Mouldable Conductive Plastic with Optimised Mechanical Properties.

This paper investigates making an injection mouldable conductive plastic formulation that aims for conductivity into the electromagnetic interference (EMI) shielding range, with good mechanical properties (i.e., stiffness, strength, and impact resistance). While conductivity in the range (electrostatic charge dissipation) and EMI shielding have been attained by incorporating conductive fillers such as carbon black, metals powders, and new materials, such as carbon nanotubes (CNTs), this often occurs with a drop in tensile strength, elongation-to-break resistance, and impact resistance. It is most often the case that the incorporation of high modulus fillers leads to an increase in modulus but a drop in strength and impact resistance. In this work, we have used short carbon fibres as the conductive filler and selected a 50/50 PBT/rPET (recycled PET) for the plastic matrix. Carbon fibres are cheaper than CNTs and graphenes. The PBT/rPET has low melt viscosity and crystallises sufficiently fast during injection moulding. To improve impact resistance, a styrene-ethylene-butadiene-styrene (SEBS) rubber toughening agent was added to the plastic. The PBT/rPET had very low-impact resistance and the SEBS provided rubber toughening to it; however, the rubber caused a drop in the tensile modulus and strength. The short carbon fibre restored the modulus and strength, which reached higher value than the PBT/rPET while providing the conductivity. Scanning electron microscope pictures showed quite good bonding of the current filler (CF) to the PBT/rPET. An injection mouldable conductive plastic with high conductivity and raised modulus, strength, and impact resistance could be made.

Bismuth ferrite based acetone gas sensor: evaluation of graphene oxide loading.

We report a BiFeO3/graphene oxide (BFO/GO) perovskite, synthesized using a CTAB-functionalized glycine combustion route, as a potential material for acetone gas sensing applications. The physicochemical properties of the developed perovskite were analysed using XRD, FE-SEM, TEM, HRTEM, EDAX and XPS. The gas sensing performance was analysed for various test gases, including ethanol, acetone, propanol, ammonia, nitric acid, hydrogen sulphide and trimethylamine at a concentration of 500 ppm. Among the test gases, the developed BFO showed the best selectivity towards acetone, with a response of 61% at an operating temperature of 250 °C. All the GO-loaded BFO samples showed an improved gas sensing performance compared with pristine BFO in terms of sensitivity, the response/recovery times, the transient response curves and the stability. The 1 wt% GO-loaded BiFeO3 sensor showed the highest sensitivity of 89% towards acetone (500 ppm) at an operating temperature of 250 °C. These results show that the developed perovskites have significant potential for use in acetone gas sensing applications.

Effect of Soy Wax/Rice Bran Oil Oleogel Replacement on the Properties of Whole Wheat Cookie Dough and Cookies.

This study investigated the replacement of butter with soy wax (SW)/rice bran oil (RBO) oleogel in varied proportions in cookie dough and the resulting cookies. The study mainly evaluates the physical, textural, and chemical properties of the butter cookie dough and cookies by replacing butter with SW/RBO oleogel. The dough was assessed using moisture analysis, microscopy, FTIR Spectroscopy (Fourier Transform Infrared) and impedance spectroscopies, and texture analysis. Micrographs of the dough showed that D-50 (50% butter + 50% oleogel) had an optimal distribution of water and protein. D-0 (control sample containing 100% butter) showed the lowest impedance values. Moisture content ranged between 23% and 25%. FTIR spectroscopy suggested that D-50 exhibited a consistent distribution of water and protein, which CLSM and brightfield microscopy supported. Texture analysis revealed that the dough samples exhibited predominantly fluidic behavior. As the amount of oleogel was raised, the dough became firmer. The prepared cookies showed a brown periphery and light-colored center. Further, a corresponding increase in surface cracks was observed as the oleogel content was increased. Cookies moisture analysis revealed a range between 11 and 15%. Minute changes were observed in the texture and dimensions of the cookies. In summary, it can be concluded that replacing butter with oleogel by up to 50% seems to be feasible without significantly compromising the physicochemical properties of cookie dough and cookies.

