Page 203 - Academic Press Encyclopedia of Physical Science and Technology 3rd Polymer

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Encyclopedia of Physical Science and Technology EN012c-598 July 26, 2001 15:59

712 Polymers, Mechanical Behavior

FIGURE 17 Dynamic mechanical behavior and respective parameters for (a) polyacetaldehyde, (b) polyvinylidene
chloride, and (c) conventional or atactic polymethyl methacrylate (dashed curves) along with its high isotactic configu-
ration (solid curve). [Reprinted with permission from McCrumb, N. G., Reed, B. G., and Williams, G. (1967). “Anelastic
and Dielectric Effects in Polymeric Solids,” Wiley, New York. Copyright 1967 John Wiley and Sons.]

due to the obvious decrease in modulus but that this drop Addressing the temperature dependence in Figs. 17a–c
varies in terms of its temperature dependence, as pointed we realize that, below the glass transition temperature,
out earlier in the discussion of the thermal mechanical modulus is only slightly dependent on the temperature
spectrum. because there is insufficient thermal energy for the overall