1. Vpliv kondicioniranja na vezavo baker-etanolaminskih zaščitnih sredstev
- Author
-
Žlahtič, Mojca and Humar, Miha
- Subjects
zaščita ,vezava ,leaching ,fixation ,les ,preservation ,copper-ethanolamine preservatives ,izpiranje ,udc:630*841 ,baker-etanolaminski pripravki ,wood - Abstract
Les na prostem je izpostavljen različnim dejavnikom razgradnje, ki so v naravi dobrodošli, v gospodarske namene pa navadno nezaželeni. Baker-etanolaminski pripravki so trenutno najpomembnejša skupina zaščitnih sredstev za zaščito lesa v III. in IV. razredu izpostavitve. Ti pripravki se praviloma dobro vežejo v les, v posameznih primerih pa je opaziti poslabšano vezavo. Le-to pripisujemo neustreznemu kondicioniranju impregniranega lesa. Smrekove vzorce dimenzij (1,5 x 2,5 x 5,0) cm3 (SIST EN 113, 2006) smo impregnirali s komercialnim pripravkom Silvanolinom, 2 različnih koncentracij: 0,25 % Cu in 0,125 % Cu. Preizkušance smo impregnirali v vakuumsko-tlačni komori Kambič. Po končani impregnaciji smo iz dobljenih podatkov izračunali mokri navzem z gravimetrižno metodo in vzorce izpostavili različnim režimom sušenja. Za vsak režim (10 režimov) smo uporabili po 6 vzorcev. Po končanem kondicioniranju je sledilo izpiranje, ki je potekalo v skladu z modificirano standardno laboratorijsko metodo SIST ENV 1250-2. Delež izpranih učinkovin je bil določen po 1. dnevu in po koncu izpiranja iz izpirkov, ki smo jih shranjevali v ta namen. Izpirke smo analizirali z rentgensko flourescenčno spektroskopijo (XRF, Oxford intruments) in atomsko absorpcijsko spektroskopijo (AAS VARIAN SPECTRA AA DUO FS240). Ugotovili smo, da povišana temperatura in visoka relativna vlažnost med kondicioniranjem negativno vplivata na vezavo baker-etanolaminskih pripravkov. V kolikor želimo zagotoviti ustrezno vezavo omenjenih zaščitnih sredstev v les, je najbolje, da jih po končani impregnaciji izpostavimo zmernemu sušenju na prostem, pri čemer ne smemo izpostavljati zaščitenega lesa previsokim temperaturam in spreminjajočim se vremenskim pogojem. Wood in outdoor applications is susceptible to decay and degradation caused by various factors, and although this process might be important in carbon cycle, it is much less desirable phenomenon when wood is used in commercial applications. Copper-ethanolamine based wood preservatives are currently the most important group of preservatives for protection of wood in use classes III and IV. Fixation of these wood preservatives is generally good, although in some cases a decreased fixation can be noticeable. The main reason for this occurrence is presumably unsuitable conditioning of impregnated wood. In the research, spruce wood specimens with dimensions (1.5 x 2.5 x 5.0) cm3 (EN 113, 2006) were impregnated with the Silvanolin commercial solution of 2 different concentrations (0.25 % Cu and 0.125 % Cu). Impregnation of the specimens was performed in a vacuum-pressure chamber, and afterwards retention was determined gravimetrically. After the impregnation, the specimens were exposed to 10 different drying procedures. For each drying procedure 6 specimens were used. Afterwards, the specimens were leached according to the modified standard method ENV 1250-2. After the first and the last day of leaching, the amount of ingredients in leachates was analyzed withX-ray fluorescence spectroscopy (XRF, Oxford instruments) and atomic absorption spectroscopy (AAS VARIAN SPECTRA AA DUO FS240). The results showed that increased temperatures and high relative humidity during conditioning negatively influenced the fixation of copper-ethanolamine preservatives. In order to provide a proper fixation of afore mentioned preservatives in wood, it is suggested to expose them to moderate drying in the open air after impregnation, whereby the preserved wood should not be exposed to too high temperatures and oscillating weather conditions.
- Published
- 2014