Light-Induced Colour Changes in Wood Surfaces in Indoor Conditions Determined by an Artificial Accelerated Test: Influence of Wood Species and Coating Materials
Source abstract
Abstract
Stabilising the natural colour of wood species exposed to light in indoor conditions is a challenge that could be better addressed based on a deeper understanding of the occurring phenomena and influencing factors. This paper investigates comparatively the light-induced colour changes for three hardwood species, namely, European maple (Acer pseudoplatanus L.), European ash (Fraxinus excelsior L.) and European walnut (Juglans regia L.), as well as the influence of finishing with three types of clear, colourless waterborne lacquers: acrylic-polyurethane (F1), acrylic (F2) and polyurethane (F3) on their colour stability. Colour measurements in the CIELab system in conjunction with an artificial accelerated ageing test under the action of UV-VIS radiation, simulating natural light passing through window glass, and two types of test samples were employed to highlight the influence and contributions of the wood substrate and of the coating films to the global colour modifications. Coating films applied on 1 mm clear glass slides were employed as a sort of “detachable” finish for this purpose. Direct exposure to UV-VIS light caused visible colour changes for both uncoated and coated wood surfaces, the values of the calculated colour differences (ΔE) after a 72 h exposure being dependant on both the wood species and the coating material. Excepting two situations for walnut, statistically significantly higher colour differences were obtained for the uncoated samples: maple (9.36 units), ash (8.39 units), walnut (6.20 units), compared to the coated ones: maple (4.92–5.71 units), ash (2.25–3.94 units), walnut (4.74–7.70 units). The wood substrates underlying the coating films were found to bring the maximum contribution to the overall colour changes in the clear coated surfaces, while the coating films employed in this research demonstrated a fairly good colour stability to UV-VIS light exposure, with maximum colour changes (∆E) up to only 1.30 units. Overall, the wood species and the type of coating were found as influencing factors in interaction with the light-induced colour changes in wood surfaces in indoor conditions.
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Research context
OpenAlex topics: Dyeing and Modifying Textile Fibers · Cultural Heritage Materials Analysis · Color perception and design
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
Faculty of Furniture Design and Wood Engineering (FDMIL), Transilvania University of Brașov, 500036 Brasov, Romania
Funding
budget funded Ph.D. research project undertaken by the principal author within the Doctoral School of the Transilvania University of Brașov-Romania.
References (64)
Show source-provided references
1. Wood surface discolouration due to simulated indoor sunlight exposure10.1007/s00107-007-0201-9 ↗
2. Natural, Accelerated, and Simulated Weathering of Wodd: A Review10.15376/biores.15.4.Kropat ↗
3. Spear, M.J., Curling, S.F., Dimitriou, A., and Ormondroyd, G.A. (2021). Review of Functional Treatments for Modified Wood. Coatings, 11.10.3390/coatings11030327 ↗
4. Rajkovic, J.V., and Miklecic, J. (2021). Enhancing Weathering Resistance of Wood—A Review. Polymers, 13.10.3390/polym13121980 ↗
5. Blanchet, P., and Pepin, S. (2021). Trends in Chemical Wood Surface Improvements and Modifications: A Review of the Last Five Years. Coatings, 11.10.3390/coatings11121514 ↗
6. Role of α/γ Fe2O3 and ZnO nano-particles in reducing photodegradation of wood components10.1007/s00226-023-01456-8 ↗
7. Surface Discoloration of Ultraviolet (UV)-Irradiated Phyllostachys bambusoides Bamboo10.5658/WOOD.2023.51.3.173 ↗
8. Gruyter, W.D. (1985). Wood—Chemistry, Ultrastructure, Reactions, Walter de Gruyter.
9. Yellowing and IR-changes of spruce wood as result of UV-irradiation10.1016/S1011-1344(02)00412-8 ↗
10. Photodegradation and photostabilisation of wood—The state of the art10.1016/j.polymdegradstab.2004.10.018 ↗
11. Williams, R.S. (2023, September 08). Weathering of Wood, Handbook of Wood Chemistry and Wood Composites, Available online: https://www.fs.usda.gov/research/treesearch/22122.
12. Evans, P., Chowdhury, M., Mathews, B., Schmalzl, K., Ayer, S., Kiguchi, M., and Kataoka, Y. (2005). Handbook of Environmental Degradation of Materials, William Andrew Inc.