Studies on the Effect of the Addition of Nano-Spherical Particles of Aluminum on the Thermal, Mechanical, and Morphological Properties of PBT-PET Blend Composites.

In previous works, we had found that the addition of micron-sized, irregular-shaped aluminum (Al) powder, or Al nano platelets (flakes), improved the mechanical properties of polyesters, and that, additionally, the flakes led to an increase in electrical conductivity. The aim of this work was to examine the effect of nano-spherical particles of aluminum in a 60/40 PBT/PET polyester blend. A blend was used because it can help with the formation of a segregated network of metal particles that allows electrical conductivity at low loading. The notched Izod impact of Al nano-spherical composites increased with nano Al content up to an addition level of 2 vol.%. However, the tensile strength and flexural strength decreased gradually with increasing filler loading. Thus, the spherical shape and nano size of the Al particle caused it to be less effective than the micron-sized, irregular-shaped Al powder, or the Al flakes. The reason for this is that, while nano spherical particles have high surface area for bonding with the matrix, the Al-Al aggregation stands in the way of wetting by the polymer melt, whereas aggregation in flakes does not cause as much of a problem. The segregated network structure to enhance electrical conductivity did not form in this blend system with nano spherical particles. The nano-spherical Al acted as a nucleating agent but did not cause transesterification between the two polyesters or make it more susceptible to degradation.

Evaluation of Structural, Magnetic, and Electromagnetic Properties of Co2+-Substituted NiCuZn Ferrites.

We report citrate gel-assisted autocombusted spinel-type Co2+-substituted NiCuZn ferrites and their electromagnetic properties. Several complementary techniques were used to investigate the influence of Co on structural and electromagnetic properties of Ni0.25-xCoxCu0.20Zn0.55Fe2O4 with x = 0.00-0.25 (step of 0.05). XRD analysis confirmed the highly crystalline single-phase cubic spinel structure with a prominent peak of the (311) plane. FE-SEM analysis showed the loss of porous gel structure (colloidal backbone) due to addition of cobalt into the present ferrite system. The EDAX analysis confirmed the presence of Ni, Cu, Zn, Co, and O in accordance with the relative stoichiometry of Co-substituted NiCuZn ferrite. The electrical resistivity of ferrites is observed to decrease when Co2+ ions are substituted, regardless of AC and DC. The dielectric properties (ε' and ε″) of ferrites exhibited a consistent decrease as the frequency increased, and this trend persisted even at higher frequencies. VSM analysis showed the normal magnetic hysteresis of the developed ferrite system. At x = 0.05, the saturation magnetization of the ferrite was obtained to be the highest among the other substitution levels of Co. The Curie temperature fell down when there was a higher concentration of cobalt in the ferrite system (x = 0.20). After reaching a specific temperature, the µi values decreased abruptly, with an increase in the temperature. The steady state may be deduced from the fact that the constant real component of the initial permeability, µ', remained unchanged. However, with decreasing frequency, the values of µâ€³ decreased dramatically. The present NiCuZn ferrite series displays the enhanced dielectric properties suggesting the capability of potential candidates for microwave absorption applications with enhanced electromagnetic properties.

Synergistic Effect of Nanoparticles: Enhanced Mechanical and Corrosion Protection Properties of Epoxy Coatings Incorporated with SiO2 and ZrO2.

