合成参数对聚苯胺性能与结构的影响

Concentration effect on structure and properties of polyaniline

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(NH4)2S2O8为氧化剂、十二烷基苯磺酸(DBSA)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。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。

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