Some aspects of the rheology of adhesives and wood

Abstract

After briefly mentioning the important role played by rheology in the study and use of wood and adhesives, work done on the subject in the author's laboratory is briefly described. From a study of the rheological changes taking place in casein glues with the help of a Couette viscometer a possible mechanism of gel formation is presented. The influence of various factors on gel formation were also studied with interesting results. For following the course of setting of adhesives the method using the wire resistance strain gauge was employed and the influence of temperature and humidity on the setting time investigated. The rigidity modulus of gelatin gels measured with a Saunders and Ward apparatus was found to vary as the square of the concentration. Sodium chloride increased the rigidity. Rheological properties of adhesive films of gelatin, casein and prolamin were studied under a wide variety of conditions with the torsion pendulum and the interesting results reported. Interesting results were also obtained on the rheological properties of wood and the influence of extractives, acids, alkali, etc. on such properties. Finally plastic flow in wood with loading was investigated.