Synthesis and study of electroactive nanoparticles and their polymer composites for novel applications

Abstract

Polymer ceramic composites using a polymer binder, nanosized BaTiO 3 and metal particles were developed for radiation shielding in the microwave region. From X-ray Diffraction (XRD) the crystallinity and nanosize of BaTiO 3 was confirmed in the composite. Interesting changes in Differential Scanning Calorimetry (DSC) were observed before and after ball milling of BaTiO 3 . Shielding Efficiency (SE) of microwave radiation has been measured from transmitted fraction (TF) of electromagnetic waves (EM) at different frequencies. The changes in TF were assigned to reflection and absorption of EM waves in different composites.

Modifications of polymers by additives and irradiations and their characterizations

“…Barium titanate (BaTiO 3 ) with perovskite structure has a high dielectric constant of κ = 7000, compared to κ = 9 for alumina, for example. Barium titanate (BTO) is a ferroelectric showing piezoelectric effect up to its Curie temperature of about 127 ° C [3] . For making the shielding composites, single phase BTO was prepared in-house from BaCO 3 and TiO 2 powders using solid state reaction mechanism, by fi ring at ∼ 1400 ° C for a total time interval of 12 h, and characterized using x-ray diffraction (XRD), transmission electron spectroscopy (TEM) and DSC.…”

“…Electric or magnetic dipoles in the shield material can absorb EM waves. EMI shielding measurements over 700 MHz-40 GHz range have been done with a vector network analyzer [3,4] on polymer-metal, polymer-inorganic and mixed composites.…”

Polymer Composites for Flexible Electromagnetic Shields

“…These are piezoelectric. Our o‐PN has shown a high Curie Temperature of 570 °C, while Curie Temperature of BT has been measured to be 124 °C.…”

“…Here, we will review selectively reflection, absorption, and transmission for different polymer‐solid composites in frequency ranges 700 MHz to 3 GHz (a major part of UHF range), and following SHF ranges: 8–12 GHz, 12–18 GHz, 18–26 GHz, and 26–40 GHz as a follow‐up of our review in the conference ICNP 2017 Rio, vide Acknowledgement section, of our published and on‐going work and others’ work. Present work is in the microwave part of EM waves (Table ).…”

“…Electromagnetic Interference (EMI) shielding efficiency (SE) is highest for suitable metal sheets. But to make the shield flexible and light, the world is innovating polymer composites as the 2nd generation group of EMI shielding materials . Moreover, polymers including plastics have now reduced the dominating role of metals and alloys in the world of practical materials.…”