Holz Roh Werkst (2004) 62:378–385 DOI 10.1007/s00107-004-0500-3 ORIGINALARBEITEN · ORIGINALS S. Nami Kartal · Yuji Imamura Effects of N 0 -N-(1, 8-Naphthalyl) hydroxylamine (NHA-Na) and hydroxynaphthalimide (NHA-H) on boron leachability and biological degradation of wood Published online: 7 July 2004  Springer-Verlag 2004 Abstract Although boron wood preservatives have many advantages, boron itself does not adequately protect wood in ground contact and exterior applications because its susceptibility to leaching. As a result of previous studies to limit or decrease boron leaching, several fixation sys- tems have been developed. In this study, we evaluated the effects of N 0 -N-(1, 8-Naphthalyl) hydroxylamine (NHA- Na) and hydroxynaphthalimide (NHA-H) on boron leach- ing and decay and termite resistance via possible bo- ron precipitation in wood after NHA treatments at varying concentrations. Results showed that treatment of wood blocks with disodium octaborate tetrahydrate (DOT), bo- ric acid (BA), or calcium tetraborate (CaB) incorpora- tion with 1.0% NHA-Na solutions in sequential processes appears to somewhat reduce the susceptibility of boron to leaching. Blocks treated sequentially with boron com- pounds and then 1.0% NHA-Na solutions showed about 30% less boron leaching compared to boron only treat- ed blocks. In addition, the existence of boron and NHA- Na in wood together showed a synergistic effect against brown-rot fungus, Fomitopsis palustris. We conclude that the relationship between boron and NHA-Na concentra- tion in wood as regards precipitation possibilities appears to be predictive for reducing boron leachability. Einfluss von N 0 -N-(1, 8-Naphthalyl)-Hydroxylamin (NHA-Na) und Hydroxynaphthalimid (NHA-H) auf die Auslaugbarkeit von Bor und auf den biologischen Abbau von Holz Zusammenfassung Obwohl Schutzmittel auf Borbasis einige Vorteile aufweisen, schützt Bor das Holz nicht ausreichend bei Bodenkontakt und Außenverwendung, weil es leicht ausgewaschen wird. Aufgrund früherer Ergebnisse zum Begrenzen der Auslaugbarkeit von Bor wurden mehrere Fixiersysteme entwickelt. In dieser Ar- beit wird der Einfluss von von N 0 -N-(1, 8-Naphthalyl)- Hydroxylamin (NHA-Na) und Hydroxynaphthalimid (NHA-H) auf die Auslaugbarkeit und die Termitenresis- tenz bewertet. Die Fixierung beruht auf den möglichen Ausfällen von Bor im Holz nach der NHA-Behandlung mit verschiedenen Konzentrationen. Die Ergebnisse zei- gen, dass die Auslaugbarkeit von Bor reduziert werden kann durch aufeinanderfolgendes Behandeln der Holz- klötzchen mit Zusatz von Dinatrium-Octaborat-Tetrahy- drat (DOT), Borsäure (BA) oder Calciumtetraborat (CaB) in 1,0% NHA-Na-Lösung. Klötzchen, die zunächst mit Bor-Komponenten und danach mit 1,0% NHA-Na behan- delt wurden, zeigten eine 30% geringere Auslaugbarkeit im Vergleich zu nur mit Bor behandelten Proben. Zu- sätzlich zeigte die gleichzeitige Anwesenheit von Bor und NHA-Na einen synergistischen Effekt gegen Braunfäule (Fomitopsis palustris). 1 Introduction Considerable attention has been focused on chemical fixation of boron to enable combination of the diffusibility and environmental benefits of boron with the benefits of a fixed preservative for a long time. Boron compounds are considered to be only wood preservatives capable of act- ing as both insecticides and fungicides which are widely recognized and accepted to be effective and of low tox- icity (Thevenon et al. 1997). Boron wood preservatives are also relatively cost-effective chemicals. Despite many advantages of boron wood preservatives, boron itself does not adequately protect wood in ground contact and exte- rior applications because its natural diffusibility and sus- ceptibility to leaching (Kartal and Green 2002). To en- hance the use of boron compounds as environmentally benign wood preservatives, previous researchers have de- vised several fixation systems to limit or decrease boron leaching. As a result, several fixation systems to limit or decrease boron leachability from treated wood have been developed. Some attempts have relied on limiting of water S. N. Kartal ( ) ) · Y. Imamura Research Institute for Sustainable Humanosphere, Kyoto University, Uji, 611-0011 Kyoto, Japan e-mail: nami@rish.kyoto-u.ac.jp Tel.: +81-774-383663 Fax: +81-774-383664