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  Drafz, M.H.H.; Franz, A.; Namyslo, J.C.; Kaufmann, D.E.: Chemistry and Spectroscopy of Renewable Materials, Part 1: Imaging the Penetration Depth of Covalent Wood Modification. ACS Sustainable Chemistry & Engineering 3 (2015), p. 566-568

10.1021/sc5008048

Abstract:
The covalent modification of pine sapwood by benzotriazolyl activated benzoic acids offers broad access to new, durable functional materials. The penetration depth of these substituted benzoic acids remained unknown so far. Two independent proofs were received for the first time by parallel 3D-μCT imaging and attenuated total reflection infrared spectroscopy studies on approximately 10 × 10 × 10 mm wood cubes esterified with activated p-bromobenzoic acid. It proved feasible to penetrate pine sapwood anisotropically as deep as 4.5 (with the grain) to 0.75 mm (across the grain), depending on the orientation of the fibers. The results prove the usability of the applied modification procedure.