【摘要】 用共沉淀法制备了层间具有不同无机阴离子的镁-铝水滑石MgAl-X LDH (X=CO₃^2-、NO₃^-、Cl^-和SO₄^2-),采取X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）、X射线光电子能谱（XPS）、扫描电子显微镜（SEM）和BET比表面分析表征了所得样品的结构,通过吸附实验和热稳定实验考察了其对氯化氢（HCl）的吸附性和对聚氯乙烯（PVC）热稳定性的影响并探究了水滑石的热稳定机理。结果表明,所得水滑石具有较高的结晶度,呈规整的六边形薄片状,宽120～275 nm;层间阴离子对水滑石吸附HCl和PVC热稳定性影响较大,MgAl-CO₃LDH的吸附性能最好、吸附量可达54.2 mg/g,其次为MgAl-NO₃LDH和MgAl-ClLDH,MgAl-SO₄LDH最差。且水滑石吸附HCl量越大,对PVC的热稳定性能就越好。水滑石能提高PVC的热稳定性的机理主要是它能与PVC热降解过程中释放的HCl发生表面吸附和孔吸附,从而限制了HCl对PVC降解的自催化作用,使PVC的热稳定性能提升。更多还原

【Abstract】 Magnesium-aluminum hydrotalcites MgAl-X LDHs with four different interlayer inorganic anions( X = CO₃^2-,NO₃^-,Cl^-,and SO₄^2-) were prepared by co-precipitation method.The structure of the samples were characterized by X-ray diffraction（ XRD）,fourier transform infrared spectroscopy（ FTIR）,X-ray photoelectron spectroscopy（ XPS）,scanning electron microscope（ SEM） and specific surface analysis（ BET）.The effects of the samples on the adsorption of hydrogen chloride（ HCl） and the thermal stability of PVC were investigated by adsorption and thermal stability experiments,and the mechanism of thermal stability was explored.The results show that the obtained MgAl-X LDHs have the high crystallinitie and exhibit a regular hexagonal sheet shape with the width of about 120～ 275 nm.The interlayer counterion has a great influence on their adsorption of HCl and the thermal stability of PVC.MgAlCO₃ LDH has the best adsorption performance and the adsorption capacity could reach 54.2 mg/g,followed by MgAl-NO₃ LDH,MgAl-Cl LDH,and MgAl-SO₄ LDH is the worst.In addition,it is found that as the increase of the adsorption capacity of HCl onto MgAl-X LDH,the thermal stability of PVC/MgAl-X LDH composites could be better.The mechanism of hydrotalcites could improve the thermal stability of PVC is that the surface adsorption and pore adsorption of HCl released from the thermal degradation of PVC,which limits the autocatalytic dehydrochlorination and improves the thermal stability of PVC.更多还原