Abstract
The study on frequency-dependence of mechanical properties of polymers is well recognized to be of both practical and theoretical values, but few methods of observing the dependence in the frequency range of 1 to 20 c/s have been reported. An apparatus incorporating a forced vibration torsion pendulum has been devised by the author for the measurement of dynamic rigidity and viscosity of polymer films within the above frequency range. For obtaining better accuracy con-cerning the frequency, electronic counter is introduced into the measuring circuit. The resonance method is adopted, for the frequency-amplitude curve was very sharp. The apparatus and the method of calculation are explained in detail, and the accuracy of obtained data is examined. Results of measurement made on some coating films are given as examples.
Experimental errors in measuring the rigidity of coating films that have a small loss tan δ (ca. 0.01) were 10_??_15 percent and those on the viscosity were 10_??_20 percent. The date thereby obtained were free from the effect of the load that hung at the lower end of the sample film.
