为了研究水滑石及插层改性水滑石对膨胀型防火涂料耐紫外线性能的影响, 该研究制备了对照样件(#0)以及添加不同比例水滑石或插层水滑石的膨胀型防火涂料涂覆样件各5组, 进行了不同时长的紫外线照射, 并利用锥形量热仪、扫描电镜、热重分析仪和Fourier变换红外光谱分析仪对各样件性能进行分析。结果表明：相较于#0组的对照样件, 水滑石组和插层水滑石组样件的防火性能和耐紫外线性能显著提高, 插层水滑石组比水滑石组样件的性能提升幅度更大; 当插层改性水滑石的质量分数为2.7%时, 涂料具有最佳的阻燃性能。对插层改性水滑石的阻燃机理分析发现, 镁铝水滑石与膨胀型防火体系相结合, 构建了一种互穿网络结构, 在其层间插入有机阴离子(UV-326)具有吸收紫外线的功能, 镁铝水滑石分解后产生的碱性多孔复合氧化物与聚磷酸铵以及涂料的炭化产物结合形成保护层, 可有效阻隔热量和氧气的侵入, 起到增强阻燃的作用。

Objective: To better understand the influence of intercalated modified hydrotalcite on the ultraviolet resistance of intumescent fire-retardant coatings on wooden structures, this study is dedicated to exploring the flame-retardant properties of intumescent fire-retardant coatings with different mass fractions of hydrotalcite or intercalated modified hydrotalcite after ultraviolet exposure of different durations. The analysis focused on the performance and mechanisms of intercalated modified hydrotalcite. Methods: Experimental specimens were prepared, including a control specimen (#0), five groups of fire-retardant coating specimens containing different proportions of hydrotalcite, and five groups containing different proportions of UV326-intercalated modified hydrotalcite. The specimens were subjected to ultraviolet (UV) irradiation for different durations. Their properties were analyzed using cone calorimeter, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier-transform infrared spectroscopy (FTIR). Key fire-related parameters, such as ignition time, heat release rate, total heat release, effective heat of combustion, and total smoke release, were studied to assess performance differences. Results: Cone calorimeter tests revealed a significant improvement in the flame-retardant and UV-resistant properties of specimens containing hydrotalcite or intercalated modified hydrotalcite compared to the control group (#0). When the additive ratio was 2.7%, the aging rate decreased from 86% (#0) to 48% (hydrotalcite specimens) and 45% (intercalated modified hydrotalcite specimens), respectively. SEM analysis of the aged UV#3 (with 2.7% intercalated layered hydrotalcite) specimen, along with its expanded char layer, showed that intercalation modification effectively minimized hydrotalcite agglomeration in the coating. During the early stages of the UV aging process, the expanded char layer exhibited excellent performance, with a dense and thick structure, numerous pores, and a well-defined honeycomb-like pattern. With the extension of UV irradiation time, however, the char layer became increasingly fragmented and irregular. After 15 days, the control specimen (#0) was nearly incapable of forming a complete expanded layer. FTIR analysis indicated that UV aging treatment caused the decomposition of ammonium polyphosphate and polyacrylate resin in the flame-retardant system. The UV resistance of the intumescent fire-retardant coating with intercalated modified hydrotalcite was significantly enhanced. The inclusion of intercalated modified hydrotalcite caused the appearance of the C—N—C absorption peak, indicating the formation of a cross-linked structure between the amino groups in hydrotalcite and pentaerythritol. Conclusions: This study underscores the importance of optimizing the formulation and application of fire-retardant coatings to effectively reduce the fire risk of wooden structures. Properly designed coatings can slow the flame spread and control local temperatures, but inappropriate coating choices or application strategies may lead to risks such as UV aging and uneven fire protection. These findings provide important technical insights for developing fire safety measures, highlighting the need to tailor fire-retardant coating strategies to wooden structures. This study offers valuable scientific evidence for improving fire safety management in wooden structures and holds practical relevance for improving the design and application of fire-retardant coatings.