含液化柳杉水性聚胺基甲酸酯/環氧樹脂/矽氧有機-無機混成材料之製備及性質

Abstract

本研究將柳杉（Cryptomeria japonica Don.；Japanese cedar）木材以聚乙二醇/丙三醇混合液為溶劑、硫酸為催化劑進行液化處理得液化木材（Liquefied wood；LW）。聚四甲基醚二醇（Polytetramethylene ether glycol；PTMG）及OH基莫耳比1/1之PTMG/LW分別與異弗爾酮二異氰酸酯（Isophorone diisocyanate；IPDI）透過預聚合法製備兩種系列水性聚胺基甲酸酯樹脂（Polyurethane resin；PU），分別為WPU（Waterborne PU）及LWPU（LW-contained waterborne PU）系列，探討鏈延長劑乙二胺（Ethylenediamine；EDA）添加量對所合成水性PU樹脂性質之影響。隨後將水性PU樹脂與水性環氧樹脂（Waterborne epoxy resin；Waterborne ER）以不同重量比混合，探討水性ER樹脂添加比例對PU/ER摻合樹脂性質之影響。另在水性PU樹脂合成過程導入3-（三乙氧矽基）丙胺（3-Aminopropyltriethoxysilane；APTES）進行改質處理使形成含有矽氧烷末端之APU樹脂，並在PU/ER及APU/ER摻合樹脂中加入四乙基矽氧烷（Tetraethoxysilane；TEOS），探討無機矽氧高分子含量對PU/ER/矽氧混成樹脂薄膜性質之影響。由試驗結果得知，LWPU樹脂液之粒徑大於WPU，而隨鏈延長劑添加比例增加，所合成水性PU樹脂之分子量降低。WPU及LWPU兩種系列水性PU樹脂比較，WPU樹脂薄膜浸水膨潤係數較小，重量保留率較高，拉伸強度、破壞伸長率及破壞能量較大。而隨鏈延長劑添加比例增加，樹脂薄膜之膨潤係數增大，重量保留率降低，拉伸強度及破壞伸長率減小。DMA分析顯示添加LW可提高PU樹脂中軟鏈段之剛性，提高鏈延長劑添加比例可降低結晶區的熱活動性。TGA分析顯示，分子鏈長度對PU樹脂熱安定性之影響效應大於分子結構。PU/ER摻合樹脂隨ER樹脂比例提高，摻合樹脂薄膜浸水時之膨潤係數下降，重量保留率提高，其中WPU/ER樹脂薄膜之拉伸強度及破壞伸長率下降，而LWPU/ER樹脂之拉伸強度及模數則提高。DSC及DMA分析顯示，ER樹脂所形成的網狀結構會限制PU分子鏈之熱活動。TGA分析顯示，PU/ER互穿網狀高分子結構可提高PU樹脂的熱抵抗性。TEOS可在PU/ER摻合樹脂中發生水解-縮合反應形成PU/ER/矽氧有機-無機混成樹脂薄膜，其中APU/ER樹脂可與TEOS反應而形成共聚合之矽氧結構。此共聚合矽氧結構可改善APU/ER混成樹脂薄膜之耐水性、耐溶劑、機械性質及熱抵抗性，且隨矽氧比例增加，對性質改善效果提高。

In this study, wood of Cryptomeria japonica was liquefied in polyethylene glycol/glycerol mixture with sulfuric acid as a catalyst to obtain liquefied wood (LW). Two series of waterborne polyurethane resin (PU), named WPU and LWPU, were prepared by reacting polytetramethylene ether glycol (PTMG) and a mixture of PTMG/LW (1/1 by OH group molar ratio) with isophorone diisocyanate (IPDI), respectively, via a prepolymerization method. The effect of the addition rate of the chain extender of ethylenediamine (EDA) on the properties of waterborne PU resin was investigated. Then waterborne PUs were mixed with the waterborne epoxy resin (ER) with different weight ratios and the influence of the amount of WER on the properties of PU/ER blended resin was investigated. In addition, an APU resin that contains a siloxane-terminated structure was prepared by introducing 3-aminopropyl- triethoxysilane (APTES) into the WPU during the synthesis. Tetraethoxysilane (TEOS) was added to PU/ER and APU/ER blended resins to investigate the effect of the content of inorganic silica on the properties of PU/ER/silica hybrid resin film. The experimental results showed that the average particle size of LWPU suspensions is larger than that of WPU suspensions. Increasing the chain extender contents, the average molecular weight of waterborne PU resin decreased. Compared with the two types of waterborne PU resin, WPU films have a smaller swelling coefficient and higher weight retention after water immersion, higher tensile strength and elongation at breaking, and greater destruction energy. With the chain extender contents increased, the swelling coefficient increased, the weight retention rate decreased, and the tensile strength and fracture elongation decreased. DMA analysis shows that the addition of LW can increase the rigidity of the soft segment in the PU resin. Increasing the chain extender contents can reduce the thermal activity of the crystalline region. TGA analysis indicates that the effect of molecular chain length on the thermal stability of PU resin is greater than that of molecular structure. Increasing the weight ratio of ER in PU/ER blended resin, the swelling coefficient of the resin film decreased and the weight retention increased after water immersion. However, the tensile strength and the elongation at breaking decreased for WPU/ER resin films but the tensile strength and modulus increased for LWPU/ER. DSC and DMA analysis showed that the thermal activity of the molecular chain of PU was restricted by the network structure of the ER resin. TGA analysis showed that the PU/ER interpenetrating network polymer structure could improve the thermal resistance of PU resin. TEOS could undergo the hydrolysis-condensation reactions in PU/ER blended resins to form PU/ER/silica organic-inorganic hybrid resin films. APU/ER blended resins could react with TEOS to form a copolymerized silica structures. The water resistance, solvent resistance, mechanical properties, and thermal resistance of APU/ER hybrid resin films could be improved by the co-polymerized silica structure. As the ratio of silica content increased, the effect of improving the properties was enhanced.