Furfurylation is one of the wood modification techniques via catalytic polymerization of the monomeric furfuryl alcohol (FA) in the impregnated cell wall. Little is known about the topochemistry of this process. Brown rot degradation begins with lignin modification and therefore, the reactions between FA and lignin was one focus of this research. Furfurylated radiata pine (Pinus radiata) with three different weight percent gains (WPGs of 57%, 60% and 70%) after FA uptake was observed by cellular ultraviolet microspectrophotometry (UMSP) to analyze chemical alterations of the individual cell wall layers. Moreover, light microscopy (LM) and scanning electron microscopy (SEM) analyses were performed. The ultraviolet (UV) absorbance of the modified samples increased significantly compared to the untreated controls, indicating a strong polymerization of the aromatic compounds. Highest UV absorbances were found in areas with the highest lignin concentration. The UMSP images of individual cell wall layers support the hypothesis concerning condensation reactions between lignin and FA.

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Today there is an increasing demand for wood protection systems which are based on low environmental impact technologies. The aim of this study was to improve a method for investigating furfurylated Pinus radiata, both in terms of the furfuryl alcohol polymerisation process in the wood cell wall and the detection of initial signs of brown rot degradation. It is an established theory today that brown rot degradation starts with lignin modification in the outermost part of the secondary cell wall and the combined middle lamella. We adapted a method (cellular UV microspectrophotometry, UMSP) which enables direct imaging of the lignin distribution and modification within individual cell wall layers. Furfurylated P. radiata, incubated with Postia placenta, were scanned with monochromatic UV-light at 280 nm. The results showed that USMP is a promising method to study furfurylated wood and early fungal degradation damages in the cell wall of furfurylated wood.