Blendas de polianilina e poliestireno obtidas por processamento reativo : preparação e caracterização

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

One of the major current objectives in the research of intrinsically conducting polymers (PIC) is the production of blends, which combine the processing properties of common thermoplastic polymers with the conductivity of conducting polymers. The main problem in applying PIC in large scale in the plastic industry has been the infusibility of these polymers, but nowadays there are methods capable to solve this problem, like the use of functionalized acids that improve the thermal stability and processability of conductive polymers. In this work the doping process was carried out during the processing, eliminating several steps, this is also denoted by "reactive processing". The complex PAni-DBSA (polyaniline doped with dodecylbenzene sulfonic acid) was used to study the influence of addition of the poly(styrene) sulfonic acid, PSS during the processing in a internal mixer. This acid was used to improve the dispersion of the complex PAni-DBSA and also as compatibilizer in the blends processing involving the thermoplastic polystyrene, PS. Conductive thermoplastic blends of PS and PAni-DBSA-PSS were prepared in a double screw counter rotatory internal mixer coupled to a Haake Rheocord torque rheometer. We used SBS (styrene-butadiene-styrene) as compatibilizer and different formulations were tested according to a statistical response surface method. The blends were characterized by thermal analyses (TGA, DSC and DMA), scanning electron microscopy (SEM), electrical conductivity (Four probe and ASTM D257-66 methods) and radiation reflectivity measurements. The concentration of the compatibilizer, PAni and the blends thickness affect material performance as radiation absorber. The reactive processing of PS/SBS/PAni-DBSA-PSS blends was also carried in the double-screw extruder, in order to obtain the conductive thermoplastic (s = 10 to 10 S.cm) in the form of strips to evaluate the mechanical properties (ASTM D882-95a). Our results clearly demonstrate that PS/SBS/PAni-DBSA-PSS blends are very promising to applications such as electromagnetic radiation absorption in the microwave range 8-12GHz) for radar absorbing materials (RAM).

ASSUNTO(S)

polimerização termoplasticos polimeros condutores

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