The overall aim of this project was to develop the concept of using new vegetable oil based treatments on exterior wood to improve the outdoor durability. The drying mechanisms of the unsaturated fatty acids with wood model system in the real time were monitored by using RT-IR. This method together with solid-NMR is enormously powerful spectroscopy techniques to determine the physical and chemical properties of fatty acids-wood during the oxidation process over time. In the first part of this study the focus was in a molecular level on oxidation of methyl linoleate mixed with lignin model compounds. The effect of lignin structures on unsaturation fatty acids oxidation was determined with 1 wt% lignin model compounds by using RT-IR. The wood model compounds minimize the complexity of all elements that exist normally in the natural wood. In general phenolic lignin or conjugated lignin structures were observed to inhibit the oil oxidation (drying) process. The oil oxidation interaction mechanisms were also evaluated by using methyl linoleate, methyl oleate and Linola® on solid wood. This study indicated that the oxidation pattern of fatty acids behaved differently on wood surface. The results from these studies clearly show that an improved performance of vegetable oil treatments on wood can be obtained by an appropriate choice of oil structure. The general conclusion is that a high enough reactivity to obtain an immobilized oil layer is needed but that a too reactive oil system will reduce the long term durability.
Keywords: Methyl linoleate, fatty acids auto-oxidation, lignin, RT-IR, solid NMR
Authors
Salehi A.
Wallenberg Wood Science Centre (WWSC), Department of Fiber and Polymer Technology, School of Chemical Science and Engineering. KTH, Royal Institute of Technology Stockholm, Sweden
Trey S.M.
Henriksson G.
Pagès G.
Salehi A.M.
Dvinskikh S.V.
Furó I.
Johansson M.
Login to download the PDF