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硼酸根插层的Ca-A1LDHs的制备、改性与应用研究
Study on the Preparation,Modification and Application of Borate-pillared Hydrotalcites
【作者】 王娜；
【导师】 仲剑初；
【作者基本信息】 大连理工大学 ， 功能材料化学与化工， 2015， 硕士
【摘要】 水滑石、类水滑石和插层水滑石等统称为水滑石类插层材料(LDHs)。目前有关Zn-Al-BO3-LDHs、Mg-Al-BO3-LDHs和Zn-Al-CO3-LDHs、Mg-Al-CO3-LDHs等LDHs的合成已有报道,并证明这些LDHs具有比较好的阻燃性。本文在前人研究工作的基础上,首先以四水硝酸钙、九水硝酸铝、氢氧化钠以及硼酸或硼砂为原料,探索适宜的合成方法和最佳的合成条件,合成硼酸根插层的Ca-Al-BO3-LDHs;其次使用表面改性剂和偶联剂对硼酸根插层的Ca-Al-BO3-LDHs表面进行有机化修饰；最后将改性后的硼酸根插层的Ca-Al-BOs-LDHs添加到EVA中,测试不同填充量下的EVA复合材料的力学性能和燃烧氧指数,考察硼酸根插层的Ca-Al-BO3-LDHs的阻燃效果。具体内容如下：(1)以四水硝酸钙、九水硝酸铝、氢氧化钠以及硼酸或硼砂为原料,首先采用常用的共沉淀的方法,在室温下将硼酸溶液和氢氧化钠溶液同时滴加到四水硝酸钙和六水硝酸铝的混合盐溶液中,然后将形成的乳白色浆液置于65℃的油浴中进行晶化,晶化时间控制为10h,晶化完成后再将该浆液在室温下静置13h。为探究该方法的最佳合成条件,又分别改变晶化温度和晶化时间,并对不同反应条件下的产物进行了XRD和FT-IR表征。通过分析发现该方法虽能获得硼酸根插层的Ca-Al-LDHs,但同时会有大量的副产物生成,并且获得产物的晶相不是很好。为此改变合成方法,即采用离子交换法来合成硼酸根插层的Ca-Al-LDHs,通过对该法合成产物的FT-IR和XRD分析表征,发现利用该方法可以得到比较纯净的硼酸根插层的Ca-Al-LDHs,最终确定离子交换法为硼酸根插层的Ca-Al-LDHs的适宜合成方法。(2)以上述合成方法和合成条件合成的产物为原料,对其先用硬脂酸进行表面改性,再加入钛酸酯偶联剂对其进一步进行表面改性,提高其与高聚物分子的相容性；对改性产物进行XRD. FT-IR表征,悬浮性能和活化指数测试,当偶联剂添加量为1%NDZ-311时,活化指数可达到97.86%。将改性粉体与EVA基体共混,获得硼酸根插层Ca-Al-LDHs/EVA复合材料。对其进行力学性能和氧指数测试表明：当1%NDZ-311改性的硼酸根插层的Ca-Al-LDHs与EVA以2：5的比例共混,混合后的复合材料平均拉伸强度为9.68MPa,平均断裂伸长率为663.3%；氧指数为27.8%；
【Abstract】 Hydrotalcite, hydrotalcite-like compounds and intercalated hydrotalcite are collectively referred to as hydrotalcite (LDHs) intercalated materials.Early, the LDHs such as zinc-aluminium-borate LDHs, magnesium-aluminium-borate LDHs and zinc-aluminium-carbonate LDHs, magnesium-aluminium-carbonate LDHs etc are synthesized successfuly. And these LDHs have already been proved that their flame retardancy efficiency are good.And on the basis of previous research work, this paper firstly use calcium nitrate tetrahydrate, aluminum nitrate nanohydrate, sodium hydroxide and boric acid or borax as raw material, through exploring the best synthesis method, the optimum synthesis conditions to successfully synthesise borate-pillared hydrotalcite, and then using surface modification agent and coupling agent to modified it;Finally the modified borate-pillared hydrotalcite is added to EVA, and test the burning oxygen index of composite to explore flame retardant efficiency of borate-pillared hydrotalcite.Specific content is as follows:(1)With calcium nitrate tetrahydrate, aluminum nitrate nanohydrate, sodium hydroxide and boric acid or borax as raw material, firstly adopts the common method-coprecipitation as synthesis method, solutions of boric acid and sodium hydroxide solution were added simultaneously to the mixed salt solution ofnitrate tetrahydrate and aluminum nitrate nanohydrate at room temperature, and then the formation product-milky white slurry was placed in the oil bath which temperature is 65℃ for crystallization, crystallization time is 10 h, after crystallization the slurry was placed in room temperature for 13h.To explore the optimum synthesis method and conditions, change the crystallization temperature and time respectively to synthesize products, and products of different reaction conditions were characterized by XRD, FT-IR, through the analysis found that this method can get borate-pillared hydrotalcites, but there will be a lot of by-products generated at the same time, and the product phase is not very good.Then,using ion exchange method to synthesized borate-pillared hydrotalcites, through the analysis of the FT-IR and XRD characterization results of synthetic product, found that using this method can get more pure borate-pillared hydrotalcites, so ion exchange method is the optimum synthesis method.(2) Using the product which synthesized by the optimum methods and synthesis conditions as the raw material, using stearic acid to modified its surface, adding silane coupling agent for the further surface modification, to improve its compatibility with polymer molecules;Modified products were characterized by XRD, FT-IR, suspension property, activation index test, and when the adding amount of coupling agent was 1% NDZ-311, the activation index can up to 97.86%.The modified powder was added to EVA matrix, and getted the borate-pillared hydrotalcites/EVA composites. The mechanics performance test and the oxygen index test showed that the modification borate-pillared hydrotalcites by 1% NDZ-311 blending with EVA at the ratio of 2:5, the blending composite average tensile strength is 9.68MPa, on average, the elongation at break is 663.3%;Oxygen index is 27.8%;