Configurational statistics of polylactone chains

✍ Scribed by S. Brückner; V. Crescenzi; L. Zotteri

• Publisher: Elsevier Science
• Year: 1971
• Tongue: English
• Weight: 589 KB
• Volume: 7
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(71)90040-1

✦ Synopsis

The unperturbed dimensions of poly-~-caprolactone (P~L), poly-t-propiolaetone (PilL) and polypivalolactone (PPL) have been evaluated theoretically. We find that the values of the characteristic ratio, C®, are 6" 66 (P~L), 3" 98 (P3L) and 8" 10 (PPL).

The calculations are based, as usual, on the isomeric rotational state model. Statistical weights are assigned to allowed rotational states around the different bonds along polylactone chains on the basis of indications derived from conformational van der Waals energy maps and by analogy with the cases of other similar chains studied by other authors. Dipolar interactions were not explicitly taken into account. Theoretical evaluations of the mean square dipole moments of P~L, PilL and PPL chains axe also made.

Correlation of theory and experiment must await more detailed investigations, as experimental data are limited to the PEL case for which there is apparently a disagreement between our C® value and that extrapolated from intrinsic viscosity data (in good solvents).

Theoretical C® values, however, depend critically on the choice of the values of one or two staffstical weights: theory is thus flexible enough to lead to ready agreement with information from future and reliable experimental data.