The use of organo alkoxysilane coupling agents for wood preservation

Holzforschung ◽  
2004 ◽  
Vol 58 (3) ◽  
pp. 316-325 ◽  
Author(s):  
C.A.S. Hill ◽  
M.R.M. Farahani ◽  
M.D.C. Hale
Keyword(s):  
Solid State ◽  
Moisture Content ◽  
Treated Wood ◽  
Pinus Nigra ◽  
Wood Moisture Content ◽  
Wood Preservation ◽  
Wood Moisture ◽  
Weight Percentage ◽  
Weight Percentage Gain ◽  
Trimethoxy Silane

Abstract Corsican pine (Pinus nigra) sapwood was treated with methanolic solutions of two organo alkoxysilanes ([γ-(methacryloxy)propylx] trimethoxy silane (TMPS), or vinyl trimethoxy silane (VTMS)). Various treatment parameters were studied in order to determine the optimum method for obtaining a stable weight percentage gain. For TMPS, it was found that best results were obtained when a free-radical initiator was used in conjunction with the silane. This indicates that polymerisation of this species occurs via the pendant methacryloxy moeity, a result confirmed by solid-state nuclear magnetic resonance studies of the treated wood. For VTMS, wood moisture content had a profound influence upon the weight percentage gain due to treatment, with higher weight percentage gains obtained as wood moisture content was increased. This indicates that polymerisation in this case occurred via the formation of silanol groups to form siloxane linkages. Solid-state NMR confirmed that the double bond of the organo-functional group was intact after polymerisation had occurred. Modified wood samples were then prepared using optimised treatments for each silane. The wood was prepared to a variety of weight percentage gains and the effect of treatment on the dimensional stability and decay properties of the treated material studied. Treatment of Corsican pine sapwood with the two organo-alkoxy silanes, resulted in only moderate increases in dimensional stabilisation, with anti shrink efficiency values (after 5 water-soak/oven-dry cycles) no greater than 40%. Treatments were found to be relatively stable to hydrolysis. Some differences were observed in the effectiveness of the two silanes in providing protection. Full decay protection required high treatment levels with the silanes.

scholarly journals Thermal conductivity and deformation of Taxodium hybrid ‘Zhongshanshan’ during heat transfer process

BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 2645-2655
Author(s):  
Yuehua Zhu ◽  
Yaoli Zhang ◽  
Biao Pan
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Moisture Content ◽  
Transfer Process ◽  
Dimensional Change ◽  
Testing Temperature ◽  
Scientific Basis ◽  
Heat Transfer Process ◽  
Wood Moisture Content ◽  
Wood Moisture

The thermal conductivity and the deformation of wood from the Taxodium hybrid ‘Zhongshanshan’ were studied in the process of heat transfer. The results showed that the average thermal conductivity of this wood was 0.1257 W/(m·K) under the condition of 12% wood moisture content and 30 °C heat transfer temperature. When the testing temperature exceeded 0 °C, the thermal conductivity increased linearly with both temperature and wood moisture content and was affected by the moisture content of the wood. During the heat transfer process, the deformation of features caused repeated swelling and shrinkage in the longitudinal, radial, and tangential directions. The dimensional change was greatly affected by the wood’s moisture content and was less affected by the temperature. These results are of great meaning for the study of the heat transfer process of Taxodium hybrid ‘Zhongshanshan’ wood. Furthermore, it provides a scientific basis for the heat preservation effect, drying treatment, and pyrolysis treatment of Taxodium hybrid ‘Zhongshanshan’ wood for use as a building material.

scholarly journals Improving the accuracy of wood moisture content estimation in four European softwoods from Spain

2021 ◽  
Vol 30 (1) ◽  
pp. e002
Author(s):  
Juan I. Fernández-Golfín ◽  
Maria Conde Garcia ◽  
Marta Conde Garcia
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Electrical Resistance ◽  
Solid Wood ◽  
Wood Products ◽  
Wood Moisture Content ◽  
Accurate Estimation ◽  
Wood Moisture ◽  
Mathematical Functions ◽  
Measured Moisture Content

