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By 肖学山


聚合物是一类软物质,软物质最典型的特征是对外场的影响易于作出响应。在外场如电场、磁场、温度场和微重力场等作用下,其内部结构会发生一系列变化,对于聚合物其分子链的构象及分子链的堆积等均有可能发生转变。通过控制外场类型和强度可以实现对聚合物材料结构的调控,从而使聚合物材料的功能能适应外界条件的变化,满足不同环境的需要。外场对聚合物形成的影响是目前聚合物材料研究的一个热点。本文目的是研究高真空强静电场对聚合物结构和形态的影响,在自行设计制造的高真空强静电场装置上进行了聚合物熔融结晶、共混物半熔融态处理和聚合物薄膜微晶生长实验,使用XRD、DSC和SEM等研究手段对上述实验样品进行了分析和观察,实验发现,随静电场强度的增大,熔融结晶的等规聚丙稀和间规聚苯乙稀的XRD峰均向低角度偏移,导致等规聚丙稀晶格参数增大,晶胞膨胀,而间规聚苯乙稀逐渐由α型向β型转变,等规聚丙稀随静电场强度的增大,逐渐由球晶变为沿电场方向取向的厚片晶,间规聚苯乙稀由混乱的片晶变为有取向规整的片晶;在强静电场下,半熔融处理的PA11/PVDF共混物,随电场强度的增加,PA11逐渐由α型向δ型转变,共混物由球晶逐渐变为沿电场方向取向的柱状晶;同样,随电场强度的增加,聚合物薄膜微晶由树枝形球晶转变成沿电场方向取向的树枝晶,且在强静电场下部分聚合物的树枝发生断裂。总之,在聚合物固化过程中施加强静电场将对聚合物的结构和形态转变产生较大的影响。Polymer is a kind of soft matter whose typical characteristic is easy to respond to turbulence of external fields. The conformation and packing of polymer chains may be transited in such external fields as electric field, magnetic field, thermal field, micro-gravity and so on. The mode and strength of the external field could control the morphology and structure of polymer materials, so that various functions of polymer materials could be achieved to meet the requirements of different environments. At present, the effect of external fields on polymer formation has become an important issue in the development of polymer materials. The purpose of this dissertation is to study the effect of high vacuum strong electrostatic field on the structure and morphology of polymers. Melt-crystallization of polymer, semi-melt treatment of blends and micro-crystal growth of polymer films in a high vacuum strong electrostatic device designed by author have been investigated by using Wide angle X-ray Diffraction (WAXD), differential scanning calorimetry (DSC) and Scanning Electron Microscopy (SEM). The results of isotactic polypropylene melt-crystallization show that crystallographic parameters increase with increase of electrostatic intensity, and the crystal orientation and variation of the crystalline morphology from spherulites to lamellar crystals was found. The results of syndiotactic polystyrene melt-crystallization show that syndiotactic polystyrene gradually changed from α phase to βphase, and the morphology was transformed into the ordered lamellar crystals with increase of electrostatic intensity. PA11 of semi-melt PA11/PVDF blends in a strong electrostatic field gradually changed from α phase to δ phase, and the crystal orientation and variation of the micro-crystals from spherulites to cylinder crystals with increase of electrostatic intensity were observed. The experiment results of polymer films treating in an electrostatic field show that the main stem of dendrite crystals were parallel to the direction of electrostatic field, and some branches of poly(3-dodecylthiophene ruptured. In a word, the external electrostatic fields exert a strong influence on structure and morphology of polymer during solidification of polymers

Topics: 静电场, 聚合物, 结构, 形态, 高分子化学与物理
Year: 2000
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