Effects of polyvinyl alcohol on leachability and efficacy of boron wood preservatives against fungal decay and termite attack

Abstract

In this study, the use of polyvinyl alcohol (PVA) as boron fixative agent was investigated. Two levels of PVA (2.5 and 4%) were evaluated with disodium octaborate tetrahydrate (DOT) at three concentrations (1, 2 and 4% boric acid equivalent (BAE)) using a double vacuum impregnation process on Scots pine sapwood specimens. Leaching was performed according to a laboratory leaching procedure. Boron analysis using atomic absorption spectrometer showed a significant reduction in boron leachability for the samples treated with both concentrations of PVA when compared to the stand-alone boron treatment leading to boron retentions capable of preventing wood biological degradations. Decay resistance of the leached specimens was evaluated using the brown rot fungus Poria placenta. Even if complete protection was not fully achieved, an improvement in decay resistance was observed for the samples treated with DOT in presence of PVA. This leak of efficacy was attributed to a decrease in the biological activity of the complexed boron against fungi. Durability of treated wood against termite attack, evaluated using Reticulitermes santonensis, indicated a significant enhancement for the samples treated in presence of the fixative agent compared to the pure boron treatment (Résumé d'auteur)

Thermal degradation of oriental beech wood impregnated with different inorganic salts

“…APP and boron compounds retard flame by producing carbona-ceous foam which protects the material from temperature rise (Kurt and Mengeloglu 2011). Boron compounds, such as disodium octaborate tetrahydrate (DOT), boric acid and borax are odourless, colourless, non-corrosive, cheap and non-toxic chemicals (Mohareb et al 2011). However, the leaching of boron compounds from wood has been one of the significant problems for over years.…”

Fungicides for Wood Protection - World Viewpoint and Evaluation/Testing in Slovakia

“…Inorganic boron compounds used in outdoor exposures have to be modified with fixatives or with water repellents, polymerizable monomers or other protective additives to reduce their leachability (Babuder et al 2004, Lloyd et al 2001. Polyvinyl alcohols belong to the most known fixatives which form stable complex with the borate ions (Mohareb et al 2010a). Complexes with boron create also tannins (Pizzi & Baecker 1996).…”

Water Transport Mechanisms of Poly(acrylic acid), Poly(vinyl alcohol), and Poly(ethylene glycol) in C–S–H Nanochannels: A Molecular Dynamics Study

“…PVA has a broad range of applications in the medical, 9 agricultural, 10,11 industrial, 12 and manufacturing industries. In addition, PVA is also used in the construction industry as a building binder, a cement-based composite material modifier, a fiber reinforcement, and so on.…”

“…PVA has a broad range of applications in the medical, agricultural, , industrial, and manufacturing industries. In addition, PVA is also used in the construction industry as a building binder, a cement-based composite material modifier, a fiber reinforcement, and so on. − It can significantly increase the fracture energy and improve the cracking problems of cement-based materials. ,− Kou evaluated the effect of PVA on the durability of recycled aggregate concrete and found that the introduction of PVA can reduce the water absorption of the matrix, thereby enhancing the resistance to chloride ion penetration.…”