| Abstract: | Rotational isomeric-state chain-configurational calculations have been applied to the novolac phenol–formaldehyde structure. Steric interference allows the chain to be considered with a twofold potential energy barrier model. Computations that fit the observed dipole-moment data over a range of molecular weights indicate that the conformational angle is near ±80°, with the g±g= states on the average being 155 cal/mole below the g±g± states. The limiting dipole-moment ratio is computed to be 1.47, compared to the experimental value of 1.48. A negative temperature coefficient agrees in sign with the experimental value, and the characteristic ratio of the end-to-end molecular dimensions is calculated to be 3.27, as compared to the experimental value of 4.76. |
