Transparent intumescent fire-retardant (IFR) coatings are the newest passive fireproofing materials which maintain structural integrity without losing aesthetic appearance of the substrate. In this present paper, effects of three IFR coatings with structurally different epoxy resins, namely aliphatic, cycloaliphatic, and aromatic, on the fire resistance, transparency, and physicomechanical properties were investigated. Different phosphate resin acids (PRA) were prepared by reacting synthesized phosphate ester acid (PEA) with aliphatic, cycloaliphatic, and aromatic epoxy resins. The chemical structures of the above PEA and PRAs were confirmed by Fourier transform infrared spectroscopy (FTIR), ¹H-nuclear magnetic resonance spectroscopy (¹H-NMR), and ³¹P-nuclear magnetic resonance spectroscopy (³¹P-NMR). Subsequently, transparent IFR coatings were prepared by mixing these PRAs with hexamethoxy methyl melamine resin. Transparency of the coatings was confirmed by UV–Vis–NIR spectrophotometeric studies. Fire protection property and char compressive strength were done to investigate the fire protection ability of the coatings, and the quality of the char formed was analyzed by field emission scanning electron microscope. The decomposition process of prepared fire-retardant coatings was studied by thermogravimetric analysis. Results showed that aliphatic epoxy-based transparent coating produced tough and compact char, but the char height was negligible, and aromatic epoxy-based transparent coating produced soft and fluffy char having excellent char height; however, the fluffy char reduced protection for longer duration. Cycloaliphatic epoxy-based transparent coating produced tough and compact char with good char height, thereby reducing heat transfer during combustion, and also showed superior scratch, abrasion, impact, and water resistance compared to other compositions.

透明膨胀型防火（IFR）涂料是最新的被动防火材料，可保持结构完整性而又不损失基材的美观外观。在本文中，研究了三种结构不同的环氧树脂（脂族，脂环族和芳族）的IFR涂层对耐火性，透明度和物理机械性能的影响。通过使合成的磷酸酯酸（PEA）与脂族，脂环族和芳族环氧树脂反应，可以制备不同的磷酸酯酸（PRA）。通过傅里叶变换红外光谱（FTIR），¹ H核磁共振光谱（¹ H-NMR）和³¹证实了上述PEA和PRA的化学结构。对核磁共振波谱（³¹P-NMR）。随后，通过将这些PRA与六甲氧基甲基三聚氰胺树脂混合来制备透明的IFR涂层。紫外-可见-近红外分光光度计研究证实了涂层的透明度。通过防火性能和炭抗压强度研究涂层的防火性能，并通过场发射扫描电子显微镜分析所形成炭的质量。通过热重分析研究了制备的阻燃涂料的分解过程。结果表明，脂族环氧基透明涂料可制得坚韧致密的焦炭，但焦炭高度可忽略不计，而芳族环氧基透明涂料可制得柔软且蓬松的焦炭高度优异的炭。但是，蓬松的炭会降低保护的持续时间。