4ZnO·B_2O_3·H_2O的微波水热合成与表征

Microwave-hydrothermal Synthesis and Characterization of 4ZnO·B_2O_3·H_2O

硼酸锌是一种新型高效无机阻燃剂。为了优化制备硼酸锌的反应条件并研究其阻燃性能,以七水硫酸锌和硼砂为原料,采用微波水热法合成硼酸锌(4ZnO·B_2O_3·H_2O),通过XRD、SEM、TG-DTA进行表征并对其阻燃性能进行测试。优化后的实验条件为:锌与硼砂物质的量的比为1∶1.2,固液质量比为1∶10,140℃下微波水热反应时间为10min。该条件下所得硼酸锌的失水温度高于415℃,形貌呈不规则片状,厚度约为100nm;添加质量分数为10%的该样品于木屑中,400℃时的残碳率与纯木屑样品相比高约27%。在制备硼酸锌过程中,添加硬脂酸钠或含有硬脂酸钠的复配修饰剂后,改性效果均较好,所得样品亲油疏水,且样品形貌有变化。其中同时添加硬脂酸钠和聚乙二醇所得样品为分散较均匀的纳米棒,直径为50~80nm。

Zinc borate is a new and efficient inorganic fire retardant. Study of the optimal reaction conditions for preparing the zinc borate and its flame--retardant property is of vital significance. In this research, zinc sulfate heptahydrate and borax were used as raw materials to synthesize zinc borate 4ZnO · B2O3 · H2O via the microwave hydrothermal method. It was analyzed by XRD, SEM, TG-DTA, and its flame-retardant property was tested. The optimized experimental conditions are as follows： the molar ratio of zinc sulfate and borax is 1 ： 1.2, the solid-liquid mass ratio is 1 ： 10, and the microwave hydrothermal reaction time is 10 min at 140 ℃. Under these conditions, the resultant zinc borate has a dehydration temperature higher than 415 ℃, flaky morphology and sample thickness of about 100 nm. With 10% of the sample in the wood, the char yield at 400 ℃ is about 27% higher than that of pure wood sample. After adding sodium stearate or modifying agent containing sodium stearate complex into the reaction process, the modification effects were good with the resulting sample lipophilic and the sample morphology changed. By adding sodium stearate and polyethylene glycol, the resulting samples were dispersed more uniform nanorod and the diameter was about 50-80 nm.