Preparation of a Photosensitive Composite Carbon Fiber for Spilled Oil Cleaning

This paper deals with preparing a functional composite carbon fiber with a large surface area for spilled oil cleaning. The composite fiber consisted of photosensitive oxide particles and polymer-derived carbon. It was made by co-spinning the polymer and metallic compounds. After heat treatment at high temperatures, an activated carbon fiber containing oxide particles was obtained. The particles were found distributed in the fiber and at the surface of the fiber. The composite fiber was found sensitive to sunlight. Fiber mats made of the composite fiber possessed a high surface area for oil absorption and removal. Cobalt(II) titanate particles were obtained from the reaction of titanium dioxide and cobalt oxide. The reaction happened in situ through the hydrolysis of metallic compounds in the spun fiber. The titanium dioxide and cobalt(II) titanate particle-containing fibers demonstrated the photoactivity in the visible light spectrum. It was concluded that particle-containing composite carbon fiber mats can be prepared successfully by co-electrospinning. Due to the oleophilic property and the high active surface area, the composites are suitable for spilled oil cleaning through fast absorption.

Analysis of Mechanical Behavior of Al6061 Composites Reinforced with Titanium Dioxide

Aluminum alloys are used low density good mechanical properties, better wear resistance as compared to predictable metals and their alloys. The industries are continuing in demand to develop light weight material, inexpensive and strong material which has led to the growth of aluminum alloy metal matrix composites. The aluminum based metal matrix composites have been moulded using TiO2 as reinforcement materials using the stir casting process. The hardness and tensile strength have been calculated addition to the TiO2 in Aluminium matrix improves the hardness of the material. The tensile strength and hardness increases above 4% of titanium oxide particles in the matrix.

Precipitation of Iron Oxide in Hydrogel with Superparamagnetic and Stimuli-Responsive Properties

In this work, we present a template-based preparation of iron oxide-containing hydrogels (ferrogels) with ionic sensitive and superparamagnetic properties. The influence of the cross-linked template polyacrylamide and the concentration of the iron salts and sodium hydroxide on the precipitation of the iron oxide particles is investigated with respect to the stability of the ferrogels. Scanning electron microscope images show cubic particles, which can be semiquantitatively classified in three groups of particle size with respect to the dilution level. Magnetic hysteresis curves reveal a sigmoidal shape without remanence and coercivity for all samples. The higher cross-linked ferrogels, in comparison with the lower cross-linked ferrogels, possess a steady-state degree of swelling in ultrapure water and a stimuli-sensitive deswelling over a wide range of varying ionic strengths. Thus, they are suitable candidates for applications in sensing and microfluidics.

Modeling the Effective Conductive Properties of Polymer Nanocomposites with a Random Arrangement of Graphene Oxide Particles

Сomposite materials are widely used in various industrial sectors, for example, in the aviation, marine and automotive industries, civil engineering and others. Methods based on measuring the electrical conductivity of a composite material have been actively developed to detect internal damage in polymer composite materials, such as matrix cracking, delamination, and other types of defects, which make it possible to monitor a composite’s state during its entire service life. Polymers are often used as matrices in composite materials. However, almost always pure polymers are dielectrics. The addition of nanofillers, such as graphene and its derivatives, has been successfully used to create conductive composites based on insulating polymers. The final properties of nanomodified composites can be influenced by many factors, including the type and intrinsic properties of nanoscale objects, their dispersion in the polymer matrix, and interphase interactions. The work deals with modeling of effective electric conductive properties of the representative volume elements of nanoscale composites based on a polymer matrix with graphene oxide particles distributed in it. In particular, methods for evaluating effective, electrically conductive properties have been studied, finite element modelling of representative volumes of polymer matrices with graphene oxide particles have been performed, and the influence of the tunneling effect and the orientation of inclusions on the conductive properties of materials have been investigated. The possibility of using models of resistive strain gauges operating on the principle of the tunneling effect is studied. Based on the finite-element modeling and graph theory tools, we created approaches for estimating changes in the conductive properties of the representative volume elements of a nanomodified matrix subjected to mechanical loading.

Synthesis and applications of zinc oxide for removal of various pollutants: A review

The versatility of zinc oxide applications in the removal of various pollutants has attracted a wide interest of researchers in the past decade. Numerous studies reported on zinc oxide synthesis pathways and resulting nanoparticle morphologies, applications, formation mechanisms and synthesis parameters. In this review the reported zinc oxide synthesis methods are classified into chemical, physical and biological routes; they are evaluated in terms of the required chemicals, synthesis conditions and the resulting morphologies and properties of zinc oxide. The chemical route of zinc oxide synthesis covers precipitation, micro-emulsion, solgel, solvothermal and hydrothermal paths. The physical route includes laser ablation and high energy ball milling, while the biological route covers plant extracts and microbe mediated synthesis. The mechanisms of zinc oxide formation of the mentioned routes are based on one or more of the following processes: particle nucleation, diffusional growth, Ostwald ripening, particle aggregation and sintering. The most influencing synthesis parameters overall are temperature, drying duration and additives’ effect. Higher temperatures (>200°C) commonly produce larger particles of zinc oxide (> 80 nm); the prolong duration (> 60 min) often results in the agglomeration and sintering of zinc oxide particles. However, additives may mitigate agglomeration extent. Overall, the chemical route is more preferable due to its flexibility that is also linked to the greater variability of zinc oxide particles. The physical method produces more consistent zinc oxide particles but requires higher energy inputs. The biological method is very promising and associated with low chemicals consumptions and good quality of zinc oxide.