Studies on the mechanical electrical and thermal properties of Polythiophene coated banana fiber composites based on PU PE and PP

Abstract

In the present study a conducting polymer, polythiophene, was newlineprepared through chemical oxidation method. The preparation method newlinewas optimized for good conductivity and yield. The optimized method newlinewas employed for in situ polymerization of polythiophene on cellulosic newlinefibers extracted from banana stem, an agricultural waste biomass. newlinePolythiophene (PTH) and polythiophene coated fibers (PCF) were newlineincorporated in general purpose thermoplastic matrices viz. polypropylene newline(PP), polyethylene (PE) and thermoplastic polyurethane (TPU). The newlinematrices were selected based on increasing flexibility in the order newlinePPltPEltTPU with the aim of preparing flexible conducting composites. newlinePolythiophene coated fibers were expected to enhance conductivity of the newlinecomposites by attaining percolation threshold at lower loadings. The newlinecomposites were tested for electrical, mechanical, thermal and shielding newlinecharacteristics. Incorporation of polythiophene improved conductivity but newlinereduced mechanical properties. On the other hand, PTH coated cellulosic newlinefiber composites showed improved mechanical properties, but reduced newlineconductivity due to the presence of moisture in the fibers. PTH/PP and newlinePTH/PE composites showed significant improvement in thermal stability, newlinewhereas PTH composites of TPU decreased in thermal stability due newlineto hydrolytic degradation of the matrix. Both PTH and PTH coated newlinefibers enhanced dielectric constant of composites to exceptionally high newlinelevels making them promising candidates for capacitor applications. newlineElectromagnetic interference (EMI) shielding efficiency in X band of the newlinecomposites, especially that of PE showed tremendous improvement by newlinethe incorporation of PTH. The fact that the EMI shielding efficiency of newlinethe composites is almost entirely due to absorption make them ideal newlinematerials for microwave absorbers suitable for stealth applications. newline