Utjecaj količine otapala u utekućenom drvu i dodatka kondenziranog tanina na kvalitetu vezanja

Liquefied wood (LW) is a promising natural material that can be used as a part of the adhesive formulation. However, adhesive bonds made of LW only, have low durability. The aim of this study was, therefore, to increase the durability of adhesive bonds containing LW. LW was obtained with liquefaction of black poplar wood in ethylene glycol (EG) as the solvent and sulphuric acid (SA) as the catalyst. An optimal time of 120 minutes and a wood/EG mass ratio of 1:3 was defi ned for liquefaction at 180 °C. After liquefaction, the EG was evaporated in order to achieve a low solvent content LW with a fi nal mass ratio of 1:1. A hydroxyl number for 1:3 and 1:1 LW was determined in order to examine the reduction of hydroxyl groups. Four different adhesive mixtures were prepared: LW with a mass ratio of 1:1 (LW1:1 ), LW with a mass ratio of 1:3 (LW1:3 ), LW with a mass ratio of 1:1 and added condensed tannin (CT) (LW1:1 /CT), and LW with a mass ratio of 1:3 and added CT (LW1:3 /CT). The solid beech wood lamellas, which were bonded with these adhesive mixtures, were tested directly after bonding, and later on, after 7, 30 and 50 days. The test results indicated greater bonding shear strength in the case of LW1:1 compared to LW1:3. The addition of CT did not contribute to essentially higher shear strength values. The adhesive mixtures LW1:1 and LW1:1 /CT (uncured and cured) were analyzed using FT-IR spectroscopy. No significant differences were observed between the cured LW1:1 and the LW1:1 /CT samples.Utekućeno drvo (LW) perspektivan je prirodni materijal koji može biti upotrijebljen kao tvar za izradu ljepila. Međutim, vezivna ljepila napravljena samo od utekućenog drva imaju malu trajnost. Stoga je cilj provedenih istraživanja bio povećati trajnost vezivnih ljepila koja sadržavaju LW. U provedenim je istraživanjima LW dobiven utekućenjem drva topole u etilen glikolu (EG) kao otapalu i sumpornoj kiselini (SA) kao katalizatoru. Definirano je optimalno vrijeme utekućenja od 120 minuta i maseni omjer drvo:EG u iznosu 1:3 za utekućenje pri temperaturi 180 °C. Nakon utekućenja EG je ishlapljen da bi se postigao nizak sadržaj otapala u LW-u s konačnim masenim omjerom 1:1. Utvrđen je hidroksilni broj za LW s omjerom 1:3 i LW s omjerom 1:1 da bi se ispitalo smanjenje broja hidroksilnih skupina. Pripremljene su četiri različite mješavine ljepila: LW s masenim omjerom 1:1 (LW1:1 ), LW s masenim omjerom 1:3 (LW1:3 ), LW s masenim omjerom 1:1 te dodanim kondenziranim taninom (CT) (LW1:1 /CT), i LW s masenim omjerom 1:3 i dodanim CT-om (LW1:3 /CT). Lamele od bukovine lijepljene su navedenim mješavinama ljepila i ispitane odmah nakon lijepljenja, zatim nakon 7, 30 i 50 dana. Rezultati testa pokazali su veću smicajnu čvrstoću vezanja u slučaju LW1:1 u odnosu prema LW1:3 . Dodavanje CT-a nije znatno pridonijelo većoj smicajnoj čvrstoći. Mješavine ljepila LW1:1 i LW1:1 /CT (nesušene i osušene) analizirane su FT-IR spektroskopijom. Nisu zapažene signifi kantne razlike između osušenih uzoraka LW1:1 i LW1:1 /CT

Mogućnosti uporabe utekućenoga otpadnog drva obrađenoga krom-bakar-boratom za zaštitu drva

