Search

Advances in nanotechnology have opened new doors to overcome the problems related to contaminated water by introducing photocatalytic nanomaterials. These materials can effectively degrade toxic contaminants, such as dyes and other organic pollutants, into harmless by-products such as carbon dioxide and water. Consequently, these photocatalytic nanomaterials have the potential to provide low-cost and environment-friendly alternatives to conventional water and wastewater treatment techniques. In this study, a nanocomposite of zinc oxide and graphene oxide was developed and evaluated for photocatalysis. This nanocomposite was characterized by XRD, FTIR, FESEM, Diffuse Reflectance Spectroscopy (DRS), TEM and UV-Vis spectrophotometer. The photocatalytic behavior of the nanocomposite was studied through the degradation of methyl orange under ultraviolet light. It is reported that the weight ratios of zinc oxide and graphene oxide do not considerably affect the photocatalytic performance, which gives this process more compositional flexibility. Moreover, hydrogen peroxide was used as an electron scavenger to increase the time-efficiency of the process. The photodegradation rate can be significantly improved (up to 24 times) with the addition of hydrogen peroxide, which increases the number of trapped electrons and generates more oxidizing species, consequently increasing the reaction rate.

In this research, polypropylene (PP)–graphite composites were prepared using the melt mixing technique in a twin-screw extruder. Graphite, multi-walled carbon nanotubes (MWCNT), carbon black (CB), and expanded graphite (EG) were added to the PP in binary, ternary, and quaternary formations. The graphite was used as a primary filler, and MWCNT, CB, and EG were added to the PP–graphite composites as secondary fillers at different compositions. The secondary filler compositions were considered the control input factors of the optimization study. A full factorial design of the L-27 Orthogonal Array (OA) was used as a Design of Experiment (DOE). The through-plane electrical conductivity and flexural strength were considered the output responses. The experimental data were interpreted via Analysis of Variance (ANOVA) to evaluate the significance of each secondary filler. Furthermore, statistical modeling was performed using response surface methodology (RSM) to predict the properties of the composites as a function of filler composition. The empirical model for the filler formulation demonstrated an average accuracy of 83.9% and 93.4% for predicting the values of electrical conductivity and flexural strength, respectively. This comprehensive experimental study offers potential guidelines for producing electrically conductive thermoplastic composites for the manufacturing of bipolar fuel cell plates. [ABSTRACT FROM AUTHOR]

In this study, the continuous fiber rowing of 12K carbon was electrolytically oxidized by incorporating three different types of electrolytes: Ammonium bicarbonate, Sulfuric acid, and Sodium hydroxide at various concentrations. Upon chemical treatment, the fibers were grafted with 3-Aminopropyl-triethoxysilane (APTS), a silane coupling agent, to achieve better interlocking and compatibility with the thermoplastic polyurethane (TPU) matrix. Mechanical properties were analyzed by tensile tests, morphological analysis was carried out through Scanning Electron Microscopy, and spectral analysis was studied through X-ray photoelectron spectroscopy (XPS) characterizations. The results show that 10% sulfuric acid treatment plus APTS grafted carbon fiber/TPU composites showed an average tensile load capacity of 2528 N, about 39% higher than raw carbon/TPU. The morphological analysis provided compelling evidence for the increase in mechanical properties of modified fiber composites as the interfacial bonding between the electrolytically modified and silane coated fiber/TPU composites was much better than the raw fiber/TPU composites. Further, XPS results confirm that the atomic percentages of Carbon have been reduced, whereas the percentage of oxygen and nitrogen have increased. These compositional changes indicate that the overall interaction between the fiber and the matrix has been enhanced, accounting for improved compatibility between the two interacting phases. [ABSTRACT FROM AUTHOR]

Despite being inexpensive and robust, steel cord reinforcements are often prone to pose risks to user health and safety in some industrial applications such as escalator handrails and rubber conveyor belts. Steel cords can reduce the overall stability and performance of the application over time due to their inherent creep accompanied by cyclic thermal expansion and contraction. In this context, this research focuses on replacing steel cords in some critical thermoplastic polyurethane (TPU) composite applications with continuous sustainable alternate synthetic fibers that possess high specific strength (e.g. carbon, glass, and Kevlar fibers). The first part of this research characterizes the effect of epoxy coating on synthetic fibers alone by studying their mechanical properties before and after modification, whereas the second half of the research involves reinforcing a TPU matrix with raw and epoxy-coated synthetic fibers to fabricate fiber-reinforced composites by compression molding. The effect of the curing temperature of epoxy on the end performance of the manufactured specimen was also tested. An in-depth analysis of mechanical and morphological studies showed that, at almost the same volume fraction of fibers, the TPU reinforced composites with modified carbon fibers showed higher load-bearing capacities than steel cord-based analogs. Conversely, a wide variety of other relevant industrial and commercial applications can potentially draw significant benefits by implementing these modified carbon/TPU composites instead of steel cords. [ABSTRACT FROM AUTHOR]

