A multicomponent insight into the interactions leading to wood pitch deposition

Research has been undertaken to gain a better understanding of the chemical interactions between the components of the wood extractives that cause pitch deposition. The interactions between the main components of the wood extractives, resin acids, fatty acids and triglycerides, have been studied using deposition experiments and computer molecular modelling. The interaction of just two components interacting with each other, either fatty or resin acids with triglycerides, showed that the difference in chemical structure and properties influenced the interaction and also the deposition. This difference in the formation of the hydrogen bond and also the stability, or strength, of the hydrogen bond appears to explain the differences in deposition of fatty acid/resin acid, resin acid/triglyceride and fatty acid/triglyceride mixtures. The deposition results of the three component studies indicate that pitch is related to the solubility of the components as well as hydrogen bond interactions. The stabilisation energies of the resultant complexes are consistent with the proposition that solubility is also influencing the amount of pitch deposited in a three-component system.