Recovered wood is frequently contaminated with biocides and therefore its use is limited. Even more, wood, impregnated with classical chromated copper arsenate (CCA) preservatives is classified as a hazardous waste, therefore solutions for reuse or recovery of this material are sought. One of the options, discussed in this paper is liquefaction and further applications of liquefied wood containing biocide remainings. In order to elucidate this possibilty, spruce and beech wood was impregnated with liquefi ed CCB treated and untreaded spruce wood of various concentrations and exposed to wood decay fungi according to the EN 113 procedure. In paralel, the leaching experiments (ENV 1250-2) were performed as well. The results do not clearly show that liquefied wood is bio-inactive. In most cases the mass loss by fungal attack is decreased compared to the untreated controls. On the other hand, copper leaching from spruce wood, impregnated with the liquefi ed CCB treated wood was significantly reduced. Thus, there are indications that the liquefied wood could be utilized as a binding agent for inorganic biocides.Prikupljeno uporabljeno drvo često je onečišćeno biocidima te je njegova ponovna uporaba ograničena. Osim toga, drvo impregnirano klasičnim krom-bakar-arsenat (CCA) zaštitnim sredstvima klasificirano je kao opasni otpad te je nužno pronaći rješenje za ponovnu uporabu ili sanaciju tako onečišćenog drva. Jedna od mogućnosti, prezentirana u ovome radu, jest utekućenje drva i daljnja primjena tako utekućenog drva koje sadržava preostale biocide. Radi razjašnjenja te mogućnosti, smrekovo i bukovo drvo impregnirano je utekućenom nezaštićenom smrekovinom i utekućenom smrekovinom zaštićenom krom-bakar-boratom različitih koncentracija. Tako obrađeno drvo izloženo je djelovanju gljiva, sukladno postupku opisanom u normi EN 113. Paralelno je proveden eksperiment ispiranja (ENV 1250-2). Rezultati istraživanja nisu jasno pokazali da utekućeno drvo nije bioaktivno. U većini je slučajeva gubitak mase zbog djelovanja gljiva smanjen u usporedbi s neobrađenim kontrolnim uzorcima. Osim toga, ispiranje bakra iz smrekovine impregnirane utekućenim drvom zaštićenim CCB-om znatno je smanjeno. Prema tomu, postoje znakovi da se utekućeno drvo može upotrijebiti kao vezivno sredstvo za anorganske biocide

The wood of teak (Tectona grandis L.)

Teak (Tectona grandis L.) belongs to most precious and desired wood species. Because of reduced supply of teak wood from natural forests in Southeast Asia,mainly the plantation wood from different tropical regions is available on the market. We present the properties of nature grown teak wood compared tothose of wood from the plantations. Teak wood from natural forests generallycontains a greater portion of coloured heartwood containing hydrophobic caoutchouc and high content of biologically active extractives like lapachol, deoxylapachol, 2 methylanthraquinone (tectoquinone) and 2-hydroxymethylanthraquinone. The heartwood of teak is distinguished by its decorative appearance, high natural durability and dimensional stability. Trees from plantations are usually fast grown, have smaller stems and high proportion of sapwood and juvenile wood. Heartwood-formation can be less intensive which leads to reduced natural durability. The wood from plantations is not necessarily of lower quality, but it is likely more variable than the wood form natural sites

Tung oil

V Tungovo ali kitajsko olje pridobivajo iz semen plodov tungovca, ki raste na kitajskem že stoletja. Olje ima izredno cenjene sušilne, polimerizacijske in odpornostne lastnosti zaradi visoke reaktivnosti sistema konjugiranih vezi a-eleostearinske maščobne kisline. Olje se na tržišču se nahaja v čisti, modificirani in polimerizirani obliki. Nanašanje olje je enostavno, filmi, ki jih tvori pa imajo odlične odpornost proti vlagi, acetonu, etanolu in alkalijam, zato lahko olje uporabljamo v najrazličnejše namene površinske obdelave ter zaščite lesa. Utrjeno olje je nestrupeno ter tako tudi primerno za uporabo na izdelkih, ki so v stiku s živili.Tung oil is obtained from the kernels of the fruit of the tung tree which has been grown in China for centuries. The oil has valuable drying and polymerization properties because of the high content of ?- eleostearic acid. There are three types of tung oil: pure tung oil modified tung oil and polymerized tung oil. Oil is easy to apply and the coating has superior resistances against water, alcohol, acid and weathering. Therefore it has found a lot of applications in wood protection. Dried oil is non toxic and therefore it is very suitable for protection of woody products which are coming in contact with food

The wood of teak (Tectona grandis L.)

