Ss. Choi, Structural characteristics of phenol formaldehyde novolak resin depending on polycondensation type using molecular simulation, POLYM ADV T, 12(10), 2001, pp. 567-573
Phenol formaldehyde novolak resins have various structures depending on the
polycondensation types. Their structures were characterized using molecula
r mechanics and molecular dynamics. Dimer, tetramer, hexamer, octamer, and
decamer of the resins with the ortho-ortho, ortho-para, and para-para seque
nces were calculated. The ortho-ortho resins have the structural characteri
stics of intramolecular hydrogen bonds between hydroxyl groups of the adjac
ent phenolic units. For the ortho-para and para-para resins, the intramolec
ular hydrogen bonds are formed mainly between hydroxyl groups of the backbo
ne phenolic units. The para-para resins also have intramolecular hydrogen b
onds between hydroxyl groups of the branched phenolic units. A factor deter
mining the structural characteristics of the resins was found to be the geo
metry of the basic unit (dimer). The order of the end-to-end distances betw
een hydrogen atoms on the para-position of the basic units of the resins is
ortho-ortho resin < ortho-para resin < para-para resin. The calculational
results were found to be consistent with the gel permeation chromatography
(GPC) analysis. Copyright (C) 2001 John Wiley & Sons, Ltd.