添加幾丁聚醣對水性聚胺基甲酸酯樹脂機械性質及熱性質之影響

Influence of the addition of chitosan on the mechanical and thermal properties of waterborne polyurethane resin

水性聚胺基甲酸酯樹脂（Waterborne polyurethane resin; WPU）乃利用水為分散相的一液型PU樹脂，為一種環境友善的合成樹脂。幾丁聚醣（Chitosan）為幾丁質（Chitin）經脫乙醯處理所得之聚葡萄糖胺（Polyglucosamine），為自然界最豐富的天然含胺基多醣類。本研究以聚四甲基醚二醇（Polytetramethylene ether glycol）為多元醇原料，二羥甲基丙酸（Dimethylolpropionic acid）為內部乳化劑，在NCO/OH官能基莫耳數比1.6/1.0條件與異弗爾酮二異氰酸酯（Isophorone diisocyanate）反應形成預聚合樹脂，隨後加入三乙胺進行中和反應，加入水使形成分散液，並利用乙二胺進行鏈延長反應而得WPU樹脂，並探討在所得WPU樹脂中添加幾丁聚醣對WPU薄膜機械性質和熱性質之影響。由結果得知，隨幾丁聚醣含量增加，WPU樹脂薄膜之拉伸模數提高，熱活動性增大，但拉伸強度、破壞伸長率及吸收能量則降低。DMA分析顯示，隨幾丁聚醣含量增加，WPU樹脂薄膜低溫側阻尼值波峰降低，高溫側波峰則提高。添加幾丁聚醣並未改變WPU樹脂之熱裂解行為，但可提高在高溫時之熱抵抗性及加熱至500℃時之焦炭率。 Waterborne polyurethane resin (WPU) is an one-component PU resin that uses water as a dispersion phase. It is an environmentally friendly synthetic resin. Chitosan is a polyglucosamine obtained by deacetylation of chitin. It is the most abundant natural amino-containing polysaccharide. In this study, a prepolymer were prepared by using polytetramethylene ether glycol as the polyols and dimethylolpropionic acid as the internal emulsifiers and reacted with isophorone diisocyanate with the NCO/OH molar ratio of 1.6/1.0. Subsequently, the WPU resin was obtained by the addition of triethylamine for neutralization, water for dispersion, and ethylenediamine for chain extension reaction. The effect of adding chitosan on the mechanical and thermal properties of the WPU film was investigated. The results show that the tensile modulus and thermal activity of WPU film increased with the increase of chitosan content, but the tensile strength, elongation at break and absorption energy decreased. DMA analysis shows that with the increase of chitosan content, the value of the damping peak at the low temperature side decreased, while the value of the peak appeared at the high temperature side increased. The addition of chitosan increased the thermal resistance at high temperatures and the char content of the WPU resin at the temperature of 500℃ without affecting the thermal degradation behavior.