利用可去除之觸發劑製備高效能環氧樹脂乳液: 結構設計與應用

Abstract

本研究利用胺基上之活性氫對環氧基良好的反應性將3-二乙氨基丙胺(3-(Diethylamino)propylamine, 簡稱DEAPA)與環氧樹脂進行擴鏈改質，成功地將三級胺的結構導入環氧樹脂的分子鏈中使其具有酸觸發劑的響應性，因此可藉由離子化與去離子化的過程調控其親疏水性，我們將此特性應用到製備水性環氧樹脂上，成功地製備出具有良好穩定性的環氧樹脂乳液，並藉由選用易去除的酸觸發劑，使環氧樹脂乳液能回復到疏水狀態。此外，透過高分子結構設計製備親疏水鏈段較分明的環氧樹脂，並經由實驗結果證實新設計之水性環氧樹脂可同時具有優異的熱性質與乳液穩定性。在比較用不同的酸觸發劑或市售之界面活性劑來水性化環氧樹脂的實驗結果顯示，藉由外加界面活性劑來水性化環氧樹脂雖然能夠成功地製備出乳液，但容易使乳液的玻璃轉移溫度(Tg)降低，並且乳液穩定性也不佳。而使用酸觸發劑只需少量就可以成功製備穩定環氧樹脂乳液，並且不會降低環氧樹脂本身的Tg。後續將乳液塗覆於金屬表面可具有良好地黏著性，約17~18 N/mm2 ，而乳液塗覆薄膜之抗腐蝕性則與DEAPA的含量成反比。綜上所述，本實驗成功藉由高分子結構設計製備出穩定、具有高Tg的環氧樹脂乳液。 關鍵字：水性環氧樹脂、乳液、化學改質、酸響應高分子、高分子結構設計

In this study, amine-modified epoxy-based polymers were successfully synthesized. Epoxide groups can easily undergo ring opening reaction with active hydrogens on amines. In our work, epoxy resins were modified with 3-(diethylamino)propylamine (DEAPA) to introduce tertiary amine groups to the polymer chains. With tertiary amine groups, the epoxy polymers can respond to the addition of acids to form ionic complexes. In this system, hydrophilicity can be tuned by protonation or deprotonation process. With this property, epoxy emulsions with excellent stabilities were successfully prepared. Apart from that, by the addition of acids with low boiling points, the hydrophilic state could be reversed by removing the acids afterward. In terms of polymer structure design, we prepared epoxy polymers with distinct hydrophilic and hydrophobic segments. These epoxy polymers were capable of forming stable emulsion and have excellent thermal properties. When compared with the results of different acid-triggered surfactants, the epoxy polymers could be also emulsified by the commercial surfactants. However, these emulsions were not stable enough and their thermal properties were poorer by the addition of the commercial surfactants. On the other hand, the emulsions triggered by CO2 or acetic acid only required a small amount of acids to achieve excellent emulsion properties without decreasing the thermal properties of epoxy polymers significantly. Furthermore, these epoxy emulsions were applied for metal coatings. Excellent adhesion forces of about 17~18 N/mm2 were obtained. As for corrosion resistance, the less amine content the epoxy polymer has, the better the corrosion resistance is, depending on the content of DEAPA. To sum up, this research successfully developed a series of water-dispersible amine-modified epoxy polymers with polymer structure design, which exhibited great potential as adhesives and corrosion resistance coatings. Keywords: Waterborne epoxy resins, Emulsions, Chemical modification, Acid-response polymers , Polymer structure design