【作者】 王政军；

【导师】 张玉军； 郑永杰；

【作者基本信息】 哈尔滨理工大学 ， 材料工程， 2007， 硕士

【摘要】 本文中，用聚乙烯砒咯烷酮和十六烷基三甲基氯化铵处理蒙脱土原土得到有机蒙脱土，分别简写为PVP-MMT及HD-MMT。为了达到更好的插层效果，选用PVP-MMT然后用熔融插层法制备出聚乙烯-乙烯醇／有机蒙脱土纳米复合材料(EVOH／PVP-MMT)。采用X-射线衍射(XRD)、原子力显微镜(AFM)、差示扫描量热法(DSC)分别研究了有机化蒙脱土的组成、纳米复合材料的相态、形貌及结晶行为，同时研究了复合材料溶剂阻隔性和流变性能。XRD表明聚合物基体已经插入到有机蒙脱土片层间；复合体系中蒙脱土含量越小，插层蒙脱土间距越大；当复合体系中有机蒙脱土含量≤8％时，形成剥离型纳米复合材料；当有机蒙脱土含量在8％～15％时，形成插层型纳米复合材料；当有机蒙脱土含量大于15％时，复合材料中蒙脱土片层间距无明显变化。AFM表明EVOH／PVP-MMT8％复合材料中PVP-MMT分布均匀且有较光滑的表面。EVOH／蒙脱土复合材料中有类晶区存在，整个EVOH／蒙脱土复合材料呈现一种大尺度的有序性。DSC显示经季铵盐处理过的蒙脱土片层在EVOH／有机蒙脱土纳米复合材料结晶过程中的异相成核作用不明显。在相同结晶条件下，EVOH／PVP-MMT纳米复合材料的结晶速率比EVOH慢：由于MMT的加入使得EVOH／PVP-MMT纳米复合材料的熔融温度(Tm)从EVOH 180.7℃降低到175.2℃，结晶温度(T_c)从EVOH157.9℃降低到153.1℃，而玻璃化转变温度(T_g)却较EVOH升高了大约2.6℃。EVOH／蒙脱土纳米复合材料性能测试表明，有机蒙脱土含量为5％、10％的EVOH／PVP-MM／复合材料对水的阻隔性比EVOH提高大约3.3％；当蒙脱土的含量为20％时，EVOH／PVP-MMT复合材料对水的阻隔性的提高不明显。流变试验表明加工温度在200℃以上，转速20rpm左右，挤出物料表面光滑，韧性优良；EVOH／PVP-MM7插层复合材料熔体为假塑性流体，剪切速率增加，表观粘度下降，即存在剪切变稀现象；有机化蒙脱土含量增加，熔体流动性下降，粘度升高；EVOH／PVP-MMT插层复合材料熔体的表观粘度随温度的升高而降低，蒙脱土含量增加，熔体对温度的敏感性下降。更多还原

【Abstract】 In the thesis, the montmorillonite (MMT) was treated by polyvinyl pyrrolidone and hexadecyl quaternary ammonium salt respectively to get two kinds of montmorillonite with good intercalation written as PVP-MMT and HD-MMT, and then the ethylene-vinyl alcohol copolymer (EVOH)/PVP-MMT nano-composites were prepared by dynamic melt blending. The phase morphology as well as the crystallization behavior of the nano-composites were characterized by using X-ray diffraction (XRD), atomic force microscope (AFM) and differential scanning calorimetry (DSC).XRD indicate that EVOH intercalate into the galleries of montmorillonite, the less content of PVP-MMT, the larger of interlamellar spacing will be. When the content of PVP-MMT is 8%, the exfoliated nano-composites are produced, and the intercalated nano-composites could be prepared as the content is 15%. Additionally, the interlamellar spacing has no clear changes after PVP-MMT content exceeds 15%. AFM indicate that the nanocomposites with 8% PVP-MMT have a more uniform distribution and smooth surface than nanocomposites containing 20% PVP-MMT. The interaction between polymer matrix and MMT observed in nanoscale is obtained, from which the analogical crystallization was found in these micrographs, and the nanocomposites expose ordering structure due to the ordered segment of EVOH. The result of DSC shows that the heterogeneous nucleation acting of montmorillonite lamella treated by quaternary ammonium salt in the crystallization process is not distinct. In same condition, the rate of crystallization of EVOH/PVP-MMT is higher than that of EVOH. The Tc of the nanocomposites decreases from 159.7℃(EVOH) to 153.1℃, and the T_m decreases from 180.7℃to 175.2℃due to the mixing of MMT. However, the T_g of EVOH/PVP-MMT increases about 2.6℃comparing with that of EVOH. The water resisting property of the nanocomposites with 5%, 10% PVP-MMT increase 3.3% comparing to that of neat EVOH, which is good for barrier property as the EVOH/PVP-MMT nanocomposites using as packing materials. What is over, the relative adsorption quantity of water have a little change when the PVP-MMT content reach 20% in nanocomposites. The extrusive material is smooth and its performance is good, when the temperature is set at above 200℃and the shear rate at about 20rpm; The melt of EVOH/PVP-MMT composite is a type pseudoplastic fluid, and the viscosity decreases with the increase of the shear rate, which is a shear-thinning phenomenon; The flowing property decreases and the viscosity increases, when the amount of montmorillonite increases; The viscosity of EVOH/PVP-MMT composite decrease with the increase of the temperature, and the change is puny, so the material can be machininged in wide temperature.更多还原