Summary: In this research study, electrically conductive Polypropylene (PP) based composites were developed using twin‐screw extrusion technique with the objective of investigating the effects of primary and binary fillers on the overall electrical performance of the composites with relation to their mechanical properties. Thermoplastic polymers are suitable for a wide variety of applications due to their inherent characteristics, such as low density, ease of processibility, and recyclability. The addition of conductive fillers to thermoplastic resins reduces the material's resistivity and provides the ability to conduct heat and electricity, making them an excellent candidate for the manufacturing of fuel cell bipolar plates. The first part of this research study consists of studying the effect of graphite content on the electrical and mechanical properties of PP composites, whereas the second part focuses on the analysis of the effects of a multi‐filler composite system consisting of Multi‐Walled Carbon Nanotubes (MWCNT) and Carbon Black (CB) in the graphite‐PP composites. The experimental results revealed that the maximum electrical conductivity obtained from the binary filler composites is up to 127% higher compared to that of the single filler composites. The addition of binary fillers also improved the flexural strength of the composites. This experimental study constitutes new prospects in the development of electrically conductive thermoplastic composites with sound mechanical properties for fuel cell bipolar plates. [ABSTRACT FROM AUTHOR]

In this study, the polymeric nanofibers of polyvinylpyrrolidone (PVP) were manufactured using the electrospinning technique. The electrospinning process parameters such as voltage, polymer concentration, rotational speed of the collecting drum, collecting distance, and flow rate were optimized to obtain the minimum fiber diameter for sound absorption applications. The effects of these parameters on the fiber diameter as output responses were investigated by analysis of variance (ANOVA) and Taguchi's array design. Furthermore, a mathematical model was generated using response surface methodology (RSM) to model the electrospinning process. The high voltage and polymer concentration were observed to be the most significant parameters at 95% and 99% confidence level. The average model accuracy of 83.4% was observed for the predictive model of electrospinning which is considered acceptable as it is composed of complete experimental trials of 27 out of 243 runs. The experimental study offers a promising attempt in the open literature to carefully understand the effect of various electrospinning parameters when producing PVP nanofibers. [ABSTRACT FROM AUTHOR]

Self‐reinforced polyester composites (SRPCs) with light weight, high mechanical properties, good interfacial bonding, and easy to recycle at the end after use have been developed to replace traditional synthetic fiber‐reinforced plastics. This study is on fabrication of SRPCs is performed using polyethylene terephthalate (PET) as matrix and polybutylene terephthalate (PBT) as reinforcement material through compression molding via film stacking method. The compression molding parameters such as temperature, pressure, and dwell time were optimized by Taguchi method, and these values are 225°C, 8 MPa, 5 min for tensile strength, 225°C, 5 MPa, 15 min for flexural, and 215°C, 3 MPa, 5 min for impact test. Flame retardancy in SRPCs has also been introduced as a new idea to minimize the flammability nature and is helpful in engineering applications. Flame retardants (FRs) such as ammonium polyphosphate (APP), zinc borate (Zb), and magnesium hydroxide (Mg(OH)2) were used. The flame retardancy mechanism of optimized SRPCs works effectively which was evident by horizontal burning and LOI test. Thermogravimetric analysis (TGA) was also studied to confirm the thermal properties of the composites. Mechanical properties were reasonably affected by the FRs as confirmed by field emission scanning electron microscope (FESEM). [ABSTRACT FROM AUTHOR]

There has been a considerable amount of research in the development of sustainable water treatment techniques capable of improving the quality of water. Unavailability of drinkable water is a crucial issue especially in regions where conventional drinking water treatment systems fail to eradicate aquatic pathogens, toxic metal ions and industrial waste. The research and development in this area have given rise to a new class of processes called advanced oxidation processes, particularly in the form of heterogeneous photocatalysis, which converts photon energy into chemical energy. Advances in nanotechnology have improved the ability to develop and specifically tailor the properties of photocatalytic materials used in this area. This paper discusses many of those photocatalytic nanomaterials, both metal-based and metal-free, which have been studied for water and waste water purification and treatment in recent years. It also discusses the design and performance of the recently studied photocatalytic reactors, along with the recent advancements in the visible-light photocatalysis. Additionally, the effects of the fundamental parameters such as temperature, pH, catalyst-loading and reaction time have also been reviewed. Moreover, different techniques that can increase the photocatalytic efficiency as well as recyclability have been systematically presented, followed by a discussion on the photocatalytic treatment of actual wastewater samples and the future challenges associated with it. [ABSTRACT FROM AUTHOR]