頁籤選單縮合
題 名 | 聚胺基甲酸酯透明塗裝木材光變色之解析=Illustration of Photo-Discoloration of Wood Coated with Clear Polyurethane |
---|---|
作 者 | 張上鎮; 葉汀峰; | 書刊名 | 中華林學季刊 |
卷 期 | 30:3=118 1997.09[民86.09] |
頁 次 | 頁291-300 |
分類號 | 436.188 |
關鍵詞 | 聚胺基甲酸酯透明塗料; 游離塗膜; 光劣化; 變色; 化學結構變化; 紅外線光譜分析; Polyurethane clear coating; Free film; Photodegradation; Discoloration; Chemical structure changes; Infrared spectroscopy; |
語 文 | 中文(Chinese) |
中文摘要 | 為瞭解聚胺基甲酸酯透明塗裝木材在光變色過程中,塗膜與木材所分別扮演的角色,本試驗以聚胺基甲酸酯的游離塗膜覆蓋於木片上,模擬聚胺基甲酸酯塗裝之木材。試材經人工加速耐光試驗後,分別以紫外光╱可見光光譜儀配合積分球及傅立葉紅外線光譜儀評估塗膜與木片的變色及化學結構變化,並與塗裝木片系統做一探討比較。試驗結果顯示,以游離塗膜覆蓋於木片表面之組合可以說明塗裝木片的光劣化,並可以了解透明塗裝木材的變色機構。以芳香族聚胺基甲酸脂塗裝木材之光變色,在照光初期係由塗膜及木材兩者的變色所共同造成,但隨著照光時間的增加,其顏色變化則主要是由塗膜變色所造成。進一步分析化學結構變化得知,塗膜的胺基甲酸酯鍵明顯遭受破壞,且塗膜下木材的化學結構亦受光影響而產生變化,但變化程度較直接照光的為較微。至於以脂肪族聚胺基甲酸酯塗裝之木材,由於塗膜具有較佳的光安定性,在照光過程中幾乎不變色,但是塗膜下木材之變色卻隨著照光時間增加而加劇,且經由紅外線光譜分析得知,在脂肪族PU塗膜下木材化學結構受光影響產生之變化較於芳香族 PU 塗膜下木材的為顯著,即木材成份如木質素等遭受嚴重破壞,由此可知脂肪族聚胺基甲酸酯塗裝材顏色變化主要是由木材的化學結構受光影響劣化所造成。文中亦討論抑制聚胺基甲酸酯透明塗裝木材光變色之可行方法。 |
英文摘要 | This study was to elucidate the roles of film and wood during the photodiscoloration of clear polyurethane (PU) coated wood, experimental designation using wood covered by PU free film was employed to simulate real PU coated wood. After exposure to accelerated lightfastness test, the color and chemical structure changes of the specimens were examined by UV/Visible spectrophotometer coordinated with integral sphere apparatus and Fourier Transform Infrared Spectroscope (FTIR). Results obtained from the comparison of color variations showed that the model of wood covered by free film employed could simulate clear coated wood and the mechanism of clear coated wood during discoloration could be easily illustrated. The color change of aromatic PU coated wood was caused both by film and by wood underneath during the early periods of photodegradation, but as time proceeded the discoloration of coated wood was mainly due to the color change of film itself. As for the chemical structure analysis, the urethane linkage of PU film was obviously destroyed. In addition, the chemical structures of wood beneath film were also changed during irradiation, but the change was less than that of irradiated wood directly. Because of good light stability of aliphatic PU film (PUA), it didn't appear any color change during irradiation, but the wood beneath PUA film was significantly altered. Wood components such as lignin beneath the PUA film degraded to a greater extent than that beneath the PU film during irradiation. Results showed that the discoloration of PUA coated wood was mainly due to degradation and color change of wood itself. Accordingly, some effective methods to retard the discoloration of PU and PUA coated wood during irradiation were proposed. |
本系統中英文摘要資訊取自各篇刊載內容。