Vinay Panwar

Antibacterial Properties of Silver Doped TiO2 Nanoparticles Synthesized via Sol-Gel Technique

In this work, antibacterial, micro-structural, and fluorescence properties of silver (Ag) doped TiO2 nanoparticles were studied to analyze the effect of silver for effective improvement in antibacterial properties of TiO2. Antibacterial properties of pure TiO2 and Ag-TiO2 was studied using Escherichia coli, Pseudomonas aeruginosa as Gram Negative and Bacillus subtilis, Staphylococcus aureus as Gram positive bacteria, as a model for Agar disc diffusion assay method. The concept of inhibition zone diameter was applied to observe the antibacterial activity of TiO2 and Ag-TiO2. It was observed that the antibacterial activity of TiO2 improves with doping of Ag. Fluorescence spectra confirm the red shift in band edge emission at excitation wavelength of 360 nm which shows effective fluorescence properties of these nanoparticles. Microstructures of these nanoparticles have studied with the help of transmission electron microscopy (TEM) and atomic force microscopy (AFM).

Graphene oxide–polyaniline–polypyrrole nanocomposite for a supercapacitor electrode

Graphene oxide based nanocomposites were prepared through the in situ polymerization of aniline and pyrrole to study the interaction of graphene oxide with polyaniline (PANI) and polypyrrole (PPy). Field emission scanning electron microscopy (FESEM) was used to study the surface morphology and transmission electron microscopy (TEM) for the qualitative understanding of the internal structure of PANI/PPy coating on GO. The chemical structures of composites were studied through X-ray photoelectron spectroscopy (XPS) analysis. It was observed that specific capacitance of PPy coated GO improved by ∼122.73% compared to pristine GO. Moreover, the binding energy of polypyrrole–graphene oxide was found to be higher than polyaniline–graphene oxide because of the absence of oxygen containing functional groups. In addition, the storage capacity was effectively improved due to the synergistic effect of polypyrrole coating on graphene oxide.

Effective energy harvesting from a single electrode based triboelectric nanogenerator

The arch-shaped single electrode based triboelectric nanogenerator (TENG) is fabricated using thin film of reduced graphene oxide nanoribbons (rGONRs) with polyvinylidene fluoride (PVDF) polymer used as binder to effectively convert mechanical energy into electrical energy. The incorporation of rGONRs in PVDF polymer enhances average surface roughness of rGONRs/PVDF thin film. With the combination of the enhancement of average roughness and production of functional groups, which indicate improve charge storage capacity of prepared film. Furthermore, the redox peaks obtained through cyclic voltammetry were identified more in rGONRs/PVDF composite in comparison to pristine rGONRs to confirm charge transfer capability of film. Herein, the output performance was discussed experimentally as well as theoretically, maximum voltage was obtained to be 0.35 V. The newly designed TENG to harvest mechanical energy and opens up many new avenues of research in the energy harvesting applications.

An Investigation on Vibration Welding of Amorphous and Semicrystalline Polymers

Vibration welding technique has been used to study the weld zone of thermoplastic polymers using ABS (amorphous), PC (amorphous), PMMA (amorphous), and PBT (semicrystalline). Polymers were welded using alike components and combinations of semicrystalline polymer with different amorphous polymers. Mechanical testing of welded polymers has proved that the tensile strength, elongation at break, and deformation was highest for PC–PC weld and least for ABS–ABS weld, when alike polymers were welded. However, welding of semicrystalline and amorphous polymer shows enormous reduction in its tensile strength as well as other tensile properties. Also, the tensile fracture of PBT with other amorphous polymers always occurred at weld zone which was not always in case of alike polymer welds. The weld strength of these polymers was observed to be dependent on the mechanical interlocking among the layers and not on interfacial bonding. This phenomenon may be due to the difference in glass transition temperatures of semicrystalline and amorphous polymers. XRD, FESEM, and AFM have been used in this study to observe the morphology of welded surfaces.

Effect of nanoclay on carbon black reinforced blend of amorphous–semicrystalline polymers

In this work, the effect of nanoclay in carbon black reinforced PC-PBT has been investigated on the basis of changes in their mechanical and thermal properties. It has been believed on the basis of FESEM images that CB supports for the expansion of PBT rods and PC wraps around these expanded rods. However, the effect of reinforcing filler for improvement in mechanical properties has been found insignificant which may be due to the agglomeration of reinforcing particles. Addition of nanoclay in carbon black reinforced PC-PBT composite blend shown considerable improvement in its tensile strength (113%). This should be due to the improved dispersion of CB in polymer matrix and better linked-up structure of PBT rods after addition of NC. In addition, this combination has shown simultaneous improvement in tensile strength and ductility which is unusual and may be desirable in many structural applications.

Thermomechanical behaviour of zirconia–multiwalled carbon nanotube-reinforced polypropylene hybrid composites

The present investigation reveals the effect of addition of zirconia-coated multiwalled carbon nanotubes (MWCNTs) on mechanical and thermal properties of polypropylene (PP) matrix composites. Initially, zirconia coating on MWCNTs (ZrO2–CNT) has been performed with the help of isothermal hydroxylation technique and confirmed through typical microstructural and morphological characterizations. Thereafter, the effect of zirconia of mechanical and thermal properties of PP matrix composites has been studied through comparing the thermal decomposition behaviour, tensile and thermomechanical properties of pure PP, MWCNT-reinforced PP composite and ZrO2–CNT-reinforced PP hybrid composite. In short, the addition of 5 wt% CNTs improved tensile modulus by 22%, tensile strength by 16% and storage modulus by 45%, while the addition of same amount of ZrO2–CNT improved the above sequenced properties by 44, 47 and 73%, respectively. Moreover, ZrO2–CNT/PP hybrid composite has been found to have better thermally stability than pure PP as well as CNT/PP composite.

Rubber blend nanocomposites

This chapter is intended to realize the positive aspects of blending and use of fillers in rubber matrices. Although these are very old techniques on which a lot of literature is available, some recent studies have brought out important and exciting facts through integrating both processes. The advancement towards newer nanofillers having promising multidirectional properties invites researchers to explore the effect of these materials in rubber/rubber and rubber/plastic blends. To proceed in this direction it is really important to provide a common platform which clears up the physical significance of rubber blend nanocomposites. So, in this review we have included some past and recent works to clarify the need of rubber blend nanocomposites and the requirements for their further investigation. In addition, this study provides an overview for the suitability of different rubber nanocomposites for a better product specific utilization.

Dynamic Mechanical Analysis of Clay–Polymer Nanocomposites

Thermomechanical stability of polymer nanocomposites plays a vital role in studying the molecular mobility transitions under varying temperatures. In this regard, dynamic mechanical analysis (DMA) explores the viscoelastic properties, i.e., storage modulus, loss modulus, and damping factor, of polymer-based nanocomposites. Commonly, because of the higher stiffness of fillers, storage modulus has been noticed to improve after the addition of nanofillers, while damping behavior shows reduced performance caused by restrictions in the movement of polymer chains. The main purpose of DMA in clay–polymer nanocomposites is to recognize thermodynamic interactions between its components, i.e., matrix and filler. A number of existing studies have shown that clay acts as a good compatibilizer for better dispersion of carbon-based fillers/nanofillers in polymer matrices and have reported the effectiveness of their findings with the help of thermomechanical properties of such composites. This chapter is designed to show the importance of this technique for further research related to clay-reinforced polymer blends/nanocomposites and to locate the key aspects for its precise investigation.