This research paper presents the fabrication of epoxy coatings along with the hybrid combination of SiO2 and ZrO2. The epoxy resin is incorporated with SiO2 as the primary pigment and ZrO2 as the synergist pigment. The study delves into the adhesion, barrier, and anti-corrosion properties of these coatings, enriched with silica and zirconium nanoparticles, and investigates their impact on the final properties of the epoxy coating. The epoxy resin, a Diglycidyl ether bisphenol-A (DGEBA) type, is cured with a polyamidoamine adduct-based curing agent. To evaluate the protective performance of silica SiO2 and zirconia ZrO2 nanoparticles in epoxy coatings, the coated samples were tested in a 3.5% NaCl solution. The experimental results clearly demonstrate a remarkable improvement in the ultimate tensile strength (UTS), yield strength (YS), and Elastic Modulus. In comparison to using SiO2 separately, the incorporation of both ZrO2 and SiO2 resulted in a substantial increase of 43.5% in UTS, 74.2% in YS, and 8.2% in Elastic Modulus. The corrosion test results revealed that the combination of DGEBA, SiO2, and ZrO2 significantly enhanced the anti-corrosion efficiency of the organic coatings. Both these pigments exhibited superior anti-corrosion effects and mechanical properties compared to conventional epoxy coatings, leading to a substantial increase in the anti-corrosion efficiency of the developed coating. This research focuses the potential of SiO2 and ZrO2 in hybrid combination for applications, where mechanical, corrosion and higher adhesion to the substrates are of prime importance.

The Effect of Zirconia Nanoparticles on Thermal, Mechanical, and Corrosion Behavior of Nanocomposite Epoxy Coatings on Steel Substrates.

Zirconia (ZrO2) nanoparticles (1-3 wt.%) were incorporated into the epoxy matrix using the ultra-sonication mixing method of dispersion to manufacture nanocomposite coatings. An automatic applicator was used to prepare the coating samples on a stainless steel substrate. The influence of ZrO2 nanoparticles on the physicochemical characteristics of epoxy coatings was evaluated using energy dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FTIR), thermos-gravimetric analysis (TGA), elastic modulus, and micro-hardness measurement with the nano-indentation technique. The corrosion stability during immersion in 3.5% NaCl solution was monitored using electrochemical impedance spectroscopy (EIS). All ZrO2-containing coatings showed better corrosion stability and adhesion than pure epoxy coating. Epoxy coating incorporated with 2% ZrO2 exhibited the greatest values of corrosion resistance and adhesion due to the effect of nanoparticle properties and their better de-agglomeration in the epoxy matrix than pure epoxy coating.

Development of a Soft Robotic Bending Actuator Based on a Novel Sulfonated Polyvinyl Chloride-Phosphotungstic Acid Ionic Polymer-Metal Composite (IPMC) Membrane.

This work presents the development of a cost-effective electric-stimulus-responsive bending actuator based on a sulfonated polyvinyl chloride (SPVC)-phosphotungstic acid (PTA) ionic polymer-metal composite (IPMC), using a simple solution-casting method followed by chemical reduction of platinum (Pt) ions as an electrode. The characterizations of the prepared IPMC were performed using Fourier-transform infrared (FTIR) spectroscopy, Scanning electron microscopy (SEM), X-ray diffraction (XRD) techniques, Thermogravimetric analysis (TGA), and Energy-dispersive X-ray (EDX) analysis. Excellent ion-exchange capacity (IEC) and proton conductivity (PC), with values of ca. 1.98 meq·g-1 and ca. 1.6 mS·cm-1, respectively, were observed. The water uptake (WU) and water loss (WL) capacities of the IPMC membranes were measured at 25 °C, and found to have maxima of ca. 48% for 10 h, and ca. 36% at 6 V DC for almost 9 min, respectively. To analyze the actuation performance of the developed membrane, tip displacement and actuation force measurements were conducted. Tip displacement was found to be ca. 15.1 mm, whereas bending actuation was found to be 0.242 mN at 4 V DC. The moderate water loss, good proton conductivity (PC), high thermal stability, and good electrochemical properties of the developed IPMC membrane actuator position it as a cost-effective alternative to highly expensive conventional perfluorinated polymer-based actuators.

Development and Characterization of PA 450 and PA 3282 Epoxy Coatings as Anti-Corrosion Materials for Offshore Applications.

