Performance of wood treated with iron ions and biocides against wood decay fungi and water

Zaradi ekološkega vidika in poznavanja pravilne rabe lesa njegova uporaba vedno bolj narašča. Številnim uporabnikom je všečen neobdelan naravno posivel videz lesa. Ker so procesi fotodegradacije različni glede na zaščito, način vgradnje, mesta vgradnje, orientacije strani neba itd., smo razvili pripravek, ki odstrani oz. zelo zmanjša te vplive in poenoti videz lesa na vseh mestih in načinih vgradnje. Osnovna raztopina je bila sestavljena iz demineralizirane vode in železovega(II) sulfata (FeSO4). V različnih kombinacijah in koncentracijah smo dodajali borovo kislino (Ba) ter kvartarne amonijeve spojine (QUAT), ki se uporabljata za biocidno zaščito. Pripravke smo testirali na lesu macesna (Larix decidua Mill.) in smreke (Picea abies Karst.). Macesen smo uporabili le pri zunanji izpostavitvi. Vzorce smo pred testiranjem za deset minut potopili v različne kombinacije raztopin. Polovico smo jih nato izpostavili delovanju sevanja UV. Naredili smo test odpornosti proti glivam razkrojevalkam. Pri netretiranih vzorcih smo izmerili povprečno izgubo mase 17,16 %. Najboljšo zaščito lesa smo dosegli s pripravkom 5 % FeSO4 + 0,2 % Ba + 0,2 % QUAT. Prav tako se je ta pripravek najboljše obnesel pri kratkotrajnem in dolgotrajnem potapljanju ter pri izpostavitvi 100 % zračni vlažnosti. Povprečna vsebnost železa po obdelavi, izmerjena na XRF, je znašala približno 990 ppm in se je po prvem tednu skoraj prepolovila. Končna vsebnost po 9 mesecih je bila nekje 80 ppm. Železov sulfat reagira z lesom in v nekaj dneh vzorci pridobijo sivo patino podobno kot pri naravnemu staranju. Obdelani vzorci so po enem tednu že temnejši, kot neobdelani po 9 mesecih.The use of wood is increasing for both ecological reasons and because of greater knowledge of its proper use. The untreated naturally grayed appearance of the wood is interesting. Since the aging processes are different depending on the method of protection, method of installation, the place of installation, the orientation of the sides, etc., we have developed a preparation that removes or greatly reduces those effects and unifies the appearance of wood in all places and methods of installation. The basic solution was composed of demineralized water and iron (II) sulfate (FeSO4). Boric acid (Ba) and quaternary ammonium compounds (QUAT), which are used for biocidal protection, were added in various combinations and concentrations. The preparations were tested on larch (Larix decidua Mill.) and spruce (Picea abies Karst.) wood. We used larch wood only for external exposure. Then we immersed the samples in various combinations of solutions for ten minutes before testing. Half of them were than exposed to UV. We also did a test of resistance to decaying fungi. We measured an average weight loss of 17.16 % in untreated samples. The best wood protection was achieved with 5 % FeSO4 + 0.2 % Ba + 0.2 % QUAT. In addition, this preparation performed its best in short-term immersion, long-term immersion and exposure at 100 % humidity. The average iron content was about 990 ppm after treatment and measured on XRF, and it almost halved after the first week. After 9 months the final content was somewhere around 80 ppm. Iron sulfate reacts with wood, and in a few days the samples gain a gray patina similar to natural aging. After one week, treated samples are already darker than untreated samples after 9 months