Fracture of Amorphous Polymers

Abstract At sufficiently high temperatures compared to the glass temperature, both experimental evidence (Figure 7) and Equation (10) predict that failure envelopes obtained from samples differing in νe will superpose to a common response curve f(e) independent of chemical structure of the polymer when σb is normalized to unit νeT. At lower temperatures, experiment and Equation (8) indicate that in such a normalized plot, individual failure envelopes will diverge from the common response curve, f(e), due primarily to the effect of the chain flexibility parameter n. As the temperature is lowered still further, Equation (6) shows that the shapes of individual envelopes may vary if the time dependences of E and g differ. This effect is presumably the factor which produces the difference in shapes between the Viton elastomers and the others shown in Figure 7. In addition, Equation (4) relates the maximum value which λb can attain to other readily measured parameters, notably νe. Thus knowledge of these two pa...