CHAIN-CONFIGURATIONAL PROPERTIES OF NOVOLAC PHENOL-FORMALDEHYDE RESINS

In the reported theoretical study, 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 plus or minus 80 degree , with the g** plus or minus g** plus or minus stages on the average being 155 cal/mole below the g** plus or minus g** plus or minus 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.