Biodoped Ceramics: Synthesis, Properties, and Applications

This feature article focuses on biodoped ceramics. These are inorganic materials in which biological materials are incorporated, thus adding new functionality to them. A brief overview of the prominent synthesis techniques for biodoped ceramics, with emphasis on modified sol–gel processes for metal oxide matrices, is given first. Theoretical treatments of the encapsulation of biologicals within a porous ceramic matrix are reviewed. Experimental studies of the stability and dynamics of protein entrapment in silica and other ceramic matrices are also discussed. Finally, key applications of biodoped ceramics in biochemical species detection, bio-catalysis, and drug delivery are presented.     

C5: A Step Towards Smart World with Enhanced Holistic Wellbeing

Wireless Personal Communications - Internet of things (IoTs) has been the smartest technology proven worldwide these days. The application products of IoTs are Mobile ad hoc network (MANET) and...     

Acrylic-ester-polyol based novel two-component polyurethane clear coat: Evaluation of performance characteristics

In the current study, a combination of acrylic polyol (AP) and ester polyol (EP) were synthesized and reacted at variable ratios with hexamethylene diisocyanates and isophorone diisocyanates to prepare a transparent two-component polyurethane (PU) coating formulation. The formations of the polyol system, isocyanate system, and the PU systems were confirmed by ¹H nuclear magnetic resonance and Fourier-transform infrared spectroscopy. Transparency of the coatings was examined using haze, and gloss measurement, which showed acrylic-ester-polyurethane (aePU-5 and aePU-6) have 91.5% and 91.8% transparency and gloss of 90.3 and 90.7 GU respectively. The thermal properties like T_g and the thermal stability of the coatings were verified using differential scanning calorimetry, and thermogravimetric analysis respectively which was found to increase with increasing EP content and decreasing AP content which may be ascribed to improved compatibility of copolymers, and homogeneity in PU along with enhanced crosslinking density. The degree of adhesion of coating with the substrate was validated from lap-shear, and cross-cut tape test which showed improved performance at AP:EP ratio of 60:40. The coatings were found to exhibit resistance toward pencil hardness with aePU-5 and aePU-6 having the optimum resistance of 9H. The surface morphology and topography were observed under scanning electron microscopy, and atomic force microscopy, respectively. The outcome confirms the higher smoothness of the surfaces subjected to the increase in EP content. The PU system with 40 wt% AP content and 60 wt% EP designated as aePU-5 was found to exhibit optimum performance.     

Conductivity and atmospheric aging studies of polypyrrole-coated cotton fabrics

Polypyrrole (PPy) is one of the preferred alternatives among the intrinsically conductive polymers (ICPs). In this study, PPy-coated cotton (PPy-CT) fabrics were synthesized by two step in situ chemical polymerization. The reaction parameters, such as monomer concentration and temperature, were studied in detail. The surface resistivity of PPy-CT fabrics ranged ∼ 15–5000 Ω⁻². To assess long-term usage potential, the atmospheric aging of conductivity characteristics of treated fabrics was monitored over a period of 6 months. It was found that the synthesis temperature had a significant impact on conductivity and atmospheric aging of PPy-CT fabrics. Furthermore, various sulfonic acid sodium salts added as external doping agents during polymerization also had a positive effect. The scanning electron microscopy revealed smoother morphology of sulfonic acid salt doped PPy coatings. The overall study addresses the durability aspect of PPy-CT fabrics in potential applications areas. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of Nanoclay on the Mechanical,Thermal, and Water Absorption Properties of an UP-toughened Epoxy Network

Unsaturated polyester (UP)-toughened epoxy nanocomposites were prepared, and their effective mechanical and thermal properties were studied. Two types of organo-modified montmorillonite (OMMT) clays were used to prepare the nanocomposites. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis showed the formation of exfoliated silicate layers in the UP-toughened epoxy matrix. Mechanical tests revealed that nanocomposites (containing 1 wt% OMMT clay) showed an increase in tensile strength to 13.8%, flexural strength to 10%, and impact strength to 4% compared with an UP-toughened epoxy blend. The effect of different heating rates on the curing behavior of UP-toughened epoxy nanocomposites was investigated using non-isothermal differential scanning calorimetry. The data were interpreted using the Kissinger and Flynn–Wall–Ozawa models to find the curing reaction parameter. The water uptake behavior for nanocomposites increased with the addition of OMMTs. Scanning electron microscopy micrographs indicated morphological changes in the impact fractured samples of UP-toughened epoxy nanocomposites.     

