Current Materials Science - Volume 12, Issue 2, 2019

Background: This research aims to follow the concentration of carbon dioxide (CO2) in the atmosphere and the effect of zero-emission on the ecosystem. CO2 is the most important of the green house gases. Nowadays, the earth is suffering from global warming due to greenhouse gases. The call all over the world is to reduce the emission of the greenhouse gases, mainly CO2. Methods: The research methodology depends on the data of international research laboratories, which follow the concentration of CO2, such as National Oceanic and Atmospheric Administration (NOAA), the USA, and Mauna Loa Observatory in Hawaii. The concern towards CO2 concentration in the atmosphere started in the last century. Results: The industrial revolution did not consider the impact of pollution on the environment. The impact on the environment was noticed only after a clear disturbance in the ecosystem. The emission of greenhouse gases, especially, CO2 is monitored; daily, monthly and yearly. There are different sources of CO2 emissions, such as transportation, factories, burning of forests etc. In fact, CO2 is a harmful as well as a useful gas. It is harmful because of global warming, and useful because of its important role in the photosynthesis process. This process is very crucial for all living things. The research to reduce the emission of CO2. has provided some solutions. Layered materials, MPS3, where M stands for the transition metal, have been used to store hydrogen gas. The hydrogen molecule size is 2.89 Å, and the molecular size of CO2 is 3.3 Å, this means that the CO2 can be captured by the layered materials. The capturing of CO2 is achieved by simulation. Conclusion: We need to reduce the emission of CO2 but not to reach zero emission, because then, there will be no photosynthesis process, which means there will be no life on the earth. Carbon capture and storage is a technology that can capture up to 90% of the CO2, but the biggest obstacle to this approach lies in the inherent thermodynamic stability and kinetic inertness of CO2.

Background: Natural plant-based materials have several advantages. They are biodegradable, biocompatible, non-toxic, cost-effective, environment friendly, easily available, and can undergo chemical modification. Objective: Grewia asiatica extracts contain various phytoconstituents and have therapeutic benefits such as antimicrobial and anti-diabetic properties. They form colloidal dispersions and make a highly viscous gel in water. Considering these properties of Grewia asiatica mucilage, the present work was aimed to investigate its application in the formulation of gel for the topical delivery of diclofenac sodium. Methods: Gel formulations were prepared with and without penetration enhancers using 1% w/w diclofenac sodium as a model drug. The formulations were subjected to different evaluation tests like physical characterization, pH, spreadability, skin irritation, gel retrogradation, drug content and in vitro drug diffusion. The in vitro diffusion of the drug from different formulations was compared with the in vitro drug release profile of the marketed formulation (Omni gel, Cipla, India). To assess the release mechanism, the in vitro release data was analyzed using Korsmeyers-Peppas’ equation. Results: The mucilage showed good gelling behavior in 5.50, 5.75, 6.00, 6.25 and 6.50% concentrations. All the formulations followed the anomalous transport mechanism of drug release. The formulation BP3 showed 90% of drug release after 5.2h of dissolution study, which was similar to the marketed formulation. Hence, formulation BP3 was ideal among all the formulations. Conclusion: It might be concluded that, the Grewia asiatica mucilage may be used as a natural polymeric material for gel formulation.

Background: The exploitation by the industries of vegetable fibers in the field of composite materials has made it possible to reduce the dependency of oil which is the result of their mechanical properties, their thermal resistance and biodegradability. Methods: In this work, we carried out a comparative study by a genetic simulation on two materials based on different natural reinforcements (Bamboo and Coconut) to see the influence of its fibers on the elastic behavior of bio-composite materials. Results: The results of our genetic simulation showed that Bamboo / Epoxy is more resistant than Coconut / Epoxy and that shear damage of Bamboo / Epoxy is lower than that of Coconut / Epoxy by 11 to 12.5%. Conclusion: The results are similar to the results given by Rao KMM where he showed by experimental tests that Bamboo fiber is the most resistant when compared with other fibers especially coconut fiber.

Background: The technological enhancement in various disciplines enhances the demand for the new material which can replace the conventional materials. This has initiated the idea of composite materials. Synthetic fiber reinforced polymer matrix composites are being widely used due to its mechanical properties, but these fibers lack in terms of biodegradability, initial processing cost, recyclability and health hazard. An alternative to tackle these drawbacks can be found in natural fibers, that give an advantage in terms of strength to weight ratio, ease of availability and biodegradability. Methods: This work is aimed to determine the effect of hybrid basalt - banana reinforced epoxy composite and their effectiveness in substituting few conventional materials in terms of their mechanical properties, wear resistance and water absorption rate. Results: Basalt Banana Hybrid Composite (BBHC) is tested for their mechanical strength, hardness, impact strength, flexural strength, wear rate and water absorption rate. The test results of mechanical properties for the BBHC are compared to the other hybrid materials and conventional materials. Conclusion: The test results reveal that the hybrid basalt banana epoxy composite is a good substitute over various conventional materials. The water absorption test results reveal that the hydrophilic nature of the natural fibers reduces a lot after the hybridization.

