A local green composite study: the effect of edible oil on the morphological and mechanical properties of PBS/bentonite composite

Composites of a biodegradable thermoplastic aliphatic polyester, polybutylene succinate (PBS), with bentonite were investigated for morphological and mechanical properties. The bentonite was modified with soybean oil (SBO) and lard oil (LO) (2:98 clay:oil % by weight) by mechanical stirring and ultrasonication. The PBS/modified bentonite composite was prepared by using an internal mixer and processed by compression molding. Under bentonite modification conditions, XRD and SEM showed that the bentonite layers were broken into small layers, and the d-spacing between the layers was increased by edible oil molecules. A small plate like structure of modified bentonite composite was observed by SEM micrograph, which revealed short and long layer silicate structure non-directionally throughout the matrix phase. The mechanical properties of PBS were reinforced by this structure. The tensile modulus and elongation at break seem to depend on its directional bentonite. Interestingly, considerable improvement in impact strength was observed at over 2 wt% of clay. The impact strengths of PBS, PBS/modified BTN with SBO composite, and PBS/modified BTN with LO composite were increased from 1 to 1.5 and 2 kJ/m2, respectively. Comparatively, using LO modified bentonite had a better performance for increased interlayer and resulted in higher impact strength of the composite than that of SBO composite. The results demonstrated that PBS/modified bentonite using edible oil could be a potential alternative low cost, eco-friendly material with superior impact properties useful for further applications.

Characterization of Bacterial Nanocellulose - Graphite Nanoplatelets Composite Films

Bacterial cellulose (BC) was synthesized from pineapple peel extract media with addition of fermentation agent bacteria Acetobacter xylinum. BC was disintegrated from the pellicle into bacterial nanocellulose (BNC) by using a high-pressure homogenizer (hph) machine, which has a three-dimensional woven nanofibrous network. The synthesis of composite films started when BNC, graphite nanoplatelets, and cetyltrimethylammonium bromide (CTAB) were homogenized using an ultrasonic homogenizer then baked on a glass mold at a temperature of 80 degrees Celcius for 14h. A scanning electron microscope (SEM) was used to analyze its morphology. X-Ray diffraction spectra were used to analyze the composite films structure. The functional groups of the composite films were analyzed using the FTIR spectrum. SEM micrograph shows that GNP was evenly distributed into BNC matrix after CTAB addition. GNPs are shown as flat and smooth flakes with sharp corners. Some peak corresponds O-H, C-H, C≡C, and CH3 stretching was identified by using FTIR spectroscopy at wavenumber 3379, 2893, 2135, and 1340 cm-1, respectively. XRD analysis shows that Crystalline Index (C.I) of BNC increases after 2.5 wt% addition of GNP. The presence of CTAB decreases C.I value of composite films. BNC/GNP composite films have the best mechanical properties with Young’s modulus about 77.01 ± 8.564.

Effect of Rice Flour Types on the Properties of Nonwoven Pineapple Leaf Fiber and Thermoplastic Rice Starch Composites

Thermoplastic starches and a nonwoven pineapple leaf sheet (NPALF) were prepared. Two types of flours were used to prepare thermoplastic starches (TPSs) which were Rice flour thermoplastic starch (RTPS) and Glutinous rice flour thermoplastic starch (GTPS). Two layers of thermoplastic starches and NPALF layer were sandwiched and pressed by a hot pressing machine at 150°C with 1500 psi for 15 min. All composites were investigated their densities and tensile properties. The density of all composite types had a lower density than each neat TPSs and types of rice flours did not affect their densities. The tensile property results confirmed NPALF could be used as a reinforcing agent both in GTPS and RTPS composites but their tensile improvement effectiveness in both systems are different. NPALF composite with RTPS did not affect the tensile strength but provided a slight improvement in modulus. Remarkably, NPALF composite using GTPS explored the great improvement performance both in strength and modulus which were increased up to 174% and 308% comparing with neat GTPS. SEM micrograph evidence clearly showed good wetting between GTPS and the reinforcement layer in the composite. This is resulting in the NPALF-GTPS composite showed a strong improvement in tensile properties.

