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題名 | 未塗裝木質材料光劣化後之表面性質變化=Surface Property Changes of Uncoated Woody Materials Induced by Light |
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作者 | 張上鎮; 張惠婷; Chang, Shang-tzen; Chang, Hui-ting; |
期刊 | 中華林學季刊 |
出版日期 | 19970300 |
卷期 | 30:1=116 1997.03[民86.03] |
頁次 | 頁45-54 |
分類號 | 474.33 |
語文 | chi |
關鍵詞 | 木質材料; 光劣化; 耐光性; 顏色; 粗糙度; 表面硬度; 化學結構; Woody material; Photodegradation; Light-fastness; Color; Roughness; Surface hardness; Chemical composition; |
中文摘要 | 木質材料可以吸收大部分紫外光區的光線,是一種優良的裝潢材料,但是長期吸收光線後會產生光劣化。本試驗之目的係比較各種裝潢材料的耐光性,及分析木質材料照光後之表面顏色、化學結構及其他物理性質變化。比較各種裝潢材料之耐光性,以PVC人造板為最差,而木質材料中,則以蔗渣板與紅櫟木的顏色變化較少。木材照光後,表面產生黃化且顏色變暗,淺色木材如杉木、美國鐵杉的光變色程度大於深色木材,顯示淺色木材的耐光性較深色木材為差。至於光劣化木材的化學結構變化,由紅外線光譜分析顯示,木質素與全纖維素的特性吸收峰強度降低,即木質素與全纖維素結構降解,產生含有乙酸酚酯、及其他酯類、羧酸基與羰基之衍生物,其中又以木質素苯環結構的破壞最為明顯,且由紫外光 -可見光光譜分析顯示,照光後木材表面產生黃色的水溶性劣解物。照光後木材表面化學結構的改變,不但使其顏色黃化,且粗糙度亦隨著照光時間增長而增大,而表面硬度則在照光初期稍為增大,然後逐漸降低,在照光後期甚會低於未照光的硬度。 |
英文摘要 | Woody materials possess the property of absorbing ultraviolet light, and they are the most suitable decorative materials. As a consequence of absorbing light, however, wood is susceptible to light-induced degradation. The objectives of this study were to compare the light-fastness of some decorative materials, and to analyze the post-photodegradation changes in surface property of wood such as color, roughness, hardness and chemical compositions. Comparisons of the color variation of the decorative materials indicated that the light-fatness of PVC panel was the worst. Discoloration of the bagasse panel and red oak specimen were less than the other woody decorative materials. The color of wood turned yellow and faded with the time of irradiation. Light-induced discoloration of the light-colored wood was more servere tha that of the dark-colored:wood, indicating light fastness of the dark-colored wood was superior to the light-colored wood. Results from infrared spectra of the UV-irradiated wood surfaces demonstrated that the absorption intensities of the characteristic functional groups of lignin and holocellulose diminished. Decrement of the aromatic ring content in lignin was significant. In addition, formation of carbonyl containing derivatives and phenolic acetate or other esters were detected on the degraded wood surfaces. According to the analysis of UV-VIS spectra of the aqueous-extracts of the degraded wood, there were yellowish water-soluble compounds generated on the wood surfaces after UV irradiatioin. Changes in chemical compositions of photodegraded wood not only resulted in yellowing of wood, but also roughened the surfaces as irradiation proceeded. Surface hardness of the wood increased slightly during the early stages of UV irradiation and decreased gradually with further irradiation. Hardness of the irradiated wood was eventually lower than that of the unirradiated wood in the later stage of UV irradiation. |
本系統之摘要資訊系依該期刊論文摘要之資訊為主。