Degradation of wood surfaces during natural weathering. Effects on lignin and cellulose and on the adhesion of acrylic latex primers

1996 ◽  
Vol 30 (6) ◽  
Author(s):  
P.D. Evans ◽  
P.D. Thay ◽  
K.J. Schmalzl
Keyword(s):  
Natural Weathering ◽  
Acrylic Latex ◽  
Wood Surfaces ◽  
Weathering Effects

scholarly journals Shelling of Growth Rings at Softwood Surfaces Exposed to Natural Weathering

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 862
Author(s):  
Lukie H. Leung ◽  
Philip D. Evans
Keyword(s):  
Growth Ring ◽  
Inverse Correlation ◽  
Natural Weathering ◽  
Woody Tissue ◽  
Growth Rings ◽  
Western Larch ◽  
Wood Surfaces

Shelling is the delamination of growth rings and the projection of woody tissue from wood surfaces. Shelling disrupts coatings and makes refinishing difficult, and a better understanding of the phenomenon is needed to help alleviate its unwanted effects. We tested whether confocal profilometry could quantify shelling in flat-faced and profiled-faced western larch deckboards exposed to natural weathering and examined the effects of growth-ring orientation and angle on shelling. Confocal profilometry was able to quantify shelling in both deckboard types. Shelling developed at the surface of flat-faced deckboards oriented pith-side-up, whereas it was absent from boards oriented bark-side-up. We found an inverse correlation between the height of shelled growth rings and the angle of growth rings to the surface of flat-faced boards. Shelling occurred in profiled-faced boards oriented pith-side-up due to the delamination of growth ring tips and projection of latewood from wood surfaces. A superficially similar although less pronounced phenomenon was seen in profiled-faced boards oriented bark-side-up. The shelling of profiled-faced boards oriented pith-side-up created lanceolate-shaped slivers of latewood that projected from the peaks of profiles. Some of these latewood tips were sharp and, for this reason, we suggest that profiled-faced western larch deckboards should always be oriented bark-side-up rather than pith-side-up.

Copper and aluminium deposition by cold-plasma spray on wood surfaces: effects on natural weathering behaviour

2016 ◽  
Vol 75 (3) ◽  
pp. 315-324 ◽  
Author(s):  
P. Gascón-Garrido ◽  
N. Mainusch ◽  
H. Militz ◽  
W. Viöl ◽  
C. Mai
Keyword(s):  
Plasma Spray ◽  
Cold Plasma ◽  
Natural Weathering ◽  
Wood Surfaces ◽  
Weathering Behaviour

scholarly journals A Method for Accelerated Natural Weathering of Wood Subsurface and Its Multilevel Characterization

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 126
Author(s):  
Anna Sandak ◽  
Jakub Sandak ◽  
Marion Noël ◽  
Athanasios Dimitriou
Keyword(s):  
Structural Damage ◽  
Structural Integrity ◽  
Degradation Process ◽  
Natural Weathering ◽  
Bordered Pits ◽  
Ft Ir ◽  
Short Time ◽  
Wood Surfaces ◽  
Kinetics Of

The function of altering weathering factors and degradation mechanisms are essential for understanding the weathering process of materials. The goal of this work was to develop a method for the acceleration of natural weathering and to investigate the molecular, microstructure and macrostructure degradation of wood caused by the process. Tests were performed in the whole month of July, which, according to previous research, is considered as the most severe for weathering of wood micro-sections. Sample appearance was evaluated by colour measurement. Scanning electron microscopy was used for evaluation of the structural integrity and changes in the microstructure of wood morphological components. Changes on the molecular level were assessed by means of FT-IR spectroscopy. Observation of the effects of weathering allowed a better understanding of the degradation process. Typical structural damage, such as cracks on bordered pits and cross-field pits, and, as a consequence, their erosion, revealed the sequence of the degradation process. It was confirmed that earlywood was more susceptible to damage than latewood. Even if the weathering test was conducted for a relatively short time (28 days) the ultra-thin wood samples changed noticeably. The progress of alteration was similar as usually noticed for wood surfaces, but occurred at shorter exposure times. The estimated acceleration factor was ×3, compare to the natural weathering kinetics of wood. The research methodology presented can be used for the determination of the weather dose-response models essential to estimate the future service life performance of timber elements.

