THE RELATIONSHIPS BETWEEN POLYMERS AND GLASS TRANSITION TEMPERATURES
Final summary rept. for Jun 1963-May 1965
AMERICAN CYANAMID CO STAMFORD CT
Pagination or Media Count:
A study of some empirical and theoretical functions for the effect of temperature on liquid viscosity indicated that the viscosities of the n-alkanes are well represented by the equation log etad log AT BT-T sub o, where d is the density and A, B and T sub o are smooth functions of chain length. The effect of increasing static pressure is to increase A and T sub o, while B is only slightly affected. A diagrammatic method for evaluating steric effects in polymer chains was developed. Some excluded volume effects in rings and short chains of the -CX2- type are elucidated in this way. An empirical approach to estimation of flex energy and hence T sub o is suggested. A statistical-mechanical theory of the glass transition was developed, based on the concept that the observable communal entropy is time dependent. The activation free energy, enthalpy and entropy at the glass temperature were evaluated for several polymers. Intermolecular interactions in liquid alkanes were studied, and an additive property Q BpV0.7240 was found, where Bp is the Antoine vapor pressure constant, and V the molar volume. Q is dependent on the number of C atoms, the number of side branches, and the number of pairs of vicinal branches.
- Polymer Chemistry