Influence of Wood Extractives on Moisture Sorption and Wettability of Red Oak (Quercus Rubra), Black Cherry (Prunus Serotina), and Red Pine (Pinus Resinosa)

Red oak (Quercus rubra), black cherry (Prunus serotina), and red pine (Pinus resinosa) wood samples were soxhlet extracted with various combinations of organic solvents including ethanol, toluene, and water according to ASTM 1110-96, ASTM D1107-96, TAPPI T207 OM-88 and TAPPI T204 om-88 standards.Contact angle and sorption isotherms of extracted and unextracted specimens were determined to evaluate the role of wood extractives on the wettability and sorption properties of these wood species.Extracted specimens adsorbed more water than unextracted specimens at high relative humidity in agreement with the literature. The contact angle decreased with increased extraction due to the removal of hydrophobic extractives. However, the absorption rate of water, estimated as the decrease in contact angle over time suggests physical modification of the wood surface by solvent extraction due to the migration and redistribution of hydrophobic extractives

Interaction of Copper-Amine With Southern Pine: Retention and Migration

The retention and leachability of copper in copper-amine (Cu-EA)-treated southern pine (SP) are influenced by the formulation and the composition of copper-amine treating solutions. The sources of copper used, Cu(OH)2, CuCO3, CuSO4, and Cu(NO3)2, in the copper-amine complex formulation affect the leachability of copper. Data show that copper-amine from CuSO4- and Cu(NO3)2-treated wood has less copper loss during laboratory water leaching than that from Cu(OH)2- and CuCO3-treated wood. Increasing the amine-to-copper molar ratio increases the copper retention by wood, but reduces the leach resistance of copper. The nature of amine ligands, such as monoethanolamine (primary amine), 2-methylamino-ethanol (secondary amine), and N, N-dimethyl-ethanolamine (tertiary amine), has some effect on copper retention and copper leaching. As the molecular weight of amine ligands increases, copper loss during leaching decreases

Ultraviolet Spectrophotometry and Fourier Transform Infrared Spectroscopy Characterization of Copper Naphthenate

Ultraviolet-Visible (UV-VIS) spectrophotometry and Fourier Transform Infrared (FTIR) spectroscopy were used to characterize copper naphthenate (Cu-N) complex in treating solution and in Cu-N treated wood. At wavelength 680 ± 2 nm, the absorption was proportional to the amount of Cu-N present in solution. FTIR was used to confirm the presence of the carboxylate group in the Cu-N complex and the carboxylic acid in the non-complexed naphthenic acid (NA). Toluene was used to extract Cu-N from treated wood for UV-vis quantitative analysis. This method can be applicable to the determination of Cu-N in solution and in treated wood with detection limits ranging from 4 to 80 ppm

Surface Tension and Wettability of CCA-Treated Red Maple

The wetting properties of untreated, water-extracted and chromated copper arsenate (CCA)-treated red maple were characterized by contact angle measurements. Conventional experimental and mathematical modeling were employed to evaluate the wetting parameters. Zisman's critical surface tensions, and both acid-base (γABs) and acid (γ+s) components of surface tension for CCA-treated wood do not differ much from those of untreated wood. After CCA-treatment, the dispersion (γds) and Lifshitz-van der Waal (γLWs) components of the surface tension increase while the polar (γps) and base (γ-s) components decrease. The high contact angles resulting from the water and CCA treatment of wood compared to untreated wood suggest poor wettability. CCA-treated wood wetted with phenol-formaldehyde (PF) adhesive gave contact angles greater than 90°, i.e., very poor wettability and the time to reach an equilibrium contact angle was three times longer than that for untreated wood

Chemical Investigation of 23-Year-Old CDDC-Treated Southern Pine

The effect of 23 years' exterior exposure on copper dimethyl dithiocarbamate (CDDC)-treated southern yellow pine was evaluated by the application of solid state analytical instrumentation. Analytical methods including environmental scanning electron microscopy (ESEM), energy dispersive X-ray analysis (EDXA), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), inductively coupled plasma (ICP), and atomic absorption spectroscopy (AAS) were used to study CDDC-treated wood. Data from ICP and AAS analysis indicated that about 60% of copper and 81% of sodium dimethyl dithiocarbamate (SDDC) are lost from the 1/8-in. shell of the below-ground portion of the stakes after 23 years' field exposure. The molar ratio of SDDC to copper for freshly treated southern yellow pine is 2:1, while it is reduced to 1:1 after 23 years' field exposure. ESEM micrographs and EDXA data confirm the presence of solids rich in copper and sulfur similar to that of CDDC freshly treated samples. It is suggested that bidentate CDDC is modified to monodentate and bonded to wood to balance the available valence