13. Structural Changes in Wood under Artificial UV Light Irradiation Determined by FTIR Spectroscopy and Color Measurements—A Brief Review
14. Violet light causes photodegradation of wood beyond the zone affected by ultraviolet radiation10.1515/HF.2007.005 ↗
15. Spectral sensitivity in the photodegradation of fir wood (Abies alba Mill.) surfaces: Colour changes in natural weathering10.1007/s00226-013-0601-4 ↗
16. Surface Investigation of Photo-Degraded Wood by Colour Monitoring, Infrared Spectroscopy, and Hyperspectral Imaging10.1155/2013/380536 ↗
17. UV light impact on ellagitannins and wood surface colour of European oak (Quercus petraea and Quercus robur)10.1016/j.apsusc.2006.11.005 ↗
18. Influences of extractives on the photodegradation of wood10.1016/j.polymdegradstab.2009.12.024 ↗
19. Stabilizing effect of extractives on the photo-oxidation of Acacia confusa wood10.1016/j.polymdegradstab.2010.06.012 ↗
20. Study on inhibition mechanisms of light-induced wood radicals by Acacia confusa heartwood extracts10.1016/j.polymdegradstab.2014.03.036 ↗
21. Novel color stabilization concepts for decorative surfaces of native dark wood and thermally modified timber10.1016/j.porgcoat.2015.06.017 ↗
22. Wood surface discolouration of three hungarian hardwood species due to simulated indoor sunlight exposure
23. Comparative study of photodegradation of six wood species after short-time UV exposure10.1007/s00226-015-0771-3 ↗
24. Liu, X.Y. (2017). Contributions to the Study of Ageing Phenomena of Wooden Substrate and Traditional Materials for Transparent Finishes—A Comparative Approach for Europe and China with Applicability in Furniture Conservation/Restoration. [Ph.D. Thesis, Transilvania University].
25. Liu, R., Zhu, H., Li, K., and Yang, Z. (2019). Comparison on the Aging of Woods Exposed to Natural Sunlight and Artificial Xenon Light. Polymers, 11.10.3390/polym11040709 ↗
26. Wood photosensitivity to different artificial light sources10.1007/s00107-022-01842-2 ↗
27. Wood discoloration patterns depending on the light source10.1186/s40494-022-00795-2 ↗
28. Photodegradation at the wood-clearcoat interface10.1007/BF00204584 ↗
29. Chemical and mechanical changes during photooxidation of an acrylic clear wood coat and its prevention using UV absorber and micronized TiO210.1016/j.polymdegradstab.2013.03.029 ↗
30. Surface degradation of CeO2 stabilized acrylic polyurethane coated thermally treated jack pine during accelerated weathering10.1016/j.apsusc.2013.03.031 ↗
31. Inorganic UV absorbers for the photostabilisation of wood-clearcoating systems: Comparison with organic UV absorbers10.1016/j.apsusc.2006.08.029 ↗
32. Surface characteristics of coated soft- and hardwoods due to UV-B ageing10.1016/j.apsusc.2010.05.097 ↗
33. Enhancement of bamboo surface photostability by application of clear coatings containing a combination of organic/inorganic UV absorbers10.1016/j.porgcoat.2018.05.023 ↗
34. Novel UV-Cured Nanocomposite Used for the Protection of Walnut Wood Artworks
35. Characterizing the conservation effect of clear coatings on photodegradation of wood10.1016/j.biortech.2007.02.027 ↗
36. Protective behaviour monitoring on wood photo-degradation by spectroscopic techniques coupled with chemometrics10.1016/j.saa.2016.05.050 ↗
37. Functionalising wood by nanosol application10.1039/b718903f ↗
38. Wu, X., Yang, F., Gan, J., Kong, Z., and Wu, Y. (2021). A Superhydrophobic, Antibacterial, and Durable Surface of Poplar Wood. Nanomaterials, 11.10.3390/nano11081885 ↗
39. Panek, M., Oberhofnerova, E., Hysek, S., Sedivka, P., and Zeidler, A. (2018). Colour Stabilization of Oak, Spruce, Larch and Douglas Fir Heartwood Treated with Mixtures of Nanoparticle Dispersions and UV-Stabilizers after Exposure to UV and VIS-Radiation. Materials, 11.10.3390/ma11091653 ↗
40. Reactive UV-absorber and epoxy functionalized soybean oil for enhanced UV-protection of clear coated wood10.1016/j.polymdegradstab.2014.09.017 ↗