Tikovina (Tectona granids L.) spada med najbolj dragocene in zaželene lesne vrste. Ker lesa tika z naravnih rastišč v JV Aziji primanjkuje, se na trgu v glavnem pojavlja les s plantaž z različnih območij tropskega pasu. Podajamo pregled in primerjavo lastnosti lesa iz naravnih sestojev in s plantaž. Tikovino iz naravnih sestojev odlikuje velik delež intenzivno obarvane jedrovine z večjimi količinami ekstraktivnih snovi med katerimi so vodoodbojni kavčuk ter biološko aktivni lapahol, deoksilapahol, 2-metilantrakinon (tektokinon) in 2-hidroksimetilantrakinon. Jedrovino tika odlikuje dekorativnost, visoka naravna trajnost in ugodna dimenzijska stabilnost. Za les s plantaž je značilna hitra rast, manjše dimenzije debel ter velik delež beljave in juvenilnega lesa. Ojedritev je lahko manj intenzivna, kar se odraža predvsem v slabši naravni trajnosti. Lastnosti lesa s plantaž niso obvezno slabše kot lastnosti lesa iz naravnih sestojev, so pa bolj variabilne.Teak (Tectona grandis L.) belongs to most precious and desired wood species. Because of reduced supply of teak wood from natural forests in Southeast Asia,mainly the plantation wood from different tropical regions is available on the market. We present the properties of nature grown teak wood compared tothose of wood from the plantations. Teak wood from natural forests generallycontains a greater portion of coloured heartwood containing hydrophobic caoutchouc and high content of biologically active extractives like lapachol, deoxylapachol, 2 methylanthraquinone (tectoquinone) and 2-hydroxymethylanthraquinone. The heartwood of teak is distinguished by its decorative appearance, high natural durability and dimensional stability. Trees from plantations are usually fast grown, have smaller stems and high proportion of sapwood and juvenile wood. Heartwood-formation can be less intensive which leads to reduced natural durability. The wood from plantations is not necessarily of lower quality, but it is likely more variable than the wood form natural sites

Influence of liquefied and ccb containing liquefied wood on growth of wood decay fungi

There are high amounts of post-consumed protected waste wood removed from service every year. The residual biocides, including copper, chromium and boron from CCB (Cu, Cr, B) in post-consumed wood that was protected with biocides may cause environmental problems during waste management, for example during land filling. Therefore, the aim of this study was to find out if Cu and Cr in the processed waste wood, previously treated with CCB, can be re-used as a wood preservative or in coatings made of liquefied wood. Liquefaction of CCB containing waste wood could be as well the first step in the elimination process of metals. So, the optimal conditions for liquefaction of CCB (Cu, Cr and B) containing black poplar (Populus nigra L.) wood were established and compared with liquefaction of uncontaminated black poplar wood. The reactants for liquefaction of black poplar wood sawdust were ethylene glycol (EG) and sulphuric acid. It was observed that in the last stages of the liquefaction process, the presence of Cu, Cr and B did not have any influence on liquefaction yield (LY), while their influence was observed in first stages of the solvolytic reaction. Investigations of fungicidal properties of uncontaminated and CCB containing liquefied wood showed higher antifungal efficacy of liquefied wood without Cu, Cr and B than of liquefied wood that contained CCB. In the tested concentration range, the presence of Cu even promoted the growth of selected wood decay fungi. One of the reasons for higher toxicity of liquefied black poplar sawdust without Cu, Cr and B, was its very low pH value

Influence of liquefied and ccb containing liquefied wood on growth of wood decay fungi

