Chen Sin-Nan, Li Pei-Kai, Hsieh Tar-Hwa, Ho Ko-Shan, Hong Yu-Meng
Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, Kaohsiung City 807618, Taiwan.
Department of Chemistry, National Cheng Kung University, No. 1, University Road, Tainan 70101, Taiwan.
Materials (Basel). 2021 Nov 3;14(21):6628. doi: 10.3390/ma14216628.
Flame-retardant coatings have drawn much attention in recent years. In this study, an inorganic sodium silicate-based intumescent flame-resistance coating with an excellent flameproof properties is developed by mainly utilizing sodium silicate as the ceramizable binder, via hydrolysis and self-condensation reaction. Fly ash, metakaoline, and wollastonite behave as supplement cementing materials. Major formulation encompasses the combination of the ammonium polyphosphate and pentaerythritol as the flame-retardant additives, and aluminum hydroxide or expandable graphite as the intumescence-improving filler agents. Expandable graphite was found to play an important role in the eventual performance of flame-resistance testing. The results showed that solid interaction forces can be formed between metakaoline and sodium silicate, resulting in a similar material to geopolymer with excellent physical properties. After high-temperature flame testing, a densely complex protective layer of carbon-char created on top of the robust silicon dioxide networks offers notable flame resistance. An optimal ratio in this inorganic intumescent coating contains sodium silicate-metakaoline (weight ratio = 9:1)-ammonium polyphosphate and pentaerythritol, aluminum hydroxide (3, 3, 10 wt.%)-expandable graphite (1 wt.%), which can create 4.7 times higher expansion ratio compared with neat sodium silicate matrix. The results of flame testing demonstrate only 387.1 °C and 506.3 °C on the back surface of steel substrate after one and three hours flaming (>1000 °C) on the other surface, respectively, which could meet the requirements according to the level of fire rating.
近年来，阻燃涂料备受关注。在本研究中，主要以硅酸钠为可陶瓷化粘结剂，通过水解和自缩聚反应，开发出一种具有优异防火性能的无机硅酸钠基膨胀型防火涂料。粉煤灰、偏高岭土和硅灰石作为辅助胶凝材料。主要配方包括聚磷酸铵和季戊四醇作为阻燃添加剂的组合，以及氢氧化铝或可膨胀石墨作为膨胀增强填充剂。发现可膨胀石墨在最终的阻燃测试性能中起重要作用。结果表明，偏高岭土和硅酸钠之间可形成固体相互作用力，从而形成一种类似于地质聚合物的材料，具有优异的物理性能。经过高温火焰测试后，在坚固的二氧化硅网络顶部形成的致密复杂的碳-炭保护层具有显著的阻燃性。这种无机膨胀型涂料的最佳配方包含硅酸钠-偏高岭土（重量比=9:1）-聚磷酸铵和季戊四醇、氢氧化铝（3、3、10重量%）-可膨胀石墨（1重量%），与纯硅酸钠基体相比，其膨胀率可提高4.7倍。火焰测试结果表明，在钢基材另一面进行一小时和三小时燃烧（>1000℃）后，钢基材背面的温度分别仅为387.1℃和506.3℃，根据防火等级要求，这可以满足要求。
