NEW APPROACH TO THE DESCRIPTION OF YOUNG MODULUS FOR HIGHLY ORIENTED POLYMERS .2. RELATIONSHIP BETWEEN YOUNG MODULUS AND THERMAL-EXPANSION OF POLYMERS OVER A WIDE TEMPERATURE-RANGE

An empirical equation for Young's modulus is proposed. It originates from thermal fluctuations and relates Young's modulus for highly oriented polymers, E, to thermal expansion strain of the segments of macromolecular helices, epsilon(T), and to measurement time tau: E = E0 (1 - kepsilon(T)/C0epsilon* ln tau/tau0) where E0 is the E value at epsilon(T) --> 0, C0 is the heat capacity, k is the Boltzmann constant, epsilon* is-approximately-equal-to 0.1, and tau0 = (10(-12)-10(-14))s. The equation may be used for description of the temperature dependences of Young's modulus, E(7), at tau = constant over a wide temperature range: from cryogenic to melting temperatures. It was shown that complicated (nonlinear) E(T) dependences were due to the variability of the epsilon(T)(T) function because of the substitution of the Boltzmann statistics for the Bose one for both torsional and bending vibrational modes in a polymer solid.