The Influence of Stereoregularity on the Glass Transition Temperatures of Vinyl PolymersMacromolecules (1968)
Correlation of available data for glass transition temperatures of mono- and disubstituted vinyl polymers, (CH,CXY)n, leads to the conclusion that steric configuration affects T, only when X >6- Y and neither X or Y is hydrogen. Conversely, T, is independent of configuration when hydrogen is one of the substituents. A basis for this observation can be developed in terms of the Gibbs-DiMarzio theory if it is postulated that (a) the effect of configuration in disubstituted polymers is intramolecular and is brought about by changes in the flex energy of the isomers, and (b) changes in Tg due to side-chain modification are strictly intermolecular. Using the Simha-Boyer constant of 0.113 for the product T,Lla (where Ila is the difference in the volume expansion coefficient above and below T,), the unoccupied volumes at T. and the flex energy differences for the syndiotactic and isotactic poly(methyl methacrylates) were calculated. The above postulates imply that the configurationinduced difference in T, in the poly(alkyl methacrylates) should be constant. This appears to be approximately true, but cannot be properly verified as yet because the completely syndiotactic polymers have not been prepared.
- Glass Transition Temperature,
- Vinyl Polymers
Citation InformationWilliam MacKnight. "The Influence of Stereoregularity on the Glass Transition Temperatures of Vinyl Polymers" Macromolecules Vol. 1 (1968) p. 537 - 540
Available at: http://works.bepress.com/william_macknight/14/