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題 名 | 塗裝木材人工加速劣化與自然曝露試驗之相關性(3)戶外耐候性=Correlation of Accelerated Testing to Natural Exposure of Coated Wood (Ⅲ) Outdoor Weathering |
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作 者 | 張上鎮; 蕭雅方; | 書刊名 | 國立臺灣大學農學院實驗林研究報告 |
卷 期 | 12:2=220 1998.06[民87.06] |
頁 次 | 頁69-86 |
分類號 | 436.188 |
關鍵詞 | 杉木; 硬槭木; 聚胺基甲酸酯塗料; 變色; 色差值; 化學結構; 戶外耐候試驗; 人工加速劣化試驗; 相關性; China fir; Hard maple; Polyurethane coating; Discoloration; Color difference; Chemical structure; Outdoor weathering; Accelerated testing; Correlation; |
語 文 | 中文(Chinese) |
中文摘要 | 本試驗係將杉木與硬槭木之素材及聚胺基甲酸酯(PU)塗裝材經過戶外耐候試驗 、UVA-340 加速耐候試驗與 UVA-340 加速耐光試驗後, 分析其表面顏色、光澤度與塗膜之 化學結構等性質變化;此外,亦將試驗所得結果進行迴歸與相關性分析,並計算加速因子( AF )及利用曲線擬合法推算加速平移因子( ASF )。 試驗結果顯示,除了戶外耐候試驗 之杉木及硬槭木素材之外,其他試材經過曝露試驗後的顏色變化趨勢類似,其色差值、黃色 指數、a ��值與 b ��值皆隨試驗時間之增長而增加,而明度保留率與 L ��值則隨試驗時間 之增長而減少,且顏色變化都是趨向紅黃色系。利用 Spearman 等級相關求算試材經過二種 加速劣化試驗與戶外耐候試驗後顏色變化的相關性, 得知 UVA-340 加速耐候試驗較 UVA- 340 加速耐光試驗為佳。 又利用色差值所求得的 AF 值都大於 ASF 值, 表示利用 AF 和 ASF 做為推估試材於實際曝露試驗色差值變化的程度有所差異,且 AF 及 ASF 值會受試 材種類及試驗方法的影響而改變,其中, 以 PU 塗裝杉木試材的 AF 值及 ASF 值為最小。 PU 塗膜經過 UVA-340 人工加速耐候試驗後,由其紅外線光譜各特性吸收峰之相對強度變化 所求算之 AF 值加以比較,顯示除了苯環與胺基甲酸酯劣化產生含有羰基及羧酸基劣化衍生 物之外,可能還有其它 PU 塗膜的組成分也產生劣化,生成含有羰基及羧酸基劣化衍生物。 此外, 以 PU 塗膜化學變化求算之 AF 值較以 PU 塗裝材色差值變化求算的為小,顯示 PU 塗裝材在耐候試驗中,光線與水分除了對表面的塗膜產生劣化外,亦會對底層的木材產生影 響而造成劣化。 |
英文摘要 | Variation in the color difference, gloss, and chemical structures of uncoated and polyurethane coated China fir and hard maple, resulting from outdoor weathering, exposure to an accelerated lightfastness tester equipped with UVA-340 sunlamps, and exposure to the accelerated weathering tester, were examined. In addition to the regression and correlation analyses employed in this study, the acceleration factor (AF) was calculated. The accelerated shift factor (ASF) for the entire period of exposure testing of coated wood was determined by the curve fitting method. Except for the uncoated specimens exposed to the outdoors, the brightness retention and L��value decreased, whereas the color difference, yellowness index, a��value, and b��value increased as a function of exposure time. The color on the coated specimen surface changed to reddish yellow after outdoor weathering and exposure to the accelerated durability tester. In comparing the color differences of specimens obtained from the three different exposure tests, the results obtained from the accelerated weathering test (8 hr. UV/4 hr.cond.) showed a reasonable Spearman rank correlation with those from the outdoor weathering. In terms of color difference , the Af values were larger than the ASF values. Thus, different results were obtained when the accelerated durability tests were used to estimate the color difference of a specimen to be exposed to the outdoors. The AF and ASF values changed using different testing methods and specimens. The AF and ASF values obtained for polyurethane coated China fir were the smallest. Comparisons of the AF values obtained from the relative intensities of the characteristic absorption peaks in the IR spectra of polyurethane, revealed that the carbonyl- and carboxylic-degradation products were derived not only from the destruction of aromatic ring and urethane linkage, but also from the deterioration of the other chain structures. Because the AF values for chemical structure change of the coating were smaller than those for color difference in PU coated wood, weathering tests (using light and water) revealed that degradation induced by light and water occurred on the surface of coating films and at the interface between the wood and the coatings. |
本系統中英文摘要資訊取自各篇刊載內容。