are many of these changes in the viscosity of latex, and accordingly it is much more difficult to ascertain them individually than it is in the case of solutions in organic solvents. It might be of importance to know more about the factors which influence the viscosity of latex. Then again in studying the viscosity of latex a great number of phenomena and problems are encountered which require explanation, so that a report of all the observations made during our investigation may be found of general interest.