Abstract
This paper demonstrates that the measurement of loss of microtensile strength of thin Scots pine sapwood strips exposed to solar radiation is a consistent and reliable means of determining photodegradation rates for wood. Careful selection and preparation of material is shown to be effective in reducing levels of variability. Photodegradation rates obtained by exposure to natural weathering are compared with rates obtained by exposure to artificial weathering in three different artificial weathering machines. Artificial weathering is shown to be a valid means of representing natural weathering and can provide the basis for the systematic investigation of the mechanisms of photodegradation. The results indicate the spectral distribution of the radiation output of the lamp and the moisture conditions during exposure are important influences on degradation rates.
Zusammenfassung
Diese Arbeit zeigt, daß die Mikro-Zugfestigkeitsprüfung eine geeignete und zuverlässige Methode ist, um die Abbaurate des Holzes beim lichtinduzierten Abbau zu messen. Durch sorgfältige Probenauswahl kann die Fehlerbreite verringert werden. Die Abbauraten bei natürlicher und künstlicher Bewitterung mit drei verschiedenen Apparaturen wurden verglichen. Die künstliche Bewitterung kann den natürlichen Prozeß simulieren und erlaubt, somit die Untersuchung der Abbaumechanismen. Die spektrale Verteilung der benutzten Strahler und die Feuchtegehalte während der Bewitterung beeinflussen sehr stark die Abbauraten.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Anderson, E. L.; Pawlak, Z.; Qwen, N. L.; Feist, W. C. 1991: Infrared studies of wood weathering. Appl. Spectroscopy 45 (4): 641–647
Arnold, M; Lemaster, R. L.; Dost, W. A. 1992: Surface characterisation of weathered wood using a laser scanning system. Wood Fib. Sci. 24 (3): 287–293
Borgin, K. 1971: The mechanism of the breakdown of the structure of wood due to environmental factors. J. Inst. Wood Sci. 5 (4): 26–30
Boxall, J. 1977: Painting weathered timber. Building Research Establishment Information Sheet IS 20/77
Davis, A.; Deane, G. H. W.; Gordon, D.; Howell, G. V.; Ledbury, K. J. 1976: A world-wide program for the continuous monitoring of solar UV radiation using poly (phenylene) oxide film and a consideration of the results. J. Appl. Pol. Sci 20: 1165–1174
Derbyshire, H.; Miller, E. R. 1981: The Photodegradation of wood during solar irradiation. Part 1. Effects on the structural integrity of thin wood strips. Holz Roh-Werkstoff 39: 341–350
Evans, P. D.; Banks, W. B 1988: Degradation of wood surfaces by water. Changes in the mechanical properties of thin wood strips. Holz Roh-Werkstoff 46 (11): 427–435
Evans P. D. 1992: Rapid loss of lignin at wood surfaces during natural weathering. Doc. IRG/WP/2390-92. IRG Secretariat, Stockholm
Hon, D. N.-S.; Minemura, M. 1991: Colour and Discolouration. In: Wood and Cellulosic Chemistry. Marcel Dekker Inc. Ch. 9. 395–454
Horn, B. A.; Qiu, J.; Owen, N. L.; Feist, W. C. 1992: FT-IR studies of weathering effects in Western red cedar and Southern pine. In: Chemical modification of lignocellulosics, FRI Bull 176, 7–8 November, Rotorua, New Zealand
Kalnins, M. A.; Knaebe, M. T. 1992: Wettability of weathered wood. J Adhesion Sci. Tech. 6 (12): 1325–1330
Kalnins, M. A.; Feist, W. C. 1993: Increase in wettability of wood with weathering. Forest Prod. J. 43 (2): 55–57
Kleive, K. 1986: Paint failures on weathered wood. J. Coatings Tech. 58 (740): 39
Law, K. N.; Garceau, J. J.; Koran, Z. 1977: Measurement of intraincrement tensile strength by using a zero span technique. Wood Sci. 10(1): 42–48
Law, K. L.; Koran Z 1979: Microtensile strength of white spruce wood — a new approach. Wood Sci. 11 (4): 221–226
Michell, A. J. 1993: FTIR spectroscopic studies of the reactions of wood and of lignin model compounds with inorganic agents. Wood Sci. Tech. 27: 69–80
Miniutti, V. P. 1967: Microscopic observations of ultraviolet irradiated and weathered softwood surfaces and clear coatings. US Forest Service Research Paper FPL 74
Moon, P. 1940: The solar constant. J. Franklin Inst. 30: 584–617
Raczkowski, J. 1980: Seasonal effects on the atmospheric corrosion of spruce micro-sections. Holz Roh- Werkstoff 38: 231–234
Sell, J.; Wälchli, O. 1969: Changes in the surface texture of weather exposed wood. Material und Organismen 4 (2): 81–87
Williams, R. S.; Plantinga, P. L.; Feist, W. C. 1990: Photodegradation of wood affects paint adhesion. Forest. Prod. J. 40 (1): 45–49
Williams, R. S.; Feist, W. C. 1993: Durability of paint or solid-color stain applied to preweathered wood. Forest Prod. J. 42 (1): 8–14
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Derbyshire, H., Miller, E.R. & Turkulin, H. Investigations into the photodegradation of wood using microtensile testing. Holz als Roh-und Werkstoff 53, 339–345 (1995). https://doi.org/10.1007/s001070050103
Issue Date:
DOI: https://doi.org/10.1007/s001070050103