Structural and Morphological Characteristics of Polyaniline Synthesized in Pilot Scale

ABSTRACT: Polyanilines have many applications in Aerospace, especially in their doped form. Studies on their synthesis in a pilot scale can contribute to obtain products with desirable characteristics for such applications. The present study reports the chemical oxidative synthesis of polyaniline in pilot scale and different reaction times in order to determine if there are variations in the polyaniline structure, morphology and conductivity due to these synthesis conditions. It is very common to analyze these data for polymers obtained through bench scale. However, several parameters change the properties of final material in major scales, such as thermal, mechanic and diffusive variables. Therefore, the reaction time is the only variable into the 9 syntheses carried out, and polyaniline is obtained in a doped form, being dedoped with ammonium hydroxide and redoped with dodecylbenzenesulphonic acid. The doped and redoped samples were characterized by their molecular structure, thermal behavior, crystallinity and morphology. The electrical conductivity of redoped samples was determined. Some differences in the structure and morphology of doped and dedoped forms, identifying the doping structures, were reported. This paper aims to present the relationship between changes on structure and morphology of doped and undoped polyaniline obtained by the mentioned experiments. Furthermore, some addicts on conductivity are carried out. It was possible to contribute in order to obtain a more conductive polyaniline in pilot scale.摘要：聚苯胺（polyaniline）在航空航天领域拥有广泛应用，其中掺杂态（doped form）聚苯胺的应用尤为突出。开展中试规模下聚苯胺合成工艺的相关研究，有助于制备出适配航空航天应用需求的高性能产物。本研究通过化学氧化法开展了中试规模下、不同反应时间的聚苯胺合成实验，以探究合成条件对聚苯胺结构、形貌与导电性能的影响。针对实验室规模合成的聚合物的相关数据分析较为常见，但当合成规模放大至工业级时，热学、力学及扩散等多项参数会显著改变最终材料的性能。因此，本次开展的9组合成实验仅以反应时间作为单一变量，所得产物均为掺杂态聚苯胺，先经氢氧化铵（ammonium hydroxide）脱掺杂，再以十二烷基苯磺酸（dodecylbenzenesulphonic acid）进行二次掺杂。研究人员对掺杂态与二次掺杂态样品的分子结构、热性能、结晶度及形貌进行了表征，并测定了二次掺杂态样品的导电性能。本研究还分析了掺杂态与脱掺杂态聚苯胺在结构与形貌上的差异，明确了其掺杂结构。本文旨在阐明上述实验所得掺杂态与未掺杂态聚苯胺的结构、形貌变化之间的内在关联。此外，本研究还开展了针对导电性能的相关分析。本研究可为中试规模下制备高导电性能聚苯胺提供有益参考。