- 學位論文
柳杉與相思樹木焦油處理材之耐久性
Durability of Wood Treated with Cryptomeria japonica and Acacia confusa Wood Tars
摘要
本研究目的在於以柳杉(Cryptomeria japonica)與相思樹(Acacia confusa)經炭化熱裂解製得之木焦油，探討其作為木材防腐藥劑之可行性，以增加國產造林木之應用價值。試驗係以1、2、4及6%濃度柳杉與相思樹木焦油處理放射松(Pinus radiata)與槭木(Acer spp.)試材，並進行處理材之耐淋溶性、木塊耐腐朽性、抗白蟻性及耐候性等評估。結果顯示，柳杉與相思樹木焦油處理材之藥劑留存率及藥劑流失率皆隨著木焦油處理濃度增加而增加，其中以柳杉木焦油處理材之藥劑留存率較相思樹木焦油處理材為高。而木塊耐腐朽試驗結果顯示，經淋溶後之2%柳杉木焦油及相思樹木焦油放射松處理材，其對於褐腐菌G. trabeum及L. sulphureus之耐腐朽性甚佳，且其質量損失率皆顯著低於對照組；而經淋溶後之1%柳杉木焦油與相思樹木焦油槭木處理材其對於白腐菌T. versicolor之耐腐朽性較佳，且其質量損失率亦較對照組低。而抗白蟻試驗結果顯示，臺灣家白蟻飼養於經淋溶後之1%柳杉與相思樹木焦油處理材4週後，其處理材質量損失率皆顯著低於對照組，且以槭木處理材之抗蟻性較放射松處理材佳。耐候性試驗結果顯示，放射松經1、2、4及6%柳杉木焦油與相思樹木焦油處理後，其處理材表面顏色隨著處理濃度增加其變化則越大，而L*值及接觸角則會逐漸降低，a*與b*值之顏色變化逐漸偏綠與偏藍。而經UVA-340與UVB-313燈管照光32天後，其相思樹木焦油處理材色差值(ΔE*)之變化較柳杉木焦油處理材大，但兩者木焦油處理材ΔE*之變化皆較對照組小，而接觸角之變化則隨著照光時間增加而減小，且兩種木焦油處理材皆以經UVB-313燈管照光後之表面濕潤性變化較UVA-340燈管照光者大。綜合上述結果顯示，以柳杉木焦油與相思樹木焦油處理放射松及槭木試材，皆具優異之耐腐朽性及抗白蟻性，且其處理材經紫外光照射後，可增加兩者處理材之濕潤性性，有利後續保養作業之塗裝，因此柳杉與相思樹木焦油極具作為木材防腐劑之潛力。
並列摘要
Increasing the value and efficacy of utilization for the tree species in Taiwan forest is one of the important issues in the development of sustainable forest management. Therefore, the goal of this study was to investigate the potential of wood tars, obtained from Cryptomeria japonica and Acacia confusa, as wood preservatives in order to increase their utilization and value. Pinus radiata and Acer spp. woods treated with four concentrations (1, 2, 4, and 6%) of C. japonica and A. confusa wood tars were evaluated for leachability, fungal decay resistance, termite resistance, and weathering durability. The leaching test results showed that the chemical retention of wood treated with C. japonica and A. confusa wood tars increased as the concentration increased. Moreover, the chemical retention of wood treated with C. japonica wood tar was higher than those treated with A. confusa wood tar. Results of the fungal decay resistance test of wood (Pinus radiata) treated with 2% C. japonica and A. confusa wood tars after leachability test, exhibited higher decay resistance against brown-rot fungi (G. trabeum and L. sulphureus) than the control. Similarly, lower mass loss was observed on wood (Acer spp.) treated with 1% C. japonica and A. confusa wood tars after leachability test and exposure to white-rot fungus (T. versicolor). According to the termite resistance test, the mass loss of wood treated with 1% C. japonica and A. confusa wood tars after leachability test and exposure to C. formosanus Shiraki was lower than that of the control. In addition, wood of Acer spp. revealed better termite resistance than Pinus radiata. The surface color of treated woods was significantly changed as the concentration of wood tar increased. Moreover, the changes in lightness (L*) and contact angle (°) were gradually decreased, and the respective a* and b* values turned green and blue. The weathering durability test demonstrated that the change in ΔE* values of wood (Pinus radiata) treated with A. confusa wood tar was higher than those treated with C. japonica wood tar after exposure to UVA-340 and UVB-313 for 32 days. However, ΔE* values of wood treated with either wood tar was lower than the control. Furthermore, the change in contact angle (°) tended to decrease as exposure time increased, and the wettability of treated wood exposed to UVB-313 was higher than those exposed to UVA-340. Based on the results of this study, wood (Pinus radiata and Acer spp.) treated with C. japonica and A. confusa wood tars showed excellent fungal decay resistance and termite resistance. Results also revealed that exposure to ultra violet light enhanced the wettability and coating efficiency of wood treated with both wood tars. As a result, it could be suggested that both wood tars have great potential to be developed as wood preservatives in the furture.