The Structure of Some Phenol-Formaldehyde Condensates for Wood Adhesives

Abstract

Abstract The probable minimum-energy structures of three dimeric, three tri-meric, and two hexameric phenol-formaldehyde (PF) condensates were determined by using a simplified model where the total energy was calculated as the sum of the van der Waals, hydrogen bonding, torsional, and electrostatic energies. The minimum-energy conformation was defined as that with internal angles of rotation that correspond to the overall minimum in the total energy. Representations of the structures of these PF condensates in the minimum-energy conformations were obtained. The results obtained indicated that the van der Waals energy, and in some cases the hydrogen bonding energy, make the most important contributions to the total energy. The phenol-formaldehyde dimers and trimers are predicted by this model to have nonplanar structures, and the longer phenol-formaldehyde condensates, such as the hexamers, probably exist in helical conformations.