水性環氧樹脂乳化劑之設計、合成與應用

Abstract

本研究藉由利用一級胺以及二級胺上之活性氫對環氧基良好的反應性，設計將雙酚A型的環氧樹脂鏈段導入聚醚胺 (Jeffamine)，成功地以一種簡便的方式合成具有親水與親油性基團的水性環氧樹脂型乳化劑，並以相翻轉的方法將環氧樹脂型乳化劑成功乳化分子量為6100 g/mol和12000 g/mol的環氧樹脂，並探討不同鏈長的環氧樹脂型乳化劑在乳化性能以及乳液熱性質及穩定性上的影響。 在乳化劑的製備實驗中發現低分子量的環氧樹脂(MW=1000，1250，1520，1630 g/mol)可與聚醚胺(M2070)反應形成有效的乳化劑，並且環氧樹脂與聚醚胺的摩爾比為1:2具有最佳的乳化效果。將合成的水性環氧樹脂乳化劑水性化環氧樹脂後可得到粒徑為500-1000 nm 的乳液，並觀察到當乳化劑結構中的環氧樹脂分子量越小，其乳化得到的乳液會有越小的粒徑值，乳液安定性越高；從差式掃描量熱儀 (DSC)的測量結果中顯示，水性環氧樹脂乳液成膜後的玻璃轉移溫度(Tg)介於62-72 °C，並且其Tg值隨著乳化劑中環氧樹脂分子量的上升而提升，其中環氧樹脂分子量為1630 g/mol的乳化劑可得到最高的Tg值為71.5℃，具有最佳的熱穩定性。由實驗結果可得到，乳化劑中環氧樹脂分子量的大小對乳液的粒徑值與成膜後的Tg值有相反的影響。此外，將水性化的環氧樹脂乳液塗覆於金屬表面，其黏著力可達16.7 N/mm以及在5小時鹽霧測試中金屬表面腐蝕程度皆在40%以下，具有優秀的黏著力與抗腐蝕性表現。本實驗將乳化劑進行分子結構設計並以相翻轉法成功水性化擴鏈後的環氧樹脂，再分別對乳化劑、高分子量的環氧樹脂以及水性環氧樹脂乳液作化學結構鑑定、熱性質檢測、乳液粒徑值分析以及穩定性測試等分析，期望可應用於非離子型水性環氧樹脂乳液之開發。

In this study, a new class of epoxy-Jeffamine emulsifiers for preparing waterborne epoxy resins were successfully synthesized. Bisphenol A-based epoxy resins were covalently linked with hydrophilic Jeffamines to form the nonionic surfactants with hydrophilic and hydrophobic moieties through the ring opening reaction of the epoxide groups with the amine groups. The surfactants of the molar ratio of epoxy/Jeffamines (M2070) = 0.5 and the epoxies with low molecular weight (MW = 1000, 1250, 1520, 1630 g/mol) are effective for emulsifying the epoxy resins with the molecular weight of 6100 g/mol in water through the phase inversion method. We have also synthesized the epoxy resins with higher molecular weights by using ethanolamine to extend the epoxy chains. The epoxy resin with MW = 12000 g/mol can also be successfully emulsified in water by the new synthesized surfactants. The dynamic light scattering (DLS) measurements show that the particle sizes of the emulsions are in the range between 500 and 1000 nm, and the particles size decreases with decreasing the molecular weight of the epoxy in the surfactants. The differential scanning calorimetry (DSC) measurements reveal that the glass transition temperatures (Tg) of the solidified epoxies cast from the emulsions is in the range between 62 and 72 °C, and the Tg is increased with increasing the molecular weight of the epoxy in the surfactants. Due to the good stability of the emulsions and the good thermal properties of the epoxies, after coating the emulsions on the metal surfaces, the films are smooth and exhibit excellent corrosion resistance and high adhesive force (16.7 N/mm). The newly developed emulsifiers are highly potential in preparing waterborne epoxy emulsions that aiming to the applications of adhesives that require strong adhesion as well as high stability.