41. Bielerman, J. (1998). Lackadditive, Wiley-VCH. Available online: https://epdf.tips/lackadditive-german-edition.html.10.1002/9783527624768 ↗
42. FTIR and color change of the modified wood as a result of artificial light irradiation10.1016/j.jphotobiol.2010.03.010 ↗
43. Maleic Anhydride Treated Wood: Effects of Drying Timeand Esterification Temperature on Properties
44. In-Situ Chemosynthesis of ZnO Nanoparticles to Endow Wood with Antibacterial and UV-Resistance Properties10.1016/j.jmst.2016.03.018 ↗
45. A UV-shielding and hydrophobic graphitic carbon nitride nanosheets/cellulose nanofibril (gCNNS/CNF) transparent coating on wood surface for weathering resistance10.1016/j.porgcoat.2021.106440 ↗
46. An experimental method to evaluate the contribution of the wood substrate and of the coating film in the global light in-duced colour changes of wood surfaces in indoors conditions
47. Photo-degradation of water borne acrylic coated modified and non-modified wood during artificial light exposure10.15376/biores.3.2.346-362 ↗
48. Liu, X.Y., Timar, M.C., Varodi, A., Nedelcu, R., and Torcătoru, M.-J. (2022). Colour and Surface Chemistry Changes of Wood Surfaces Coated with Two Types of Waxes after Seven Years Exposure to Natural Light in Indoor Conditions. Coatings, 12.10.3390/coatings12111689 ↗
49. (2023, October 13). Available online: https://www.renneritalia.com/en/.
50. (2023, October 18). Available online: http://www.kroncolor.ro/contact.html.
51. (2023, October 27). Available online: https://www.avantes.com/.
52. (2017). Plastics—Determination of Changes in Colour and Variations in Properties after Exposure to Glass-Filtered Solar Radiation, Natural Weathering or Laboratory Radiation Sources-Requirements. Standard No. ISO-4582-2017.
53. Timar, M.C., and Beldean, E.C. (2022). Modification of Shellac with Clove (Eugenia caryophyllata) and Thyme (Satureja hortensis) Essential Oils: Compatibility Issues and Effect on the UV Light Resistance of Wood Coated Surfaces. Coatings, 12.10.3390/coatings12101591 ↗
54. (2013). Paints and Varnishes—Methods of Exposure to Laboratory Light Sources Part 3: Fluorescent UV Lamps. Standard No. ISO 16474-3:2013.
55. Photodegradation of wood at elevated temperature: Colour change10.1016/j.jphotobiol.2011.12.008 ↗
56. The role of glass as a barrier against the transmission of ultraviolet radiation: An experimental study10.1111/j.1600-0781.2009.00434.x ↗
57. Serrano, M.A., and Moreno, J.C. (2020). Spectral transmission of solar radiation by plastic and glass materials. J. Photochem. Photobiol. B, 208.10.1016/j.jphotobiol.2020.111894 ↗
58. Enhancing exterior performance of clear coatings through photostabilization of wood. Part 2: Coating and weathering performance10.1007/s11998-008-9090-z ↗
59. Kúdela, J., Sikora, A., and Gondáš, L. (2023). Wood Surface Finishing with Transparent Lacquers Intended for Indoor Use, and the Colour Resistance of These Surfaces during Accelerated Aging. Polymers, 15.10.3390/polym15030747 ↗
60. Meijer, D.M. (2005, January 26–27). A Review of Interfacial Aspects in Wood Coatings: Wetting, Surface Energy, Substrate Penetration and Adhesion; 2005. Proceedings of the COST E18 FInal Seminar, Paris, France. Available online: https://www.researchgate.net/publication/260601859_A_review_of_interfacial_aspects_in_wood_coatings_wetting_surface_energy_substrate_penetration_and_adhesion.
61. Comparative study on penetration characteristics of modern wood coatings10.1007/BF00702791 ↗
62. Quantitative measurements of capillary coating penetration in relation to wood and coating properties10.1007/s001070050469 ↗
63. Weathering properties of wood species treated with different coating applications
64. Elucidation of the degradative behavior of coated-wood surfaces exposed to artificial weathering using Raman microspectroscopy10.1016/j.porgcoat.2023.108184 ↗