scholarly journals Effects of Climate on Exterior Wood Coating Performance: A Comparison of Three Industrial Coatings in a Warm-Summer Mediterranean and a Semi-Arid Climate in Oregon, USA

Coatings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 85
Author(s):  
Kent Davis ◽  
Scott Leavengood ◽  
Jeffrey J. Morrell
Keyword(s):  
Wood Species ◽  
Fungal Growth ◽  
Natural Weathering ◽  
Specific Information ◽  
Timber Species ◽  
Coating Performance ◽  
Wood Coatings ◽  
Film Forming ◽  
Mass Timber ◽  
Wood Surfaces

Wood exposed in exterior applications degrades and changes color due to weathering and fungal growth. Wood coatings can reduce the effects of weathering by reducing the damaging effects of ultraviolet light, reducing water absorption, and slowing fungal growth on the surface. Coating performance depends on the blend of resins, oils, and pigments and varies considerably among different wood species and conditions. Specific information describing expected service for different wood species and exposure conditions is not commonly available; certain combinations may work well in one climate or on one timber species, but underperform elsewhere. This study compared the performance of three industrial wood coatings on two wood species for two temperate climates under natural weathering conditions. Most of the coatings/species combinations lost their protective properties within 12 to 15 months; however, fungal growth was more prevalent at the wetter site than at the drier site for several combinations. Film-forming coatings often peeled and cracked, while penetrating coatings weathered and changed color relatively uniformly during the study. While no coating was completely effective, the results illustrate the benefits of using coatings that promote the development of natural, uniform-patinaed wood surfaces. The findings also guide coating maintenance programs for mass timber structures exposed to natural weathering conditions.

scholarly journals Plasma Treatment Reduced the Discoloration of an Acrylic Coating on Hot-Oil Modified Wood Exposed to Natural Weathering

Coatings ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 248 ◽  
Author(s):  
Arash Jamali ◽  
Philip D. Evans
Keyword(s):  
Contact Angle ◽  
Plasma Treatment ◽  
Water Vapour ◽  
Natural Weathering ◽  
Water Droplets ◽  
Acrylic Paint ◽  
Acrylic Coating ◽  
Bordered Pits ◽  
Wood Surfaces ◽  
Modified Wood

We test the hypothesis that plasma-treatment will remove oil from the surface of hot-oil modified blue-stained pine wood, and improve the adhesion and outdoor performance of a white acrylic coating on the modified wood. Modified wood was treated with water-vapour plasma, and microstructural changes at wood surfaces were examined. Plasma treatment removed oil from the surface of modified wood and etched bordered pits. The contact angle of water droplets on modified wood was 91.8°, but plasma-treatment for only 33 s reduced contact angle to less than that of the unmodified control (48.6°). The adhesion of the acrylic paint to modified wood was unaffected by plasma-treatment, but the adhesion rating of coated samples tested wet was slightly lower (3.1) than that of the coating on samples tested dry (3.5). The lightness value (CIE-L) of the acrylic coating on hot-oil modified wood samples exposed outdoors for 18 months was significantly lower (darker, 65.5) than that of the coating on similarly modified and exposed samples pre-treated with plasma (75.8). We conclude that plasma-treatment shows promise as a way of removing oil from the surface of hot-oil modified wood and reducing the discolouration of an acrylic coating on modified wood exposed to natural weathering.

Organosilicone Modified Styrene-Acrylic Latex: Preparation and Crude Oil Dehydration

2018 ◽  
Vol 55 (1) ◽  
pp. 71-77 ◽  
Author(s):  
Shihong Pei ◽  
Yue Zhao ◽  
Zixu Wang
Keyword(s):  
Crude Oil ◽  
Acrylic Latex
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