Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, Qinghai, China; Qinghai Engineering and Technology Research Center of Comprehensive Utilization of Salt Lake Resources, Xining 810008, Qinghai, China; University of Chinese Academy of Sciences, Beijing 10049, China.
Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, Qinghai, China; Qinghai Engineering and Technology Research Center of Comprehensive Utilization of Salt Lake Resources, Xining 810008, Qinghai, China; Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing 100190, China.
J Colloid Interface Sci. 2021 Jul 15;594:791-801. doi: 10.1016/j.jcis.2021.03.088. Epub 2021 Mar 18.
Epoxy resin (EP) is a polymer that is widely used in different aspects of life, but its flammability property limits its fields of applications. Most flame retardants at present cannot be applied practically in scale due to their toxicity, incompatibility in polymers, degraded mechanical property or high cost of raw materials and comprehensive preparation process. Layered double hydroxides intercalated by gluconic acid anion (GLDHs) may serve as a new approach. GLDHs with Mg/Al ratio of 3/1 and 2/1 were first coprecipitated with low-cost green reactants, MgCl·6HO, AlCl·6HO, NaOH and sodium gluconate. Their structures were confirmed by X-ray diffractions (XRD), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR) and elemental analysis; their thermal properties were analyzed by thermo gravimetric analysis (TGA). Composites containing 40 wt.% GLDHs were easily manufactured with normal magnetic stirring without any filler precipitation. The combustion properties of the composites filled with 40 wt.% GLDHs2 are as follows: the limit oxygen index (LOI) could rise to 29.8% from 25.2% of pristine EP; UL-94 can reach V-1 level with total burning time of only 12.1 s without dropping; compared to pristine EP, the heat release rate peak (PHRR) could drop to 30% with heavy decrease in the smoke production rate and CO production rate. Dynamic mechanical thermal analysis (DMA) tests showed that the addition of 40 wt.% GLDHs had little impact on the glass transition temperature of the composites and could slightly improve their rigidity and toughness. Tensile strength of the composites filled with 40 wt.% GLDHs2 was almost close to 88% of the tensile strength of pristine EP. Above all, GLDHs with good compatibility in polymers can serve as a promising environmental friendly and low-cost flame retardant for EP and other heterochain polymers.
环氧树脂（EP）是一种广泛应用于生活各个方面的聚合物，但它的易燃性限制了其应用领域。目前，大多数阻燃剂由于其毒性、与聚合物的不兼容性、机械性能下降或原材料和综合制备工艺成本高，无法实际大规模应用。层状双氢氧化物被葡萄糖酸阴离子插层（GLDHs）可能是一种新方法。首先，用低成本的绿色反应物 MgCl·6HO、AlCl·6HO、NaOH 和葡萄糖酸钠共沉淀合成 Mg/Al 比为 3/1 和 2/1 的 GLDHs。通过 X 射线衍射（XRD）、透射电子显微镜（TEM）、傅里叶变换红外光谱（FTIR）和元素分析确认其结构；通过热重分析（TGA）分析其热性能。用普通的磁力搅拌很容易制备含有 40wt% GLDHs 的复合材料，没有任何填料沉淀。填充 40wt% GLDHs2 的复合材料的燃烧性能如下：极限氧指数（LOI）从纯 EP 的 25.2%上升到 29.8%；UL-94 可达到 V-1 级，总燃烧时间仅为 12.1s，无滴落；与纯 EP 相比，热释放率峰值（PHRR）可降低到 30%，同时烟雾产生率和 CO 产生率大幅降低。动态力学热分析（DMA）测试表明，添加 40wt% GLDHs 对复合材料的玻璃化转变温度影响不大，可略微提高其刚性和韧性。填充 40wt% GLDHs2 的复合材料的拉伸强度几乎接近纯 EP 的 88%。总之，与聚合物相容性好的 GLDHs 可作为一种有前途的环保、低成本阻燃剂，用于 EP 和其他杂链聚合物。
