College of Civil and Transportation Engineering, Guangdong Province Key Laboratory of Durability for Marine Civil Engineering, Shenzhen University, Shenzhen 518060, China; Center of Chemistry for Frontier Technologies, Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
Center of Chemistry for Frontier Technologies, Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
Int J Biol Macromol. 2024 Feb;257(Pt 2):128755. doi: 10.1016/j.ijbiomac.2023.128755. Epub 2023 Dec 12.
The practical applications of waterborne epoxy coatings are limited due to their poor barrier properties caused by the formation of numerous micropores and defects during the curing process. Herein, cellulose nanocrystals (CNCs)-reinforced waterborne epoxy coatings were fabricated by the direct addition of 0.2-1.0 wt% CNCs to waterborne epoxy emulsion followed by amine curing agent addition and spray coating. The incorporation of 0.2-0.5 wt% CNCs had no discernible impact on the stability of the waterborne epoxy emulsion. This led to the uniform dispersion of CNCs in the cured coating matrix, as evidenced by differential scanning calorimetry analysis. Because of the good compatibility, 0.2-0.5 wt% CNCs-reinforced epoxy coatings exhibited superior corrosion protection performance for steels. The impedance modulus of these coatings remained at 10 Ω cm after being immersed in a 3.5 wt% NaCl solution for 21 d. The hydroxyl groups present on the CNC surface undergo a reaction with the epoxy group, enhancing intermolecular interaction and leading to the formation of a defect-free dense structure that improves coating barrier properties. However, the incorporation of an excessive amount of CNCs (i.e., 0.8 and 1.0 wt%) significantly compromised the corrosion resistance of epoxy coatings due to aggregation-induced coating defects. Overall, this study provides a facile and green strategy for corrosion resistance improvement of waterborne epoxy coatings.
水基环氧树脂涂料的实际应用受到限制，这是因为在固化过程中形成了许多微孔和缺陷，导致其阻隔性能较差。在此，通过直接向水性环氧树脂乳液中添加 0.2-1.0wt%的纤维素纳米晶体（CNC），然后添加胺固化剂并进行喷涂涂覆，制备了纤维素纳米晶体（CNC）增强的水性环氧树脂涂料。添加 0.2-0.5wt%的 CNC 对水性环氧树脂乳液的稳定性没有明显影响。这导致 CNC 在固化涂层基质中均匀分散，这可以通过差示扫描量热分析得到证明。由于良好的相容性，0.2-0.5wt% CNC 增强的环氧树脂涂层对钢表现出优异的腐蚀保护性能。这些涂层在浸入 3.5wt%NaCl 溶液 21 天后，阻抗模量仍保持在 10Ωcm。CNC 表面的羟基与环氧基团发生反应，增强了分子间相互作用，形成了无缺陷的致密结构，提高了涂层的阻隔性能。然而，加入过多的 CNC（即 0.8 和 1.0wt%）会由于聚集诱导的涂层缺陷而显著降低环氧树脂涂层的耐腐蚀性。总的来说，本研究为提高水性环氧树脂涂料的耐腐蚀性提供了一种简便、绿色的策略。