The optimization of two different types of hardeners, namely polyaminoamine adduct (Aradur 450 BD) and polyamidoamine adduct (Aradur 3282 BD), with diglycidyle ether of bisphenol-A (DGEBA) epoxy resin was carried out. Three different stoichiometries of PA 450 to the epoxy resin to fabricate E-0, E-1, and E-2 coating samples and the other three of PA 3282 to the epoxy resin to fabricate F-0, F-1, and F-2 coating samples were coated on mild steel panels. All coated samples were characterized by scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR), thermo-gravimetric analysis (TGA), and nanoindentation techniques. The electrochemical corrosion behavior of the fabricated coatings was investigated using electrochemical impedance spectroscopy (EIS) after various exposures in the climatic conditions in 3.5% NaCl solutions. It was found that the coatings possess almost identical thermal and mechanical properties. Moreover, the E-1 coating shows better corrosion resistance compared to E-0 and E-2 coatings. On the other hand, the F-1 coating was the most effective in significantly improving corrosion resistance. Overall, the addition of PA 450 and PA 3282 to some stoichiometries improves the corrosion resistance of the fabricated coatings.

A Convenient and Simple Ionic Polymer-Metal Composite (IPMC) Actuator Based on a Platinum-Coated Sulfonated Poly(ether ether ketone)-Polyaniline Composite Membrane.

Herein, we present new approaches for developing sulfonated polyether ether ketone (SPEEK) and polyaniline-based (PANI) actuator formed by film-casting and chemical reduction of Pt electrodes. We have thoroughly studied the synthesis of SPEEK and characterized it by different analytical techniques. The ion-exchange capacity (IEC) and proton conductivity of SPEEK-PANI polymer membrane were calculated to be 1.98 mmol g-1 and 1.97 × 10-3 S cm-1, respectively. To develop an IPMC actuator, SPEEK was combined with PANI through in-situ polymerization method. SEM and XRD were used to check the morphology of the given SPEEK-PANI-Pt membrane. In addition, FT-IR and EDX techniques confirmed the molecular structure and chemical conformation of SPEEK-PANI polymer membrane. Pt electrode layers homogeneously dispersed on the IPMC membrane surface, which was demonstrated by smooth SEM micrographs. The actuation functioning, including the high bending deflection, proton conductivity, current density and IEC of IPMC actuator based on SPEEK-PANI-Pt, was obtained owing to its strong electrochemical and electromechanical characteristics. Synergistic combinations of SPEEK and PANI produced membrane that are flexible, mechanically strong and robust. The developed materials have immense capability as actuators for various applications including in biomimetics and robotics.

Amorphous Poly(ethylene terephthalate) Composites with High-Aspect Ratio Aluminium Nano Platelets.

Previously, we reported that amorphous poly(ethylene terephthalate) (PET) filled with irregular nodular aluminium (Al) particles gave simultaneous increases in tensile modulus, tensile strength, and impact resistance, which is unusual for materials. Here, we investigated the effect of the particle shape and size by using nano-platelet Al. The Al nano-platelets had a thickness higher than graphenes and clays, but lower than mica and talc, and due to their large widths, they had high aspect ratios. Due to the ductility of Al, the platelets maintained the high aspect ratio and did not snap during injection moulding. In addition to avoiding the usual drop in tensile strength and impact, the composites with nano Al platelets gave an unusually high flexural modulus (8 GPa), which was almost double that attained practically with talc, mica, and graphene. This was because of the high tendency of the Al nano platelets to become oriented during moulding. The Al-PET composite would be a more cost-and-performance effective combination for making conductive composites. The Al is a cheaper material than graphene, surface treatment for adhesion (to PET) is unnecessary, and dispersion issues, such as exfoliation and de-aggregation, are not a problem.

Isolation and Characterization of Alpha and Nanocrystalline Cellulose from Date Palm (Phoenix dactylifera L.) Trunk Mesh.

