Improving impregnation properties of fir wood to acid copper chromate (ACC) with microwave pre-treatment

Abstract

© iForest -Biogeosciences and Forestry IntroductionSpecies with low wood permeability, such as fir (Abies alba L.), cause many problems during the wood impregnation process with preservatives. Fir is a gymnosperm species with torus margo pit membrane; the low permeability is mainly due to the pit aspiration during drying. Different modification methods, such as steaming, mechanical incising, drilling techniques and bio-incising were tested to improve the impregnation properties of such refractory wood species (Schwarze et al. 2006, Lehringer et al. 2009, Dashti et al. 2012a. Microwave (MW) radiation is an innovative method to increase the wood permeability and thus to improve the preservative penetration in the wood of various species (Vinden et al. 2003, Brodie 2009, Torgovnikov & Vinden 2009, Dashti et al. 2012b). Due to the high efficiency in converting electricity into microwave radiation, energy saving, in-depth heating of materials and reduced costs, microwave pretreatment is spreading in many industries (Torgovnikov & Vinden 2010). The increasing effect of microwave radiation on the wood permeability was reported to be due to changes in the wood porous structure (Lu et al. 1994, Zhao et al. 1998, Yu et al. 2002. Torgovnikov & Vinden (2009) mentioned that when the microwave energy was applied to wood, the steam pressure generated within the wood cells provokes the rupture of the pit membranes on cell walls and the weak ray cells, allowing an easier fluid transfer. Liu et al. (2005) reported that the permeability of larch wood can be improved without noticeable reduction in the strength and stiffness if the conditions of microwave pretreatment were optimized. Treu & Gjolsjo (2008) also reported that the microwave processing of Norway spruce (Picea abies L.) caused a significant increase in the uptake of a 2% copper-based preservative after wood modification by microwave energy of more than 50 kWh/m 3 at a frequency of 2.45 GHz. Hong-Hai et al. (2005) also found that the water uptake of Larch (Larix olgensis) wood irradiated by microwave was 2.5 to 3.3 times greater than that of non-radiated wood. Dashti et al. (2012b) found that the microwave radiation of fir wood (Abies alba L.) at frequency of 2.45 GHz for 7 and 10 minutes can increase the wood radial permeability. They also reported that the torus of some bordered pits was hydrolyzed due to the microwave radiation; however, they did not study the relationship of MW pre-treatment on the amount of preservative uptake, depth of penetration, or other impregnation properties. This species is vastly grown in different parts of the world and therefore provide a continuous raw material for commercial applications; huge amount of fir lumbers are also imported to Iran on a regular basis to satisfy the growing needs for commercial woods. Because of the importance of fir species in timber industry and its various applications, the present research was carried out to evaluate the effects of microwave radiation conditions on the impregnation properties of fir wood (Ab...

Effect of microwave treatment on air permeability and preservative impregnation of Eucalyptus tereticornis wood

“…The results showed that the coefficient of specific permeability increased by up to 159 % in comparison with untreated samples. An improved impregnation property of fir wood to acid copper chromate (ACC) with microwave pre treatment has been reported by Ramezanpour et al (2014). Torgovnikov and Vinden (2000) also reported improved permeability of less permeable hardwoods after microwave irradiation.…”

Quantitative evaluation of microwave irradiation on short-rotation plantation wood species

“…Previous studies revealed that improvement of preservative retention in wood is directly proportional to the applied MW energy and results in increase in retention values (Ramezanpour et al 2015, Ganguly and Tripathi 2018, Samani et al 2019. MW modified wood samples were dipped in the preservative solution immediately after irradiation so as to simulate the vacuum process in the full cell method and assess its effect in preservative retention.…”

Bazı Jeotermal Sularla Muamele Edilmiş Kızılçam Odununun Yoğunluk, Eğilme Direnci ve Elastikiyet Modülü: Konya Bölgesinden Bir Çalışma

“…Sarıçam odununda ED'ni bor katkılı yağ %0.22 [37], amonyumsulfat %48, diamonyumfosfat %5 ve borik asit %30 azaltırken, CBC %15 ve boraks %12 arttırdığı rapor edilmiştir [11]. Kavak odununda ED'ni %10'luk reçine %8 arttırırken, %2'lik silisyumdioksit %5 azalttığı [13], buna karşılık nanoalüminyumoksitin EEM, ED ve liflere pararlel basınç direncinde artış sergilediği ifade edilmektedir [40]. Kore çamı ED'ni amonyumfosfatın %14.4 azalttığı rapor edilmiştir [37].…”