Chemical improvement of surfaces. Part 3: Covalent modification of Scots pine sapwood with substituted benzoates providing resistance to Aureobasidium pullulans staining fungi

Abstract

Abstract The development of appropriate chemical precursors that can covalently functionalize natural wood aims at efficient restriction of deterioration. Biological staining experiments were performed with veneer pieces made of sapwood of Scots pine (Pinus sylvestris L.) that had previously been chemically modified with substituted benzoates. Based on the recently published protocol on esterification of wood by means of 1H-benzotriazole activation, the quantity of covalently bonded organomaterials (QCOs), a recently defined advantageous value considering the individual molecular weight of the functionalizing organochemical groups, was obtained in the range of 0.9–1.5 mmol g-1. The modified wood was analyzed by attenuated total reflection IR spectroscopy. Modification with three electronically different benzoates clearly reduced the colonization of the specimen’s surfaces by the blue stain fungus Aureobasidium pullulans but did not fully prevent it. The degree of colonization appeared to decrease with increasing QCO values of the modification agents but apparently did not strongly depend on the additional functionality of the benzoate.