Background: Peri-prosthetic infections are characterized by high resistance to systemic antibiotic therapy. In this work, commercial PMMA-based bone cement has been loaded with a bioactive glass doped with silver ions, with the purpose to prepare composite bone cement containing a single inorganic phase with both bioactive and antibacterial properties, able to prevent bacterial contamination. Methods: The glass distribution in the polymeric matrix, the composites radio-opacity, the bending strength and modulus, the morphology of the fracture surfaces, the bioactivity in Simulated Body Fluid (SBF) and the antibacterial effect were evaluated. The glass particles dispersion in the polymeric matrix and their exposition on the polymer surface have been assessed by morphological and compositional characterizations via Scanning Electron Microscopy (SEM) and Energy Dispersion Spectroscopy (EDS). Results: The introduction of the silver-doped bioactive glass allowed imparting an intrinsic radio-opacity to the cement. The bending strength and modulus were influenced by the glass preparation, amount and grain-size. The polymeric matrix did not affect the composite ability to induce hydroxyapatite precipitation on its surface (bioactivity). Moreover, antibacterial test (inhibition halo evaluation) revealed a significant antibacterial effect toward S. aureus, Bacillus, E. coli and C. albicans strains. Conclusion: The obtained results motivate further investigations and future in vivo tests.

Background: Luminescence glass is a potential candidate for developing white light emitting diode (W-LED) due to its good rare earth ion solubility, efficient luminescence, easy fabrication and good mold ability. Pr3+ ion has various visible emission bands from blue to red spectral region, and has attracted considerable attention for potential application to LEDs, ultraviolet laser, and scintillator. The Dy3+ ions can exhibit emission in blue and greenish-yellow (4F9/2→6H15/2, 13/2 transitions of Dy3+) spectral regions under excitation at near UV (ultraviolet). It is possible to obtain white luminescence if Pr3+ ions and Dy3+ ions can be excited simultaneous, due to their multiple luminescence in the visible region. Methods: The Pr, Dy doped ZnSiCa glass samples were prepared by the conventional melting quenching procedure. The XRD, absorption spectra, emission spectra, and ICP-OES measurements were performed to investigate the properties of the materials. Results: The Pr and Dy co-doped ZnSiCa glasses under 443 nm excitation show emission band peaking at about 483 nm, 575 nm and 670 nm / 676 nm. The glass samples exhibit chromaticity coordinates in the white light region in the CIE 1931 diagram, with a Correlated Color Temperature (CCT) at about 7000 K. Conclusion: Pr, Dy codoped ZnSiCa glass samples show chromaticity coordinates in the white light region in the CIE 1931 diagram, with a CCT at about 7000 K. It is suggested that the Pr, Dy codoped ZnSiCa glasses might be considered as promising candidates for white light emitting sources.

Introduction: Pigments have become the largest colorant group for textile prints because pigment printing is the oldest and cheapest method. Binders are used to fix pigments to the fibers by adhesion. Pigment binders play a significant role in pigment printing because it encloses the pigment particles and adheres to the fiber. Objective: In this study, cotton/polyester blend fabrics were treated with ultraviolet light (UVB) at an air pressure of 1 atm to improve printability. Methods: To study the influence of pretreatment time, experiments were carried out at different exposure times. Untreated and UV treated fabrics were analysed by Fourier-transform infrared spectroscopy to investigate changes in the chemical composition of fabrics. It was observed that carbonyl groups were formed on the surface of UV pretreated cotton fibers. Scanning Electron Microscopy (SEM) was used to investigate the roughness and cracks on the treated fiber surface. Then, all UV treated and untreated fabrics were screen printed with different kinds of pigments. The color strength of the printed fabrics and fastness properties to washing and dry/wet rubbing were evaluated. Results: Experimental data showed that atmospheric UV pretreatment led to an increase in pigment uptake. Moreover, UV pretreated fabrics had better dry and wet rubbing fastness compared with untreated fabrics. Conclusion: The washing fastness of UV pretreated fabric showed no significant change and was comparable with that of untreated fabric. The loss in tensile strength of UV pretreated fabrics was greater than untreated samples.