There are high amounts of post-consumed protected waste wood removed from service every year. The residual biocides, including copper, chromium and boron from CCB (Cu, Cr, B) in post-consumed wood that was protected with biocides may cause environmental problems during waste management, for exampl eduring land filling. Therefore, the aim of this study was to find out if Cu and Cr in the processed waste wood, previously treated with CCB, can be re-used as a wood preservative or in coatings made of liquefied wood. Liquefaction of CCB containing waste wood could be as well the first step in the elimination process of metals. So, the optimal conditions for liquefaction of CCB (Cu, Cr and B) containing black poplar (Populus nigra L.) wood were established and compared with liquefaction of uncontaminated black poplar wood. The reactants for liquefaction of black poplar wood sawdust were ethylene glycol (EG) and sulphuric acid. It was observed that in the last stages of the liquefaction process, the presence of Cu, Cr and B did not have any influence on liquefaction yield (LY), while their influence was observed in first stages of the solvolytic reaction. Investigations of fungicidal properties of uncontaminated and CCB containing liquefied wood showed higher antifungal efficacy of liquefied wood without Cu, Cr and B than of liquefied wood that contained CCB. In the tested concentration range, the presence of Cueven promoted the growth of selected wood decay fungi. One of the reasons for higher toxicity of liquefied black poplar sawdust without Cu, Cr and B, was its very low pH value

Vpliv temperature na stopnjo kanibalizma med ličinkami navadne tenčičarice (Chrysoperla carnea Stephens, Neuroptera, Chrysopidae)

Paper presents a larval cannibalism of green lacewings (Chrysoperla carnea ), which was observed during the laboratory bioassay on non-target effect of entomopathogenic nematodes against green lacewings larvae. The most probable reason for larval cannibalism were undersized Petri dishes in which the bioassay was performed. Due to large number of larvae per surface unit, frequent crossing of green lacewings larvae appeared and this consequently lead to cannibalism. In most cases larger, elder larv ae consumed smaller, younger larvae. Cannibalism increased with temperature rise and was the most intensive at 25 °C. At this temperature the larval mortality was 22.0 % after two days, while after four days the larval mortality reached 31.0 %V prispevku je predstavljen kanibalizem med ličinkami navadne tenčičarice (Chrysoperla carnea), ki se je pojavil pri laboratorijskem preučevanju neciljnega delovanja entomopatogenih ogorčic na ličinke omenjenega naravnega sovražnika. Najverjetnejši vzrok za pojav kanibalizma so bile premajhne petrijevke, v katerih je potekal poskus. Zaradi velikega števila ličink navadne tenčičarice na enoto površine, je prišlo do pogostega srečevanja ličink in posledično do kanibalizma. V večini primerov so ličinke višjega larvalnega stadija pojedle manjše ličinke. Kanibalizem se je povečeval z višanjem temperature in je bil najbolj intenziven pri 25 °C, kjer je bila smrtnost ličink dva dni po začetku poskusa 22,0 %, po štirih dneh pa 31,0 %

Optimisation of biomass liquefaction with glycerol and characterisation of theformed volatile products

V članku je predstavljena optimizacija utekočinjanja smrekovine, celulignina, celuloze in slame v reakcijskem topilu glicerolu ob prisotnosti H2SO4 kot katalizatorja. Optimalni čas utekočinjanja smo določali v reaktorski posodi pri temperaturi 180 °C in pri atmosferskem tlaku. Utežno razmerje med biomaso in glicerolom je bilo 1:3. Sestavo destilatov, ki so nastali med reakcijo utekočinjanja biomase, smo spremljali s plinsko kromatografijo, sklopljeno z masno spektrometrijo (GC-MS). Ugotovili smo, da je z glicerolom možno utekočiniti vse naštete tipe biomase. V destilatih smo identificirali furfural, ki lahko predstavlja temeljno substanco za sintezo najrazličnejših derivatov. S tem odpiramo novo pot učinkovitejši uporabi produktov utekočinjanja