Highly pure cellulosic polymers obtained from waste lignocellulose offer great potential for designing novel materials in the concept of biorefinery. In this work, alpha-cellulose and nanocrystalline cellulose were isolated from the date palm trunk mesh (DPTM) through a series of physicochemical treatments. Supercritical carbon dioxide treatment was used to remove soluble extractives, and concentrated alkali pretreatment was used to eliminate the lignin portion selectively to obtain alpha-cellulose in approximately 94% yield. Further treatments of this cellulose yielded nanocrystalline cellulose. The structure-property relationship studies were carried out by characterizing the obtained polymers by various standard methods and analytical techniques such as Fourier transform infrared spectroscopy-attenuated total reflection (FTIR-ATR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), energy dispersive X-ray diffraction (EDX-XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Almost 65% yield of pure cellulose was achieved, out of which 94% is the alpha-cellulose. This cellulose shows good thermal stability and crystallinity. The microscopic analysis of the nanocellulose showed a heterogeneous mix of irregular-shaped particles with a size range of 20-60 nm. The percentage crystallinity of alpha-cellulose and nanocellulose was found to be 68.9 and 71.8, respectively. Thus, this study shows that, this DPTM-based low-cost waste biomass can be a potential source to obtain cellulose and nano-cellulose.

Effects of SiO2 and ZnO Nanoparticles on Epoxy Coatings and Its Performance Investigation Using Thermal and Nanoindentation Technique.

Synergistic formulations were developed with nano-pigments, and their effects on the mechanical properties on steel substrates and structures were evaluated. This paper provides a complete analysis of the epoxy coating, focusing on the incorporation of nano-pigments and their synergistic effects in obtaining higher mechanical properties. This study reports the preparation of epoxy nano-silica composites, their characterization, and the development of coatings based on nano-silica and ZnO particles. In this composite, epoxy resin was incorporated with SiO2 as the main pigment and ZnO as a synergistic pigment to achieve high-performance epoxy coatings for multiple applications. The mechanical properties of these coatings (ESZ1-ESZ3) were evaluated by nanoindentation, and were used to measure the enhanced durability of nanocomposite coatings developed with synergistic formulations with different types of nanoparticles. Their performance was evaluated before and after exposure to a 3.5% NaCl solution to examine the changes of hardness and elastic modulus. The results showed that the nanoindentation technique, in conjunction with Fourier transform infrared spectroscopy and X-ray diffraction, could examine the durability and predict the service life of nanocomposite coatings. A correlation was observed between the modulus and hardness before and after exposing epoxy composite coatings (ESZ1-ESZ3) to a 3.5% NaCl solution.

Development of Hydrophobic, Anticorrosive, Nanocomposite Polymeric Coatings from Canola Oil: A Sustainable Resource.

A novel hydrophobic Canola oil-based nanocomposite anticorrosive coating material with different contents of fumes silica (FS) was successfully synthesized via an in situ method. Firstly, a Canola oil-based hydroxyl terminated poly (oxalate-amide) was prepared by a two-step process of amidation and condensation. Secondly, the dispersion of fumed silica (1 to 3 wt.%) in hydroxyl terminated poly (oxalate-amide) was carried out, followed by reaction with toluene-2,4- diisocyanate (TDI) in order to form poly (urethane-oxalate-amide)/fumed silica nanocomposite. The structure and properties of nanocomposite were analyzed by FTIR, NMR (1H/13C), TGA/DTA, DSC, contact angle, and SEM. The physico-mechanical and electrochemical tests were performed in order to check the performance of nanocomposite coating. The results reveal that FS is homogenously dispersed in poly (urethane-oxalate-amide) matrix with a loading amount of less than 3 wt.%. The performance of nanocomposite coating improved when compared to virgin polymer. The synthesized nanocomposite coating can be used in the field of hydrophobic anticorrosive coatings.

Aluminum-Filled Amorphous-PET, a Composite Showing Simultaneous Increase in Modulus and Impact Resistance.

