Violet light causes photodegradation of wood beyond the zone affected by ultraviolet radiation
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Yutaka Kataoka
Abstract
The limited penetration of wood by light explains why the weathering of wood exposed outdoors is a surface phenomenon. Wood is rapidly degraded by short-wavelength UV radiation, but the penetration of light into wood is positively correlated with its wavelength. Hence, sub-surface degradation is likely to be caused by longer-wavelength light that still has sufficient energy to degrade wood. In this paper we test this hypothesis and determine the wavelengths of visible light that extend photodegradation into wood beyond the zone affected by UV radiation. Sugi (Cryptomeria japonica) earlywood was exposed to UV and visible light with narrow band gaps (20 nm) and the penetration of light into the wood was measured using a photodetector. Photodegradation was depth-profiled using FT-IR microscopy. There was a positive correlation between the penetration of light into sugi earlywood and the wavelength of the incident radiation within the range 246–496 nm. The depth of photodegradation also increased with wavelength up to and including the violet region (403 nm) of the visible spectrum. Blue light (434–496 nm) penetrated wood to a greater extent than violet light and was capable of bleaching the wood, but it did not significantly modify lignin, and hence it was not responsible for sub-surface photodegradation of wood. We conclude that violet light is the component of the visible spectrum that extends photodegradation into wood beyond the zone affected by UV radiation. Accordingly, surface treatments designed to protect wood used outdoors should shield wood from the effects of violet light.
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Articles in the same Issue
- MWL fraction with a high concentration of lignin-carbohydrate linkages: Isolation and 2D NMR spectroscopic analysis
- Papermaking properties of the ECF-bleached kraft pulps from first-thinning Scots pine (Pinus sylvestris L.)
- Syntheses and properties of liquefied products of ozone treated wood/epoxy resins having high wood contents
- Quality control of thermally modified timber: Interrelationship between heat treatment intensities and CIE L*a*b* color data on homogenized wood samples
- Violet light causes photodegradation of wood beyond the zone affected by ultraviolet radiation
- Dynamic mechanical analysis of dry wood: Linear viscoelastic response region and effects of minor moisture changes
- Material properties and their interrelation in chemically modified clear wood of Scots pine
- Effect of treatments with 1,3-dimethylol-4,5-dihydroxy-ethyleneurea (DMDHEU) on the tensile properties of wood
- Penetration of amino-silicone micro- and macro-emulsions into Scots pine sapwood and the effect on water-related properties
- Search for a relationship between stress wave velocity and internal stresses in eucalypts and radiata pine
- Kiln-drying lumber quality of hybrid poplar clones
- Heat and mass transfer in wood composite panels during hot pressing: Part 3. Predicted variations and interactions of the pressing variables
- Heat and mass transfer in wood composite panels during hot pressing: Part 4. Experimental investigation and model validation
- Dielectric relaxation of water adsorbed on wood and charcoal
- Properties of piezoelectric voltage considering the microscopic structure of wood cell walls
- Adjusting for fibre length-biased sampling probability using increment cores from standing trees
- External and internal fungal flora of pine sapwood (Pinus sylvestris L.) specimens in above-ground field tests at six different sites in south-west Germany
- Award Presentation on the occasion of the European Workshop on Lignocellulosics and Pulp (EWLP 2006) in Vienna
- Phenolic compounds in silver birch (Betula pendula Roth) wood
Articles in the same Issue
- MWL fraction with a high concentration of lignin-carbohydrate linkages: Isolation and 2D NMR spectroscopic analysis
- Papermaking properties of the ECF-bleached kraft pulps from first-thinning Scots pine (Pinus sylvestris L.)
- Syntheses and properties of liquefied products of ozone treated wood/epoxy resins having high wood contents
- Quality control of thermally modified timber: Interrelationship between heat treatment intensities and CIE L*a*b* color data on homogenized wood samples
- Violet light causes photodegradation of wood beyond the zone affected by ultraviolet radiation
- Dynamic mechanical analysis of dry wood: Linear viscoelastic response region and effects of minor moisture changes
- Material properties and their interrelation in chemically modified clear wood of Scots pine
- Effect of treatments with 1,3-dimethylol-4,5-dihydroxy-ethyleneurea (DMDHEU) on the tensile properties of wood
- Penetration of amino-silicone micro- and macro-emulsions into Scots pine sapwood and the effect on water-related properties
- Search for a relationship between stress wave velocity and internal stresses in eucalypts and radiata pine
- Kiln-drying lumber quality of hybrid poplar clones
- Heat and mass transfer in wood composite panels during hot pressing: Part 3. Predicted variations and interactions of the pressing variables
- Heat and mass transfer in wood composite panels during hot pressing: Part 4. Experimental investigation and model validation
- Dielectric relaxation of water adsorbed on wood and charcoal
- Properties of piezoelectric voltage considering the microscopic structure of wood cell walls
- Adjusting for fibre length-biased sampling probability using increment cores from standing trees
- External and internal fungal flora of pine sapwood (Pinus sylvestris L.) specimens in above-ground field tests at six different sites in south-west Germany
- Award Presentation on the occasion of the European Workshop on Lignocellulosics and Pulp (EWLP 2006) in Vienna
- Phenolic compounds in silver birch (Betula pendula Roth) wood
