二階段聚合法製備之PU樹脂性質－NCO／OH莫耳比之影響

Properties of PU Resin Prepared with a Two-stage Polymerization: The Influence of NCO/OH Molar Ratio

梁宸鈞(Chen-Jyun Liang) ； 劉旭晟(Hsu-Chen Liu) ； 李文昭(Wen-Jau Lee)

《林產工業》 37卷4期 (2018/12) Pp. 181-192

https://doi.org/10.6561/FPI.201812_37(4).0001

摘要

本研究以聚四甲基醚二醇（Polytetramethylene ether glycol；PTMG）為多元醇原料，異氟爾酮二異氰酸酯（Isophorone diisocyanate；IPDI）為異氰酸酯原料，乙二胺（Ethylenediamine；EDA）為鏈延長劑製備聚胺基甲酸酯樹脂（Polyurethane resins；PU）。PU樹脂合成時採用二階段聚合法，第一階段先將IPDI與PTMG在NCO／OH莫耳比1.5／1、1.75／1及2.0／1條件下反應形成PU預聚合物，再添加EDA進行第二階段鏈延長反應形成高分子化PU樹脂，探討預聚合階段採用NCO／OH莫耳比對所製備PU樹脂性質之影響。DSC分析顯示IPDI與PTMG須藉由加熱或添加催化劑促進其架橋反應。隨預聚合階段所採用NCO／OH莫耳比提高，反應的放熱量減少，所製備PU樹脂的黏度及平均分子量降低。FTIR分析顯示所製備PU樹脂同時具備胺酯、尿素及醯胺結構，且隨NCO／OH莫耳比提高，尿素及醯胺結構之比例增加。PU薄膜具備軟韌性質，其拉伸變形量可達34倍以上。預聚合階段採用莫耳比2.0／1之PU薄膜有較佳的耐水性及耐溶劑性。DMA結果顯示所製備PU樹脂屬於半結晶性高分子材料，其內部存在兩相結構。TGA分析顯示PU樹脂由於熱裂解所造成的重量損失可區分為三個階段，隨NCO／OH莫耳比提高，第一階段歸因於硬鏈段熱裂解的重量損失增加，但第二階段由於軟鏈段熱裂解的重量損失則減少。

關鍵字

NCO／OH莫耳比 ； 聚胺基甲酸酯 ； 樹脂薄膜 ； 熱性質 ； 二階段聚合

並列摘要

In this study, polyurethane resins (PU) were prepared with polytetramethylene ether glycol (PTMG) as a polyol, isophorone diisocyanate (IPDI) as an isocyanate, and ethylenediamine (EDA) as a chain extender. The PU resins were synthesized by a two-stage polymerization. In the first stage, PU prepolymers were formed by reacting IPDI with PTMG at the NCO/OH molar ratio of 1.5/1, 1.75/1 and 2.0/1, and then EDA was added for the second stage of chain extension reaction to form PU polymer resins. The effect of the molar ratio of NCO/OH used in the prepolymerization on the properties of PU resins was investigated. DSC analysis showed that the crosslinking reaction between IPDI and PTMG must be promoted by heating or adding a catalyst. As the NCO/OH molar ratio used in the prepolymerization increased, the exothermic heat of the reaction reduced, and the viscosity and average molecular weight of the prepared PU resin lowered. FTIR analysis showed that the prepared PU resin had both urethane, urea and amide structure, and the ratio of urea and amide raised with the NCO/OH molar ratio increased. The PU film had a soft and tough property, and its tensile strain could reach more than 3400%. The PU film with molar ratio of 2.0/1 during the prepolymerization had better water resistance and solvent resistance. The results of DMA showed that the prepared PU resins were a semi-crystalline polymer material, and a two-phase structure was present inside. TGA analysis showed that the weight loss of PU resin due to the thermal degradation could be divided into three stages. As the NCO/OH molar ratio increased, the weight loss at the first stage that attributed to the thermal degradation of hard segments increased, but the weight loss of the second stage that attributed to the soft segments decreased.

並列關鍵字

NCO/OH molar ratio ； Polyurethane ； Resin film ； Thermal properties ； Two-stage polymerization