Abstract
The dynamical Young’s moduli (E) and the internal friction \fracΔW2πW (ΔW: energy dissipation per cycle) of amorphous films of P.V.A. were observed under the various conditions. (1) Effect of temperature; E is almost constant at the room temperature, but it decreases rapidly beyond the characteristic temperature, which may be considered as the 2nd-order transition temperature, and it tends to the constant value at higher temperature. \fracΔW2πW increases gradually from the room temperature and saturates to the constant value at higher temperature. (2) Effect of humidity; E increases slightly up to R. H. 35% and beyond this point it decreases rapidly with increase of humidity, \fracΔW2πW is almost constant up to 25% but it increases rapidly beyond this point and tends to the constant value at higher degree of humidity. Besides, effects of tention, degree of polymerization and frequency were reported shortly. The experimental formula which represents the temperature dependence of E was devised and this formula also was suitable to the experimental results of P.V.C. The attempt to explain this formula from the statistical treatment of crystallite part and amorphous part was tried.
