Please use this identifier to cite or link to this item:
Polyhydric Alcohol Liquefied Wood and Its Application in the Manufacturing of Polyurethane Foam
|關鍵字:||Polyhydric Alcohol;多元醇;Polyurethane;Liquefied Wood;Foam;聚胺基甲酸酯;液化木材;發泡體||出版社:||森林學系||摘要:||
本研究將杉木(Cunninghamia lanceolata；China fir)及相思樹(Acacia confusa；Taiwan acacia)木材於多元醇(Polyhydric alcohol)液體中以H2SO4為催化劑進行液化處理，探討樹種、聚乙二醇(Polyethylene glycol；PEG)分子量、PEG/Glycerol (丙三醇)比例、催化劑添加量及液化處理時間等對液化效果之影響，並進一步將不同液化木材與HDI (Hexamethylene diisocyanate)、PMDI (Polymeric methylene diphenylene diisocyanate)、Desmodur N (HDI trimer)、Desmodur L (Toluene diisocyanate and trimethylol propane adduct)等四種異氰酸酯反應製造聚胺基甲酸酯(Polyurethane；PU)發泡體，探討不同種類液化木材、異氰酸酯、添加劑及各成分混合比等對PU發泡體性質之影響。
由試驗結果得知，木材以PEG為溶劑進行液化處理時，樹種、PEG分子量及PEG/Glycerol比例等為影響液化效果之主要因素，其中杉木之液化效果優於相思樹，且杉木以PEG-400/Glycerol比例為90/10、H2SO4添加量為3 %有最佳之液化效果，液化處理時間75 min時幾已完全溶解。由FT-IR之結果得知木材於PEG中進行液化時，部分PEG與木材產生化學結合。
液化木材應用於PU發泡體製造時，木材之液化條件、異氰酸酯種類、兩者之調配比例(R)、發泡劑及界面活性劑添加量等均影響其所製造PU發泡體之性質。不同異氰酸酯與液化木材反應時，其發泡體形成速度為PMDI>HDI>Desmodur N>Desmodur L。液化木材採用之PEG分子量較大者，其所製造PU發泡體之發泡程度較高；液化木材中Glycerol比例較高者，則其PU發泡體性質較硬脆。四種異氰酸酯中以PMDI與液化木材所製造之PU發泡體最為優良，且加工性良好；以脂肪族異氰酸酯Desmodur N所製造之PU發泡體較為柔軟，而以HDI與Desmodur L製造之PU發泡體則發泡效果不佳。又PU發泡體製造時，以水為發泡劑者其發泡效果優於異丙醚，添加較多界面活性劑則使發泡體之氣泡較為完整且均勻，提高NCO/(OH+COOH)比例會使PU發泡體之壓縮強度、拉伸強度及耐溶劑性增大。
China fir (Cunninghamia lanceolata) and Taiwan acacia (Acacia confusa) wood were liquefied in polyhydric alcohol at the presence of H2SO4 as catalyst. The effects of wood species, molecular weight of polyethylene glycol (PEG), PEG/Glycerol ratio, catalyst content, and treatment time on liquefaction result were investigated in this study. In preparation of polyurethane(PU) foam, these liquefied woods were further reacted with four kinds of isocyanate, such as HDI (Hexamethylene diisocyanate)、PMDI (Polymeric methylene diphenylene diisocyanate)、Desmodur N (HDI trimer) and Desmodur L (Toluene diisocyanate and trimethylol propane adduct) respectively. The effects of the kinds of liquefied wood, isocyanates, additives and each component ratio on the properties of PU foam were also investigated.
From the results of the studies were observed that the factors such as wood species, molecular weight of PEG and PEG/Glycerol ratio affected the properties of liquefied wood when wood was liquefied in PEG. The performance of liquefaction of China fir was better than that of Taiwan acacia. The best liquefaction conditions of China fir were the PEG-400/Glycerol by weight of 90/10 ratios and 3 % H2SO4 content. Wood could be almost liquefied thorough within 75 min in the PEG and parts of PEG chemical combined with wood were found by FT-IR analysis.
The properties of PU foam made from liquefied wood, would be influenced by the conditions of wood liquefaction, the kinds of isocyanate, the ratio of NCO/(OH+COOH) and in addition of surfactant and blowing agent. When various isocyanate were reacted with liquefied wood, the rate of foaming were at the order of PMDI>HDI>Desmodur N>Desmodur L. The PU foam prepared from liquefied wood with higher PEG molecular weights had the higher degree of foaming and with higher Glycerol content was harder and more brittle. Among of four kinds of isocyanates, PU foam prepared from PMDI and liquefied wood had the best performance and good processing. PU foam prepared from aliphatic isocyanate such as Desmodur N was soft talent. In addition, PU foam prepared from HDI and Desmodur L had inferior of blowing results. PU foam prepared with water as blowing agent had better than that with Isopropyl ether. The bubbles of PU foam would be more completely and uniformly by addition of more surfactant. The higher compression strength, tensile strength and solvent resistance would be getted with more NCO/(OH+COOH) ratio of PU foam.
|Appears in Collections:||森林學系|
Show full item record
TAIR Related Article
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.