Aim of study: To obtain improved models to predict, with an error of less than ± 2.0%, the gravimetric moisture content in four different softwoods commonly present in the Spanish and European markets, based on electrical resistance measurements. This improved moisture content estimation is useful not only for assessing the quality of wood products, especially in the case of laminated products, during the transformation and delivery process, but also for accurately monitoring the evolution of moisture in wood present in bridges and buildings, which is of great importance for its maintenance and service life improvement.Area of study: The study was carried out on samples of Scots, laricio, radiata and  maritime pines of Spanish provenances.Material and methods: On 50x50x20 mm3 solid wood samples (36 per species, 9 per condition), conditioned at 20ºC (±05ºC) and 40±5%, 65±5%, 80±5% or 90±5% Relative Humidity (RH), electrical resistance and oven-dry moisture content was measured. The Samuelsson's model was fitted to data to explain the relationship between the two variables. The accuracy of the model was evaluated by the use of an external sample.Main results: With the proposed mathematical functions the wood moisture content can be estimated with an error of ±0.9% in the four species, confirming the effectiveness of this nondestructive methodology for accurate estimation and monitoring of moisture content.Research highlights: our results allow the improvement of the moisture content estimation technique by resistance-type methodologies.Keywords: Resistance-type moisture meter; species correction.Abbreviations used: MC: Moisture content; RH: relative Humidity; R: electrical resistance; RP: wood electrical resistance measured parallel to the grain; RT: electrical resistance measured perpendicular (transversally) to the grain; GM-MC: gravimetrically measured moisture content.

scholarly journals Monitoring of Beech Glued Laminated Timber and Delamination Resistance of Beech Finger-Joints in Varying Ambient Climates

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1672
Author(s):  
Hannes Stolze ◽  
Mathias Schuh ◽  
Sebastian Kegel ◽  
Connor Fürkötter-Ziegenbein ◽  
Christian Brischke ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Wood Moisture Content ◽  
Adhesive Systems ◽  
Wood Moisture ◽  
Near Surface ◽  
Finger Joints ◽  
Glued Laminated Timber ◽  
Delamination Resistance ◽  
Normative Requirements

In this study, varying ambient climates were simulated in a test building by changing temperature and relative humidity. Beech glued laminated timber (glulam, Fagus sylvatica, L.) was freshly installed in the test building and monitoring of the change in wood moisture content of the glulam resulting from the variations in climate was carried out. Subsequently, finger-jointed beech specimens were exposed to the variations in relative humidity measured in the course of the monitoring experiment on a laboratory scale, and thus an alternating climate regime was derived from the conditions in the test building. Its influence on the delamination of the finger-joints was evaluated. In addition, it was examined whether beech finger-joints using commercial adhesive systems fulfil the normative requirements for delamination resistance according to EN 301 (2018) and whether different bonding-wood moisture levels have an effect on the delamination of the finger-joints. In the context of the monitoring experiment, there was a clear moisture gradient in the beech glulam between the inner and near-surface wood. The applied adhesive systems showed almost the same delamination resistance after variation of relative humidity. The normative requirements were met by all PRF-bonded and by most PUR-bonded beech finger-joints with higher bonding wood moisture content.

scholarly journals Comparison of Parallel Dowel-Bearing Strength of Mengkulang, Kempas and Pine Glulam between ASTM D 5764-97a and BS EN 383: 2007

2018 ◽  
Vol 7 (3.11) ◽  
pp. 206
Author(s):  
Nor Jihan A. Malek ◽  
Rohana Hassan ◽  
Azmi Ibrahim ◽  
Hussein M. H. Almanea ◽  
Tee H. Hean
Keyword(s):  
Moisture Content ◽  
Strength Test ◽  
Wood Moisture Content ◽  
Timber Species ◽  
Wood Moisture ◽  
Bearing Strength ◽  
Significant Parameter ◽  
Different Types ◽  
Wood Grain ◽  
Bolt Diameter

Dowel-bearing strength is a significant parameter for designing wood connection. The strength of timber connection can be influenced by the bolt diameter, wood grain direction either parallel or perpendicular, thickness of wood, moisture content and other parameters. The dowel-bearing strength test was conducted with a 12 mm bolt diameter dowel, for three different types of timber species, which were mengkulang (Heritiera sp.), kempas (Koompassia malaccensis) and pine (Pinus sp.) glulam. The dowel was placed parallel to the timber grain direction with a glue line at the center of the half-hole test. The 5% diameter offset load (F5%) for dowel-bearing strength (Fy) was determined by using the ASTM D 5764-97a whereas the dowel-bearing strength (Fh) was determined based on BS EN 383: 2007. The results of the three different types of wood showed that the Malaysian timber kempas and mengkulang were 51.740% and 32.966%, respectively, which were higher than the European timber pine. The results of the dowel-bearing strengths (Fh), which were based on the BS EN 383: 2007 gave higher values compared to ASTM D 5764-97a.  

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