Abstract
Magnetic iron nanoparticles are attracting a great deal of research and application interest in diversified fields. In this present investigation, iron nanoparticles were prepared by a in-situ chemical reduction technique in a combination of polyaniline (PANI)-polyacrylamide (PA) and PANI-hyperbranched polyurethane (HBPU) matrices to judge the suitability of hyperbranched system. The formation of the nanoparticles in polymer matrices has been investigated by FTIR, UV, XRD, SEM and TEM studies. Narrower size with better dispersion and more stable nanoparticles were found in a hyperbranched matrix system compared to a linear one. The particle size was found to be in the range of 10–20 nm and 12–35 nm in HBPU-PANI and PA-PANI matrices, respectively. Both the nanocomposites exhibit synergistic free radical scavenging capability towards 2,2-diphenyl-1-picrylhydrazyl (DPPH). The magnetic hysteresis loop of the nanocomposites indicates the super-paramagnetic behavior. The hyperbranched system is more thermostable than the linear system by 70°C.
Acknowledgements
The authors express their gratitude and thanks to the research project assistance given by DST, India through the grant No. SR/S3/ME/13/2005-SERC-Engg, dated 9th April, 2007. Also, Mr. Gitanjal Deka thanks the Coordinator, Nanoscience and Technology, Department of Physics, Tezpur University. RSIC, NEHU, Shillong and CIF, IIT Guwahati are thankfully acknowledged for the TEM imaging and magnetometric analysis, respectively.