Effect of SO<Subscript>4</Subscript> <Superscript>2-</Superscript>, Cl<Superscript>–</Superscript> and NO<Subscript>3</Subscript> <Superscript>-</Superscript> anions on the formation of iron oxide nanoparticles via microwave synthesis

In the present work iron oxide nanoparticles have been prepared by microwave assisted synthesis with the influence of different precursor salts and synthesis of magnetite, hematite, Iron oxide hydroxide and maghemite nanoparticles. Synthesized iron oxide nanoparticles were characterized with Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), and Energy-dispersive X-ray Spectroscopy (EDX). XRD measurements show that the peaks of diffractogram are in agreement with the theoretical data of magnetite, hematite, FeO(OH) (Iron oxide hydroxide) and maghemite. Crystallite size of the particles was found to be 33, 45, 36 and 43.5 nm for Fe₃O₄, α-Fe₂O₃, FeO(OH) and γ-Fe₂O₃. FESEM studies indicated that size of the particles is observed in the range of about 19.4 to 46.7 nm (Fig. 2a, average 32 nm), 29.1 to 67.6 nm (Fig. 2b average 45 nm), 29.1 to 40.8 (Fig. 2c average 36.6 nm), 29.1 to 80 nm (Fig. 2d average 43.5) for Fe₃O₄, α-Fe₂O₃, FeO(OH) and γ-Fe₂O₃ respectively. EDX spectral analysis reveals the presence of carbon, oxygen, iron in the synthesized nanoparticles. The FTIR graphs indicated absorption bands due to O–H stretching, C–O bending, C–H stretching and Fe–O stretching vibrations.     

Electrochemical inspection of polypyrrole/chitosan/zinc oxide hybrid composites

Polymer nanocomposite composed of polypyrrole, chitosan, and zinc oxide nanoparticles has been synthesized and it has been evaluated for various electrochemical aspects of the current electrochemical industry. The polypyrrole (PPy) was synthesized by the chemical oxidative polymerization reaction by employing ammonium persulfate as oxidizing agent. Composites of polypyrrole/chitosan (PPy/Chy) and polypyrrole/chitosan/ZnO (PCZ) composites were synthesized by the solution blending method. Detailed structural, morphological, thermal characterization of PPy, PPy/Chy, and PCZ were performed to characterize the specific features of the systems. The composites exhibit better thermal stability and high surface area and the addition of ZnO nanoparticle increase the crystallinity of the composite. Electrochemical characterization of the ITO electrodes modified with PPy, PPy/Chy, and PCZ were performed using cyclic voltammetry, electrochemical impedance spectroscopy, and amperometry techniques. The present study highlights the role of a bio-compatible material with high surface area and conductive constituent for designing of various high performing electronic noninvasive sensors, biosensors, and so forth.     

Composition and Recyclability Analysis of Poly(Vinyl Chloride) Recovered from Computer Power Cables and Commercial Wires

The product‐based recycling of the electrical and electronic devices and their by‐products are limited due to their complex characteristics and dissimilar material characteristics. However, such recycling procedures give clear ideas about the composition and possible recycling options of the materials present in them. Consequently, the present study deals with isolation and recycling of the major polymeric fraction present in the waste computer power supply cables (CPS) and electrical power supply (EPS) wires isolated from the household items. The composition analysis of CPS and EPS indicates that the poly(vinyl chloride) (PVC) is the major polymeric fraction along with minor content of polyethylene (PE) and polycarbonate (PC). Further, this research compares the mechanical recyclability of the PVC recovered from the CPS and EPS. Among the PVC's analyzed, PVC isolated from the EPS has been indicated superior mechanical properties. Similarly, thermal degradation analysis (TGA) indicated higher thermal stability for the PVC isolated from EPS. Besides, the flammability of the PVC specimens was studied and concluded with the possible mechanism occurring during combustion. Moreover, this study points out that PVC recovered from EPS and CPS can be mechanically recycled for the elimination of the waste. J. VINYL ADDIT. TECHNOL., 26:213–223, 2020. © 2019 Society of Plastics Engineers     

Influence of organically modified nanoclay on the performance of pineapple leaf fiber‐reinforced polypropylene nanocomposites

Polypropylene/Pine apple leaf fiber (PP/PALF)‐reinforced nanocomposites were fabricated using melt blending technique in a twin‐screw extruder (Haake Rheocord 9000). Variation in mechanical properties, crystallization behavior, water absorption, and thermal stability with the addition of nanoclay in PP/PALF composites were investigated. It was observed that the tensile, flexural, and impact properties of PP increase with the increase in fiber loading from 10 to 30 wt %. Composites prepared using 30 wt % PALF and 5 wt % MA‐g‐PP exhibited optimum mechanical performance with an increase in tensile strength to 31%, flexural strength to 45% when compared with virgin PP. Addition of nanoclay results in a further increase in tensile and flexural strength of PP/PALF composites to 20 and 24.3%, which shows intercalated morphology. However, addition of nanoclay does not show any substantial increase in impact strength when compared with PP/PALF composites. Dynamic mechanical analysis tests revealed an increase in storage modulus (E′) and damping factor (tan δ), confirming a strong influence between the fiber/nanoclay and MA‐g‐PP. Differential scanning calorimetry, thermogravimetric analysis thermograms also showed improved thermal properties when compared with the virgin matrix. TEM micrographs also showed few layers of agglomerated clay galleries along with mixed nanomorphology in the nanocomposites. Wide angle X‐ray diffraction studies indicated an increase in d‐spacing from 22.4 Å in Cloisite 20A to 40.1 Å in PP/PALF nanocomposite because of improved intercalated morphology. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009