Summary
Radiata pine veneers and blocks were exposed to natural weathering under Australian summer conditions over a period of 30 days. Infrared spectroscopy revealed that there was perceptible surface delignification after 4 hours exposure, substantial surface delignification after 3 days exposure and almost complete surface delignification after 6 days. Rapid lignin degradation was also suggested by measurements of the acid insoluble lignin content of weathered veneers. Viscometry determinations on holocellulose samples from weathered veneers and unweathered controls indicated significant depolymerisation of cellulose after 4 days exposure. A tape test was used to assess the adhesion of acrylic latex primers to weathered blocks. The adhesion of exterior acrylic primers decreased on weathered wood surfaces and was significantly lower on specimens that were weathered for 5 to 10 days. An oil-modified acrylic primer showed greater adhesion to weathered wood surfaces. Primer adhesion was lower on weathered radial surfaces than on similarly exposed tangential surfaces. The practical implications of these findings for the coating of exterior wood with acrylic latex primers are discussed briefly.
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References
Ashton, H. E. 1967: Clear finishes for exterior wood. Field exposure tests. J. Paint Technol. 39: 212–224
ASTM 1976: Standard methods for measuring adhesion by tape test. American National Standard D3359, 661–664, Philadelphia, ASTM
Boxall, J. 1977: Painting weathered timber. Buildg. Res. Est. (UK) Information Sheet. 20/77: 1–2
Browne, F. L. 1960: Wood siding left to weather naturally. Southern Lumberman. 201: 141–143
Browning, B. L. 1967: Methods of wood chemistry. Vol. 2, Chap. 19, pp. 394–408, Chap. 32, pp. 726–727. New York: John Wiley
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-Werkst. 39: 341–350
Desai, R. L. 1967: Coating adhesion to weathered wood. Can. Dept. Fisheries and Forestry. Bi-monthly Res. Notes 23: 36–37
Evans, P. D. 1988: A note on assessing the deterioration of thin wood veneers during weathering. Wood Fiber Sci. 20: 487–492
Evans, P. D. 1989: Structural changes in Pinus radiata during weathering. J. Inst. Wood Sci. 11: 172–181
Evans, P. D.; Michell, A. J.; Schmalzl, K. J. 1992: Studies of the degradation and protection of wood surfaces. Wood Sci. Technol. 26: 151–163
Evans, P. D.; Schmalzl, K. J. 1989: A quantitative weathering study of wood surfaces modified by chromium VI and iron III compounds. Part 1. Loss in zero-span tensile strength and weight of thin wood veneers. Holzforschung. 43: 289–292
Evans, R.; Wallis, A. F. A. 1995: Personal communication
Feist, W. C.; Hon, D. N.-S. 1984: Chemistry of weathering and protection. In: Rowell, R. M. (Ed). Chemistry of Solid Wood, Chap. 11, pp 401–451. Wash. D.C.: A.C.S.
Harrington, K. J.; Higgins, H. G.; Michell, A. J. 1964: Infrared spectra of Eucalyptus regnans F. Muell and Pinus radiata D. Don. Holzforschung. 18: 108–113
Ifju, G. 1964: Tensile strength behavior as a function of cellulose in wood. For. Prod. J. 14: 366–372
Kalnins, M. A. 1966: Surface characteristics of wood as they affect the durability of finishes. Part 2, Photochemical degradation of wood. U.S. For. Prod. Lab. Report 57: 23–60
Kuo, M.-L.; Hu, N. 1991: Ultrastructural changes of photodegradation of wood surfaces exposed to UV. Holzforschung. 45: 347–353
Miniutti, V. P. 1964: Preliminary observations. Microscale changes in cell structure at softwood surfaces during weathering. For. Prod. J. 14: 571–576
Miniutti, V. P. 1967: Microscopic observations of ultraviolet irradiated and weathered softwood surfaces and clear coatings. U.S. For. Serv. Res. Pap. FPL 74: 1–32
Owen, J. A., Owen, N. L.; Feist, W. C. 1993: Scanning electron microscope and infrared studies of weathering in Southern pine. J. Mol. Structure 300: 105–114
Richter, G. A. 1935: Relative permanence of papers exposed to sunlight II. Ind. Eng. Chem. 27: 432–439
TAPPI 1989: Viscosity of pulp (capillary viscometer method). Technical Assoc. Pulp & Paper Industry Official Test Method T 230 om-89
Thay, P. D. 1993: The adhesion of primers to pre-weathered wood. M.Sc. thesis, The Australian National University
Underhaug, A.; Lund, T. J.; Kleive, K. 1983: Wood protection — the interaction between substrate and product and the influence on durability. J. Oil & Col. Chem. Assoc. 66: 345–350
Williams, R. S.; Feist, W. C. 1993: Durability of paint or solid-color stain applied to preweathered wood. For. Prod. J. 43: 8–14
Williams, R. S.; Winandy, J. E.; Feist, W. C. 1987: Paint adhesion to weathered wood. J. Coat. Technol. 59: 43–49
Williams, R. S.; Plantinga, P. L.; Feist, W. C. 1990: Photodegradation of wood affects paint adhesion. For. Prod. J. 40: 45–49
Zavarin, E.; Cool, L. G.; Jones, S. J. 1991: Analysis of solid wood surfaces by internal reflection Fourier transform infrared spectroscopy (FTIR-IRS). J. Wood Chem. Tech. 11: 41–56
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The authors wish to thank Dr. A. J. Michell for FTIR spectral determinations and the Australian Research Council small grants scheme for financially supporting part of the work
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Evans, P.D., Thay, P.D. & Schmalzl, K.J. Degradation of wood surfaces during natural weathering. Effects on lignin and cellulose and on the adhesion of acrylic latex primers. Wood Sci.Technol. 30, 411–422 (1996). https://doi.org/10.1007/BF00244437
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DOI: https://doi.org/10.1007/BF00244437