Colloidal silver as innovative multifunctional pigment: The effect of Ag concentration on the durability and biocidal activity of wood paints

This study aims to assess the effect of two different colloidal silver amount on the durability and biocidal activity of a water-borne wood paint. The influence of this multifunctional pigment on the aesthetical features of the coatings was evaluated by colorimetric measurements and optical microscopy observations. The durability of the samples was investigated by means of different accelerated degradation tests, such as the exposure in a climatic chamber and to UV-B radiations. Scanning electron microscope observations, infrared spectroscopy analysis and colorimetric inspections were carried out to highlight the residual influence of silver in altering the protective behavior of the paint. Moreover, the Ag-containing samples exhibited excellent antibacterial activity against Staphylococcus aureus and Escherichia coli, while colloidal silver did not introduce effective fungicidal performances against Coniophora puteana and Trametes versicolor fungi. Ultimately, this work demonstrates how colloidal silver can be used as a functional pigment in wood paint, capable of modifying the appearance of the coating, improving its antibacterial performance, without negatively affecting its protective performance

Tannin- caprolactam and Tannin- PEG formulations as outdoor wood preservatives: Biological Properties

Key Message: This article presents the enhancement in boron fixation as well as the improved biological resistance against fungi and termites for wood samples treated with tannin-caprolactam and tannin-PEG formulations. Context: Although the recently developed tannin-boron wood preservatives have shown high biological protection, they presented also average resistance against weathering. The tannin-caprolactam formulations have shown improved weathering resistances and dimensional stability. Aims: For this reason, more detailed biological tests were performed to evaluate the influence of the caprolactam and PEG on the biological resistance. Methods: In this paper, the boron leaching of the tannin-caprolactam and tannin-PEG impregnated Scots pine specimens was observed and the biocidal effect against fungi (Antrodia spp. and Coniophora puteana) and insects (Reticulitermes flavipes and Hylotrupes bajulus) were determined according to the guidelines of EN 113, EN 117, and EN 47. Results: The advanced formulations containing PEG have shown interesting resistance against fungal decay, but very low penetration and weak resistance against larvae while the tannin-caprolactam preservatives have shown overall improved biological performances and higher boron fixations. Conclusion: The biocidal activity of the caprolactam-added formulations was overall enhanced and therefore these formulations are confirmed to be an interesting alternative for the wood preservation in outdoor environment. (Résumé d'auteur

Copper anchored to amino-group functionalized silica gel as wood preservative against brown-rot decay

The aim of this research was to realize new potential wood preservatives against fungal decay, with low environmental impact and well fixed into the wood.Pinus sylvestris L. wood samples were impregnated by silica xerogels functionalized with amino groups able to link copper through coordinative interactions. In this study tetraethoxysilane (TEOS) and 3-aminopropyltriethoxysilane (APTES), in different ratios, and linked with copper or not, were utilized to impregnate wood samples, in order to evaluate the factors responsible for the efficacy against the brown rot Coniophora puteana. The fixation to the wood was evaluated through the leaching procedure (EN 84) and the variation on the effectiveness against this fungus.The sol-gel processes TEOS/APTES, ratio 1:1, with or without copper, leached or not leached, showed a good effectiveness against fungus C. puteana

Tannin- caprolactam and Tannin- PEG formulations as outdoor wood preservatives: Weathering properties

International audienceAbstractKey messageThis article presents the leaching, fire and weathering resistance improvements of samples treated with tannin-based wood preservatives added of caprolactam. PEG-added formulations show limited applicability. The FT-IR and13C-NMR analyses of the caprolactam-added formulations show some evidences of copolymerization.ContextTannin-boron wood preservatives are known for their high resistance against leaching, biological attacks, fire as well as for the good mechanical properties that they impart to wood. These properties promoted these formulations for being a candidate for the protection of green buildings. However, the low elasticity of these polymers and their dark colour implied limited weathering resistances.AimsThe aim of the study is to find suitable additives for tannin-based formulations to overcome their limited weathering resistances, without compromising the other properties.MethodsTreatment, leaching and fire tests, dimensional stability as well as artificial and natural weathering of the timber treated with caprolactam-added and PEG-added formulations were performed. FT-IR and 13C-NMR of the formulations were presented.ResultsThe presence of caprolactam improved the properties of the formulation with particularly significant results in terms of resistance against leaching and dimensional stability. These enhancements were imparted also to the weathering resistance of the tannin-caprolactam formulations. Indeed, the colour changes during the artificial and natural exposures were stable for longer periods. FT-IR and 13C-NMR investigations of the advanced formulations were led, and covalent copolymerization of the caprolactam with the tannin-hexamine polymer was observed.ConclusionThe tannin formulations with caprolactam improved the durability of the wood specimens, while the PEG-tannin presented strong application drawbacks

Copper complexes grafted to functionalized silica gel as wood preservatives against fungal decay: mini-blocks and standard test

Previous preliminary studies showed good efficacy of treatments based on a mixture of siloxane materials, functionalized with amino groups and coupled with copper, against the brown rot fungus Coniophora puteana (Palanti et al. 2011). In the present work, a one-step impregnation was performed on two sets of samples differing in size, in order to verify and compare the homogeneity of treatments. Leaching and resistance against brown rot and white rot fungi were also tested according to European standards EN 84 and EN 113, respectively. Furthermore, an accelerated test of efficacy against fungal decay was also used for determining the treatment efficacy. The obtained results made it possible to validate the findings of the preliminary study concerning resistance of the treated wood against C. puteana, while extending them to the white rot fungus Trametes versicolor. In contrast, no protection was conferred by the treatment against the copper-tolerant fungus Poria placenta

COPPER ANCHORED TO AMINO-GROUP FUNCTIONALIZED SILICA GEL AS WOOD PRESERVATIVE AGAINST BROWN-ROT DECAY

The aim of this research was to realize new potential wood preservatives against fungal decay, with low environmental impact and well fixed into the wood. Pinus sylvestris L. wood samples were impregnated by silica xerogels functionalized with amino groups able to link copper through coordinative interactions. In this study tetraethoxysilane (TEOS) and 3-aminopropyltriethoxysilane (APTES), in different ratios, and linked with copper or not, were utilized to impregnate wood samples, in order to evaluate the factors responsible for the efficacy against the brown rot Coniophora puteana. The fixation to the wood was evaluated through the leaching procedure (EN 84) and the variation on the effectiveness against this fungus. The sol-gel processes TEOS/APTES, ratio 1:1, with or without copper, leached or not leached, showed a good effectiveness against fungus C. puteana

Cooper anchored to amino-group functionalized silica gel as wood preservative against brown-rot decay

The aim of this research was to realize new potential wood preservatives against fungaldecay, with low environmental impact and well fixed into the wood.Pinus sylvestris L. wood samples were impregnated by silica xerogels functionalized withamino groups able to link copper through coordinative interactions. In this study tetraethoxysilane(TEOS) and 3-aminopropyltriethoxysilane (APTES), in different ratios, and linked with copper ornot, were utilized to impregnate wood samples, in order to evaluate the factors responsible for theefficacy against the brown rot Coniophora puteana. The fixation to the wood was evaluated throughthe leaching procedure (EN 84) and the variation on the effectiveness against this fungus.The sol-gel processes TEOS/APTES, ratio 1:1, with or without copper, leached or notleached, showed a good effectiveness against fungus C. puteana