Rajendra Kumar Goyal

Bio: Rajendra Kumar Goyal is an academic researcher from Malaviya National Institute of Technology, Jaipur. The author has contributed to research in topics: Peek & Nanocomposite. The author has an hindex of 20, co-authored 71 publications receiving 1236 citations. Previous affiliations of Rajendra Kumar Goyal include College of Engineering, Pune & Government of India.

Dielectric, mechanical and thermal properties of polymer/BaTiO3 composites for embedded capacitor

Abstract: Barium titanate (BaTiO3) filled polymethylmethacrylate (PMMA) composites were prepared using the simple solution method followed by hot pressing The content of BaTiO3 was varied from 0 to 65 vol% Scanning electron microscopy showed good dispersion and adhesion of BaTiO3 with the PMMA matrix The dielectric constant of the composites increased significantly There was weak dispersion in the dielectric constant of the composites (up to 45 vol%) with frequency between 100 Hz and 15 MHz The dissipation factor of the composites increased from 0021 for pure PMMA to 0029 for 45 vol% composites However, 65 vol% composite showed dispersion in dielectric constant with increasing frequency and higher dissipation factor The Lichtenecker equation agreed well with the experimental data The microhardness and the glass transition temperature of the composites increased approximately 47-fold and 42 °C, respectively, compared to pure PMMA The CTE of the 65 vol% composite is close to that of copper

Microhardness of PEEK/ceramic micro- and nanocomposites: Correlation with Halpin–Tsai model

Abstract: Microhardness of high performance PEEK matrix composites reinforced with micro- and nanosize ceramic particles of aluminum nitride and alumina was evaluated with Vickers hardness tester. The microhardness of composites increases with increasing ceramic particle loading. The microhardness of PEEK/AlN composites is higher than that of PEEK/Al2O3 composites. For a given volume fraction, the improvement in microhardness of nanocomposites is higher than that of microcomposites. For the first time, the Halpin–Tsai equation was applied to correlate the microhardness. It was found that the adjustable parameter, i.e. ξ, is different for both particles. The value of ξ is higher for nanocomposites compared to microcomposites.

Effect of aluminum nitride on thermomechanical properties of high performance PEEK

Abstract: High performance polymer matrix composites based on poly(ether–ether–ketone) (PEEK) as matrix and aluminum nitride particle (AlNp) as filler were prepared. The effect of AlNp on the storage modulus, loss modulus, mechanical loss factor, and glass transition were investigated. The AlNp reinforcement is more pronounced above glass transition temperature (Tg). Composite containing 70 wt.% AlNp exhibit about 100% increase in storage modulus at 50 °C and about 500% increase at 250 °C, and 19 °C increase in glass transition temperature as compared to pure PEEK. Peak height of tan δ for composites was decreased to one sixth of the pure PEEK. It is probably due to improved crystallinity of PEEK and strong interaction between the AlNp and PEEK matrix. SEM reveals excellent distribution of AlNp in PEEK matrix and good interaction between AlNp and PEEK matrix.

Recent Progress on Ferroelectric Polymer-Based Nanocomposites for High Energy Density Capacitors: Synthesis, Dielectric Properties, and Future Aspects.

Abstract: Dielectric polymer nanocomposites are rapidly emerging as novel materials for a number of advanced engineering applications. In this Review, we present a comprehensive review of the use of ferroelectric polymers, especially PVDF and PVDF-based copolymers/blends as potential components in dielectric nanocomposite materials for high energy density capacitor applications. Various parameters like dielectric constant, dielectric loss, breakdown strength, energy density, and flexibility of the polymer nanocomposites have been thoroughly investigated. Fillers with different shapes have been found to cause significant variation in the physical and electrical properties. Generally, one-dimensional and two-dimensional nanofillers with large aspect ratios provide enhanced flexibility versus zero-dimensional fillers. Surface modification of nanomaterials as well as polymers adds flavor to the dielectric properties of the resulting nanocomposites. Nowadays, three-phase nanocomposites with either combination of fillers...

Polymer-Nanoparticle Composites: From Synthesis to Modern Applications

Abstract: The addition of inorganic spherical nanoparticles to polymers allows the modification of the polymers physical properties as well as the implementation of new features in the polymer matrix. This review article covers considerations on special features of inorganic nanoparticles, the most important synthesis methods for ceramic nanoparticles and nanocomposites, nanoparticle surface modification, and composite formation, including drawbacks. Classical nanocomposite properties, as thermomechanical, dielectric, conductive, magnetic, as well as optical properties, will be summarized. Finally, typical existing and potential applications will be shown with the focus on new and innovative applications, like in energy storage systems.

Recent advances in electromagnetic interference shielding properties of metal and carbon filler reinforced flexible polymer composites: A review

Abstract: The rapid proliferation and elevated usage of electronic devices have led to a meteoritic rise in electronic pollutions such as electronic noise, electromagnetic interference (EMI) and radiofrequency interference (RFI) which leads to improper functioning of electronic devices. Metals and their alloys can serve as the best EMI shielding materials but their heavy weight, high cost and low corrosion resistance have limited their applications in EMI shielding. The emergence of flexible polymer composites have substituted the metal and metal alloy based EMI shielding materials due to their unique features such as light weight, excellent corrosion resistance, superior electrical, dielectric, thermal, mechanical and magnetic properties that are highly useful for suppressing the electromagnetic noises. In this review article, the EMI shielding effectiveness of flexible polymer composites comprising of metals and various forms of carbon nanofillers such as carbon black, carbon nanofibers, carbon nanotubes, graphite, graphene, graphene oxide, graphene nanosheets, graphene nanoribbons and graphene nanoplatelets have been deeply reviewed.