Metal-plastic composites have the potential to combine enhanced electrical and thermal conductivity with a lower density than a pure metal. The drawback has often been brittleness and low impact resistance caused by weak adhesion between the metal filler and the plastic. Based on our observation that aluminum foil sticks very strongly to poly(ethylene terephthalate) (PET) if it is used as a backing during compression moulding, this work set out to explore PET filled with a micro and a nano aluminum (Al) powder. In line with other composites using filler particles with low aspect-ratio, the tensile modulus increased somewhat with loading. However, unlike most particle composites, the strength did not decrease and most surprisingly, the Izod impact resistance increased, and in fact more than doubled with certain compositions. Thus, the Al particles acted as a toughening agent without decreasing the modulus and strength. This would be the first case where addition of a metal powder to a plastic increased the modulus and impact resistance simultaneously. The Al particles also acted as nucleating agents but it was not sufficient to make PET crystallize as fast as the injection moulding polyester, poly(butylene terephthalate) (PBT).

Synthesis and characterization of novel tamarind gum and rice bran oil-based emulgels for the ocular delivery of antibiotics.

In this study, we developed tamarind gum (TG) and rice bran oil (RBO)-based emulgels. The control formulation (TR0), did not contain RBO. The emulgels were named as TR1, TR2, TR3, and TR4, which contained 5% (w/w), 10% (w/w), 15% (w/w), and 20% (w/w/) of RBO, respectively. The microscopic studies showed that the emulgels were biphasic in nature. FTIR spectroscopy revealed the reduction in the hydrogen bonding with an increase in the RBO content. Impedance profiles suggested that the resistive component of the emulgels was increased as the RBO content was increased. The thermal analysis suggested that the addition of RBO reduced the water holding capacity of the emulgels. Stress relaxation studies revealed that the fluidic component was considerably higher in TG/RBO-based emulgels as compared to TR0. In vitro release study of the model drug (ciprofloxacin HCl; a hydrochloride salt of ciprofloxacin) suggested a significantly lower release from the emulgel matrices (TR1-TR4) in comparison to TR0. However, ex vivo corneal permeation of the drug increased with an increase in the RBO content. Since the emulgels were able to improve the corneal permeation of the model drug, the emulgels can be explored to deliver drugs to the internal structures of the eye.

Effect of Incorporated ZnO Nanoparticles on the Corrosion Performance of SiO2 Nanoparticle-Based Mechanically Robust Epoxy Coatings.

This paper presents the studies of the development of a high-performance epoxy coating for steel substrates. To this end, it investigated the synergistic effect of incorporating zinc oxide (ZnO) nanoparticles into nanosilica containing epoxy formulations. The mechanical properties of the epoxy coating formulations were improved by modifying the surfaces of the silica nanoparticles (5 wt.%) with 3-glycidoxypropyl trimethoxysilane, which ensured their dispersal through the material. Next, the ZnO nanoparticles (1, 2, or 3 wt.%) were incorporated to improve the corrosion performance of the formulations. The anticorrosive properties of the coatings were examined by electrochemical impedance spectroscopy (EIS) of coated mild steel specimens immersed in 3.5% NaCl solution over different time intervals (1 h to 30 days). Incorporation of the ZnO nanoparticles and the nanosilica into the coating formulation improved the corrosion resistance of the epoxy coating even after long-term exposure to saline test solutions. Finally, to evaluate how the nanoparticles affected the chemical and morphological properties of the prepared coatings, the coatings were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD).

Microstructure characterization and corrosion resistance properties of Pb-Sb alloys for lead acid battery spine produced by different casting methods.

The aim of this study is to find out the microstructure, hardness, and corrosion resistance of Pb-5%Sb spine alloy. The alloy has been produced by high pressure die casting (HPDC), medium pressure die casting (AS) and low pressure die casting (GS) methods, respectively. The microstructure was characterized by using optical microscopy and scanning electron microscopy (SEM). The hardness was also reported. The corrosion resistance of the spines in 0.5M H2SO4 solution has been analyzed by measuring the weight loss, impedance spectroscopy and the potentiodynamic polarization techniques. It has been found that the spine produced by HPDC has defect-free fine grain structure resulting improvement in hardness and excellent corrosion resistance.