反应物中氧化剂和掺杂剂浓度对聚苯胺性能与结构的影响

采用红外光谱、X射线衍射、透射电子显微术结合电导率测量,研究了以过硫酸铵为氧化剂,十二烷基苯磺酸为掺杂剂,通过乳液聚合法合成的聚苯胺的性能与结构.实验中发现:聚苯胺的电导率随合成时氧化剂、掺杂剂与苯胺相对比例的改变而发生明显变化,并在某一比例达到峰值,同时伴随有红外光谱某些特征峰峰位与峰高的相对变化,而晶化程度也随合成条件不同而呈现差异,性能最佳的聚苯胺的微观形貌呈纤维状,对应于最大的晶化程度,接近于中间氧化态.这些结果表明:氧化与掺杂条件的变化影响到聚苯胺中苯环与醌环的相对比例、聚苯胺链的排列有序度,而这些也是影响聚苯胺电导率的重要因素.

Concentration effect of oxidant and doping agent on structure and properties of polyaniline

Infrared spectrum, X-ray diffraction, transmission electron microscopy and conductivity measurement were employed to investigate the properties and structure of polyaniline samples, which were synthesized by emulsion polymerization with different concentrations of ammonium peroxydisulfate and dodecyl-benzene sul-phonic acid. The electrical conductivity of polyaniline varied with the molar ratio of oxidant and doping agent to aniline and reached peak at some value, while some characteristic peak values at their infrared spectrum changed their location and intensity relatively. The crystallization degree of different samples exhibited distinction due to different synthesis conditions. Under the optimum synthesis condition, a fibril morphology and higher crystallinity were observed. The results indicate that the change of oxidation and doping condition affects the ratio of benzenoid to quinoid ring and the orientation order of the polyaniline chain, which are important factors to decide the conductivity of polyaniline.