Dynamic Methods for Determination of Bond Strength between Rubbers and between Rubber and Cord

Abstract

Abstract The standard methods of determination of bond strength between layers of rubber and rubberized fabric and between rubber and other materials (GOST 6768-53, GOST 264-53 and others) are of the static type and do not give a clear assessment of the bond strength of multiply rubber structures which are subject during use to temperature influences and to complex deformations which are repeated many times. This drawback is partially compensated for by carrying out the tests at elevated temperatures. Nevertheless static tests, from their very nature, cannot reproduce the particular character of dynamic conditions. In recent years there have been developed in different countries a large number of dynamic methods of determination of bond strength, which often differ little from each other in principle. In connection with the establishment of production of tires of 100% synthetic rubber, and also the introduction of viscose cord, dynamic methods were established in the Nauchno-Issled. Inst. Shin. Prom. (Tire Research Institute) and at the Moscow and Yaroslavl Tire Works. These methods differ from each other in the nature of the action (repeated compression, repeated shear and the like) and in the shape, structure and dimensions of the specimens being tested, but were fairly similar in the testing routine. If the settling of the specimens in the testing period is negligible, then the testing routine may be regarded as one of constant dynamic deformation, or, more accurately, of constant ampliture of movement of the platens deforming the specimens. In 1954 we established in the mechanical testing laboratory of the Nauchno-Issled. Inst. Shin. Prom. a new method of determination of the bond strength of the rubber with rubber and of the rubber with the cord. The method allows tests to be carried out in repeated compression and in repeated shear in three principal sinusoidal cycles: 1) with constant dynamic loading, 2) with constant dynamic deformation and 3) with constant product of amplitudes of force and movement.