EMI shielding response of polypyrrole-MWCNT/polyurethane composites

Composites based on thermoplastic polyurethane [TPU] as matrix and polypyrrole/MWCNT (PCNT) as filler were prepared which inherit conducing, dielectric and magnetic attributes of polypyrrole/MWCNT [PCNT] filler. Polypyrrole/MWCNT was synthesized by in-situ polymerization of pyrrole monomer by chemical oxidative method in presence of MWCNT and fabrication of composites was carried out using solution blending method. The effect of polypyrrole /MWCNT content on electrical and microwave shielding efficiency of TPU was investigated to evaluate their potential as an effective EMI shield. These composites show absorption dominated total shielding effectiveness (SET) up to - 46 dB in frequency range of 8.2-12.4 GHz (X-band) suggesting their utility for microwave absorbers. The EMI shielding result was also compared with polyurethane composites using neat polypyrrole (PPy) as filler. Polyurethane composites prepared using PCNT as filler showed much higher shielding efficiency (-46 dB using 40 wt. % PCNT filler) as compared to polyurethane composites having only PPy as filler (-18 dB using 40 wt. % PPy filler).