Photoprotection of Copper-Amine-Treated Pine

Phenolic UV absorbers containing 2-[(2"-benzotriazinyl)-4'-hydroxy-5'-tert-butylphenyl]ethyliso-cyanate (HBTNCO) and isocyanates of monosubstituted polyethylene glycol (350) as PEGNCO, and commercial Tinuvin 1130 (T1130) and Tinuvin precursor (PT1130) were evaluated for protection of copper-amine treated maritime pine against photodiscoloration. Treated wood was irradiated with UV (ultraviolet) light from a pressure mercury lamp of 400 watts for various periods of time. The color change after irradiation was estimated by using the CIELAB system. Grafting of HBTNCO+PEGNCO to wood surfaces using microwaves provided relatively good protection against discoloration

Diffuse Reflectance Infrared Fourier Transform Spectroscopy (Drift) and Color Changes of Artificial Weathered Wood

Short-term (22.7 h) accelerated weathering was performed on black cherry (Prunus serotina), soft maple (Acer saccharinum), and red oak (Quercus rubra) using a 2-h ultraviolet (UV) light irradiation and 0.3-h water spray regime. Contributions to the wood surface color change from changes in lightness, chroma, and hue were observed, and variations existed among wood species. Chemical modifications on wood surfaces were monitored semi-quantitatively by using Diffuse Reflectance Infrared Fourier Transform spectroscopy (DRIFT). Band intensities at 1170 cm-1, 1510 cm-1, and 1740 cm-1 were used to follow the photodegradation on the wood surface during the 22.7-h accelerated weathering. Linear correlation was observed between the ratio of band intensity at 1740 cm-1 relative to the band intensity at 1170 cm-1, and the color change or the lightness modification. Results from this study clearly indicated that the rates of weathering/photodegradation of wood are influenced by wood species. Soft maple and red oak exhibit similar weathering rate (0.048) and higher than that of black cherry (0.031)

Bending Creep Behavior of Medium Density Fiberboard and Particleboard During Cyclic Moisture Changes

Bending creep behavior of four types of medium density fiberboard (MDF) and two types of particleboard during cyclic moisture changes was investigated in this study. Tests were made at 20°C with three cyclic relative humidity changes between 65% and 95% under the 10% short-term breaking stress. The effect of moisture content (MC) change on initial compliance and mechano-sorptive (MS) compliance was examined. The results indicated that relative deflection and total compliance of the samples increased over the history of cyclic moisture changes, and their magnitudes varied with board types. Melamine- and phenol-resin bonded boards had smaller relative deflection and total compliance than did urea-resin bonded boards. Both relative deflection and total compliance increased in adsorption and showed reduction in desorption. Initial compliance followed a linear relation with MC and had some influence on total compliance behavior under moisture cycles. MS compliance increased in adsorption while showing slight reduction or increase in desorption. The first adsorption led to the largest MS compliance, followed by subsequent adsorption. With increasing MC change, MS compliance increased linearly in the first adsorption, while it increased nonlinearly in the subsequent adsorption. The MS compliance coefficient KM was product-dependent. Resin type appeared to be an important factor influencing the variations in KM. In this study, urea-resin bonded boards had a greater KM compared to melamine- and phenol-resin bonded boards

The Effect of Post-Steaming on Copper Naphthenate-Treated Southern Pine

The reduction of copper from cupric (Cu2+) to cuprous (Cu1+) form in post-steamed copper naphthe-nate-treated southern pine was monitored. The amount of cuprous oxide formed after the post-steam treatment was determined by X-ray diffraction (XRD). About 50% of copper was reduced from cupric to cuprous in post-steamed samples treated to a retention of 0.31 to 0.51% total copper. Less than 15% of the copper was reduced to cuprous in the post-steamed samples containing 0.71% total copper. Environmental scanning electron microscopy (ESEM) was used to collect images of the crystalline cuprous oxide deposits on the wood cell walls

Laboratory Evaluation of Natural Decay Resistance and Efficacy of CCA-Treated Rubberwood (Hevea brasiliensis Muel!. Arg.)

Information on the natural decay resistance and efficacy of CCA-treated rubberwood is important for the development rubberwood industry. The purpose of this study was to determine the natural decay resistance of rubberwood and the efficacy of CCA-pressure treatment in order to explore a new opportunity for this abundant raw material. Natural decay resistance and efficacy of CCA was estimated using soil-block test according to AWPA ElO-91. Cubes were exposed to six wood-decay fungi: two each from white, brown, and soft rot. The moisture content of test cubes exposed to /rpex lacteus and Trametes versicolor increased with weight loss increase, while that exposed to Gloeophyllum trabeum and Postia placenta decreased. After a 12-week incubation period the average weight loss by white rot and brown rot fungi was about 1.5 times higher than that of soft rot fungi. CCA retention of 4.1 kg/m3 reduced weight loss to between 8 % and 10 %, retention of 14.5 kg/m3 protected weight loss by all test fungi from exceeding2%