TV regimes were chosen to repeat m ass loss of 1600.8W TT (2142.0TV), as well as to have 2 more (2173.0TV) and 2 (2042.0TV) less mass l oss.Learn more Cite this publication Anete Meija 9.48 BM Certification Ignazia Cuccui 15.94 Italian National Research Council 1 Ilze Irbe 21.28 Latvian State institute of Wood chemistry Andris Morozovs 6.86 Latvia University of Agriculture Show more authors Hide Abstract Thermally modified birch (Betula pendula Roth) veneers that had been subjected to wood treatment technology (WTT) or thermo vacuum (TV) processes were compared in this study.After modification of veneers in the range of temperatures from 160 C to 218 C and times from 0.5 h to 3 h, the color, mass loss, density, tensile strength, hygroscopicity, and decay resistance against brown rot fungus Coniophora puteana were determined.Treatment regimes with the greatest mass loss were at 217 C for 3.0 h in TV (7.8) and 160 C for 0.8 h in the WTT (6.7).
As expected, wood mass loss correlated well with moisture exclusion efficiency (MEE) in all relative humidity (RH) environments (r 0.95 to 0.99). Strength loss in the WTT was considerable compared to the TV process (57 and 40, respectively). The resistance against brown rot fungus was moderate with a mass loss of 12 to 33. Among the investigated samples, the regime 2173.0TV showed the best resistance against brown rot fungus and acceptable other properties. Roth Vacuum Technology Free Advertisement ContentRoth Vacuum Technology For Free Advertisement ContentDiscover the worlds research 17 million members 135 million publications 700k research projects Join for free Advertisement Content uploaded by Anete Meija Author content All content in this area was uploaded by Anete Meija on Apr 15, 2020 Content may be subject to copyright. After modification of veneers i n the range of temperatures from 160 C to 218 C and times from 0. Coniophora pu teana were determined. Treatment regimes with the greatest mass loss were at 217 C for 3.0 h i n TV (7.8) and 160 C f or 0.8 h in the W TT (6.7). As expected, wood mass loss correlated we ll with moisture exclusion efficiency (MEE) i n all relative humidity (RH) environments (r 0.95 to 0.99). Strength l oss in t he WTT w as considerable compared to the TV process ( 57 and 40, respectively). The longer t he wood material can be used, the l onger it stores carbon; therefore several techniques to prolong the life span of wood materials have been developed (Hildebrandt et al. Plywood is an engineered cross-glued wood material made from peeled veneers. World production of ply wood reached 107.4 milli on m 3 in 2017 (Raute 2017). The properties of plywood are m ainly determined by the characteris tics of veneers such as wood species and t echnological features (Gil bert et al. ![]() Roth Vacuum Technology Trial Method ForWood thermal treatment at temperatures of 160 C to 240 C is the m ost acceptable industrial method for wood modification. The wood t hermal modification increases the dimensional stability of veneer by increas ing its hydrophobicity. Chemical changes in wood due to the therm al m odification depend on the duration of treatm ent and temperature. If t hese decomposition products are promptly e vacuated by va cuum, the process l owers woo d degradation (Candelier et al. San dak et al. 2016). Sev eral commercial processes use vac uum, such as Silvapro (Rep et al. Sm artHeat (Van Acker et al. Termovuoto (Ferrari et al. Silver birch is a widely used woo d species in Latvia for plywood a nd furniture manufacturing as well as a raw material for t he pulp and paper industry; it has limited biological durability and dimensional stability. By decreasing the drawbacks, the usage of silver birch c ould b e widen ed, and t hermal t reatment i s a m ethodology that increases biological durabili ty and dimensional stabili ty. Silver bi rch has been treated i n W TT process (Grinins 2016) but has not been widely investigated in the thermo-vacuum (TV) process. The objective of the present rese arch is the comparison of thermally modified ( Betula pendula Roth) veneers treated i n the WTT and TV processes. EXPERIMENTAL Materials and Methods The experiments were carried o ut in the Laboratory of Wood Drying and Thermal Treatment at the BioEconomy Institute CNR IBE, San Michele all Adige, Italy (TV modification and moisture exclusion e fficiency), the Laboratory of Wood Biodegradation and Prot ection of the Latvian State Institute of Wood Chemistry (WTT, microscopy and decay t ests), and the Department of Wood Processing in L LU. Experiments were conducted with rotary-cut birch veneers from JSC Latvijas Finieris, Riga, Latvia. Wood treatment technology (WTT) Thermal modification of birch veneers with the dimensions of 1000 m m 350 mm 1.5 m m was conducted wi th wood treatment techn ology under the previ ously determined optimal regime of 160 C, 0.8 h (1600.8W TT), and 500 kPa to 900 kPa pressure in water vapor environments in packs of 10 sheets per each. The process classified as a moist, closed thermal tr eatment technology was described in detail previously by Grinins et al. Thermo vacuum technology (TV) Thermo va cuum technology (TV) can be classified as a dry, open thermal treatment under vacuum (Allegretti et al. Sandak e t al. 2015). Rotary cut 600 mm 600 mm 1.5 mm birch veneers were treated in four experimental regimes (Table 1) under 25 kPa pressure, although this pro cess was m odified s o that ven eers were treated under a.
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