http://starc.stthomas.ac.in:8080/xmlui/xmlui/handle/123456789/262 2026-04-20T13:52:39Z 2026-04-20T13:52:39Z Savitha Unnikrishnan K Sunil Jose T http://starc.stthomas.ac.in:8080/xmlui/xmlui/handle/123456789/329 2024-02-23T05:57:18Z 2022-04-01T00:00:00Z

Bismaleimide nanocomposites for high dielectric applications Savitha Unnikrishnan K; Sunil Jose T High dielectric permittivity materials have widespread applications in various fields like energy storage capacitors, micro capacitors in IC, sensors, printed circuit boards etc. The introduction of high dielectric permittivity materials on the nanoscale into the polymer matrix could increase the dielectric constant of the polymer nanocomposites. For high dielectric applications, the polymer composite should exhibit high dielectric permittivity, low dielectric loss and high breakdown strength. High dielectric permittivity is highly desired for the dielectric materials used in the embedded capacitors and energy storage devices. In order to enhance the dielectric properties of the BMI-epoxy composites, suitable fillers with high dielectric constants are added. The specific objectives of the research work include • To develop a new polymer nanocomposite as a substitute for ceramic insulators with enhanced electrical and mechanical properties for high dielectric applications. • Synthesis of BaTiO3 by hydrothermal method and surface hydroxylated BaTiO3 by using H2O2 and their characterisation using SEM, EDAX and FTIR. • Fabrication of nanocomposite with bismaleimide-epoxy as polymer matrix and BaTiO3, Rochelle salt and surface hydroxylated BaTiO3 as nanofillers for improving the dielectric properties. • BMI-epoxy nanocomposite reinforced with E glass fiber (EGF) and silane-coated E glass fiber (SC-EGF) fabrication as per ASTM standards for different compositions of nanofillers. • Morphological study of the synthesised reinforced and non-reinforced composite using SEM and structural analysis using XRD, EDAX and FTIR. • Evaluation of the effect of different nanofillers and the reinforcement (EGF and SC-EGF) on thermal stability and mechanical properties such as tensile strength and flexural strength. • Studies on dielectric constant, dielectric loss factor (tan delta) and dielectric breakdown strength of the synthesised composite. • Analysis of dielectric behaviour, ac conductivity and electromagnetic interference shielding effectiveness (EMI-SE) of the fabricated BMI-epoxy nanocomposites with optimised weight percentages of the nanofiller. • Effect of MWCNT on thermo-mechanical, electrical and EMI-SE of BMI-epoxy composites with different nanofillers such as BT, RS and BTOH. • To study the suitability of the synthesised BMI-epoxy nanocomposites in relevant fields. In the present work, a new class of BMI-epoxy composites separately reinforced with E glass fiber and silane coated E glass fiber were fabricated using a simple hand layup method followed by compression moulding. Further performance enhancements made by the incorporation of a variety of nanofillers such as BaTiO3, Rochelle salt crystals and surface hydroxylated BaTiO3 nanoparticles were studied. In order to improve the ac conductivity and EMI-SE, MWCNT conductive filler is added and further investigation is carried out.

2022-04-01T00:00:00Z Anju Rose Puthukkara P Sunil Jose T http://starc.stthomas.ac.in:8080/xmlui/xmlui/handle/123456789/328 2024-03-13T05:11:14Z 2022-03-01T00:00:00Z

Modified iron-based nanoparticles for the removal of dyes and hexavalent chromium from water Anju Rose Puthukkara P; Sunil Jose T Industrialisation and urbanisation led to the contamination of groundwater and surface water to a large extent. Zero valent iron nanoparticle (Fe0 ) is a promising material for water contaminants remediation due to its large surface area to volume ratio coupled with greater reactivity. However, the Fe0 rapidly reacts with air and water and results in reduced reactivity due to oxidation and agglomeration. Our work aims to prepare modified iron-based nanoparticles with improved reactivity, stability and dispersibility without much secondary pollution. The reactivity of modified iron-based nanoparticles was evaluated by measuring the removal efficiency of hexavalent chromium and malachite green dye from water. Iron nanoparticle modification was done by depositing catalytic metal to the Fe0 surface, encapsulating it with polymer and depositing Fe0 on solid support. Green synthesis of Fe nanoparticles was done using plant extracts, which neither requires additional energy nor produces any hazardous by-products. The specific objectives of our work include (1) synthesise Fe0 and bimetallic Fe based nanoparticles using the chemical reduction method, (2) prepare chitosan stabilised Fe0 and Fe/Ni nanoparticles, (3) develop zeolite and TiO2 based novel composites as supporting and stabilising material for Fe0 nanoparticles, (4) prepare Fe nanoparticles using plant extracts as green reducing agents, (5) evaluate the efficiency of synthesised nanoparticles in the removal of toxic hexavalent chromium and toxic dyes under different reaction conditions such as initial pollutant concentration, nanoparticle dosage, contact time and solution pH. The synthesis of modified iron nanoparticles was carried out under an inert atmosphere and the collected samples were lyophilised. The characterisation of prepared nanoparticles was performed using UV-visible spectroscopy, HRTEM, EDAX, FTIR, XRD and XPS. UV-visible spectroscopy was used to analyse the remaining concentration of the pollutant after treating with Cr(VI) and toxic dyes. The degradation product of malachite green was analysed by LC-MS/MS and GC-MS/MS. The various modifications done on iron nanoparticles in our study improved the reactivity and stability of the iron nanoparticles.

2022-03-01T00:00:00Z Dinoop Lal S Sunil Jose T http://starc.stthomas.ac.in:8080/xmlui/xmlui/handle/123456789/263 2024-03-13T04:55:48Z 2020-12-01T00:00:00Z

Photodegradation of polystyrene by nano titanium dioxide and photosensitizers Dinoop Lal S; Sunil Jose T

2020-12-01T00:00:00Z