镁铝水滑石PVC热稳定剂的合成研究

发布时间：2018-03-17 16:43

  本文选题：层状材料　切入点：水滑石　出处：《北京化工大学》2015年硕士论文　论文类型：学位论文

【摘要】：水滑石类化合物(LDHs)属于阴离子型层状材料,具有可调控金属阳离子二维层板,需要电荷补偿的层间区域,以及可交换的阴离子客体,绿色,低成本,可以作为高效的PVC热稳定剂新品种。本课题考察了合成原料、合成方式、合成温度、原料液配比、晶化处理条件等对合成碳酸根型镁铝水滑石结构和组成的影响。首先采用普通共沉淀-水热法,根据不同镁源和铝源、不同镁铝摩尔比、不同水热温度,制备出碳酸根型水滑石前驱体,并对合成产物进行测试和分析,考察不同实验条件对产物的作用和影响。根据实验结果确定出合适的镁源和铝源、镁铝摩尔比和水热温度。再利用新型过程强化设备一定-转子反应器,制备纯度高、分散性好、形貌规则的镁铝碳酸根型水滑石前体。对比研究两种方法制备的MgAl-CO3-LDHs材料性能的优异性。普通共沉淀-水热法试验中采用的镁源和铝源分别为Mg(NO3)2·6H2O、 Al(NO3)3·9H2O,MgCl2·6H2O、NaAlO2,沉淀剂选用Na2CO3、NaOH,考察的镁铝摩尔比为1.5、2.0、2.5、3.0,水热温度为140℃、160℃、180℃和200℃。分析实验结果,确定最佳的合成条件：镁源和铝源分别为Mg(NO3)2·6H2O、Al(NO3)3·9H2O,沉淀剂选用Na2CO3、NaOH,摩尔比Mg/Al=2.0,水热温度为1 60℃。再采用定-转子反应器制备MgAl-CO3-LDHs:在已得到的最佳合成条件下,研究了定-转子反应器的转速、产物在反应器中循环时间以及加料流量对反应产物的影响。试验中考察的定-转子反应器转速为500r/min、 1000r/min、1500r/min、2000r/min和2800r/min,浆料在反应器中的循环时间为0.5h、1.0h和1.5h,加料流量为100ml/min、200ml/min、300ml/min和400ml/min。通过实验表征及分析发现此状况下的最佳合成条件：定-转子反应器转速为2800r/min,浆料在反应器中的循环时间为1.5h,加料流量300ml/min。实验进一步对合成的水滑石进行了性能测试。将实验制备的水滑石作为热稳定助剂添加到PVC材料中,制备LDHs/PVC复合材料,测试其热稳定性。结果发现：普通共沉淀-水热法制备的水滑石添加到PVC材料里仅仅提高了PVC的初期着色性,并没有延长其热稳定时间。采用定-转子反应器制备的水滑石添加到PVC材料里,不仅提高了PVC的初期着色性,还大大延长了PVC材料的热稳定时间。
[Abstract]:Hydrotalcite compounds (LDHs) are anionic layered materials with adjustable metal cationic two-dimensional laminates, interlaminar regions requiring charge compensation, and exchangeable anionic guest, green, low cost, It can be used as a new kind of PVC heat stabilizer. In this paper, the synthetic raw materials, synthetic methods, synthesis temperature and the ratio of raw materials to liquid were investigated. The effect of crystallization conditions on the structure and composition of synthesized magnesia-aluminum hydrotalcite was studied. Firstly, common coprecipitation-hydrothermal method was used according to different magnesium and aluminum sources, different molar ratios of magnesium and aluminum, and different hydrothermal temperatures. The carbonate-type hydrotalcite precursors were prepared, and the synthetic products were tested and analyzed. The effects and effects of different experimental conditions on the products were investigated. According to the experimental results, the suitable magnesium and aluminum sources were determined. Mg-Al molar ratio and hydrothermal temperature. A new type of process strengthening equipment, rotor reactor, is used to prepare high purity and good dispersity. The properties of MgAl-CO3-LDHs materials prepared by two methods were compared and studied. The magnesium and aluminum sources used in the common coprecipitation-hydrothermal test were Mg(NO3)2 路6H _ 2O, Al(NO3)3 路9H _ 2O, MgCl _ 2 路6H _ 2O, NaAlO _ 2, Na2CO _ 3NaOH, respectively. The molar ratio of magnesium to aluminum is 1.5U 2.5U 3.0, and the hydrothermal temperature is 140 鈩，

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