FRESH STATE AND MECHANICAL PROPERTIES OF ULTRA-LIGHTWEIGHT FOAMED CONCRETE INCORPORATING ALKALI TREATED BANANA FIBRE

For a Lightweight Foamed Concrete (LFC) to efficiently function as an energy-saving building material, its self-weight (density) should be reduced. However, the problem associated with a reduced density is a decline in strength. To improve the mechanical properties of LFC, this research attempts to integrate banana fibre into LFC composite with a focus on fresh and harden state properties. An Ultra-Lightweight Foamed Concrete (ULFC) with a density of 600 kg/m3 was produced with the inclusion of treated and untreated banana fibres. The volume fractions of banana fibre added into LFC were 0.00% (control specimen), 0.25%, 0.35%, 0.45% and 0.55%. In addition, an optimised batch mix of ULFC reinforced with 0.35% untreated banana fibre was produced. The batches were tested for rheological, physical, and mechanical properties. Findings reveal that the workability of ULFC composites decrease with increase in fibre addition. The compressive, flexural, and tensile strengths of the alkali-treated composites were higher than the untreated banana fibre composite. SEM micrograph reveals that defibrillation of bundle fibrils due to cleaning the surface amorphous hemicellulose, lignin and pectin of the alkali-treated fibre, leads to rough surfaces and increase surface area resulting in better interfacial adhesion of the fibre with cement matrix.

Toxicity Evaluation of Arsenic Nanoparticles on Growth, Biochemical, Hematological, and Physiological Parameters of Labeo rohita Juveniles

The present study aims to assess the induced nanotoxicity of arsenic nanoparticles (AsNPs) on different organs of fresh water fish Labeo rohita. AsNPs were synthesized by chemical reduction method using sodium arsenite as precursor, ice-cold sodium borohydride as reducing agent, and sodium hydroxide to adjust the solution pH. The synthesized AsNPs were characterized by UV-Vis spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) for optical, structural, and morphological investigations. The UV-Vis absorption peaks occurring at around 300 nm indicated the presence of AsNPs in colloidal sample. The rhombohedral crystalline nature and metallic purity of AsNPs with crystallite size of 30 ± 1 nm were confirmed by characteristic peaks of XRD pattern. The SEM micrograph revealed the almost spherical shape and 40 ± 10 nm average size prepared AsNPs. For assessment of induced nanotoxicity, juveniles of Labeo rohita (L. rohita) were exposed to three different concentrations of AsNPs (namely, 1, 10, and 20 mg/L) for 30 days (n = 15 per group), and the control fish was kept untreated. It was observed that the routine behavior activities (such as swimming, mutual interactions, and feed intake) were affected by AsNPs. The growth of AsNPs treated fish was found retarded as compared to the control fish. Total erythrocyte count, total leukocyte count, and hemoglobin and hematocrit values were low in the AsNPs treated fish. Immunobiochemical assays revealed that protein level was altered in the AsNPs treated fish. The levels of antioxidant enzymes catalase and superoxide dismutase were low in the treated fish. The histological alteration induced by AsNPs in liver, gills, and kidneys demonstrated the damage in form of glomerulus shrinkage, vacuolation, inflammation, necrosis, lamellar disorganization, and hemorrhage in comparison with untreated fish. The results of the present study indicate that AsNPs exposure causes behavior, growth, hematology, immunobiochemical, and histological shortcomings in L. rohita.

Characterizations of Spray Deposited CdTe Thin Film

The spray pyrolysis is promising technique for deposition of CdTe thin film. We deposited CdTe thin film on glass substrate by homemade spray pyrolysis technique at substrate temperature 3000C. The CdTe thin film was characterized through Field scanning electron microscopy (FSEM), Energy dispersive X-ray analysis (EDAX), Uv-Visible spectroscopy. The SEM micrograph shows the film was uniform coverage, large number of densely packed grain whosesizes ranging from 474nm to 1.64µm. From EDAX analysis conform that the presenceof Cd and Te in prepared film with elemental stoichiometry of Cd and Se was 50.28% and 49.72% respectively. The optical absorption coefficient of the film of order of 106 and band gap of the film 1.45eV.

Structural and Surface Characteristics of CuO and Pt/CuO Nanostructured Thin Films

The most prominent and utilizable platinum-coated copper Oxide nanostructured thin films are prepared using the SILAR method. Their structural properties have been studied using X-ray diffraction (XRD) and Raman spectroscopy. XRD pattern reveals the phase purity and crystallinity of CuO nanostructures. The average grain size estimated from XRD gives diameters in the range of 14 - 27 nm. Raman spectra explain the structural information of CuO and Pt/CuO nanostructured thin films, in which the peaks observed at 328 cm-1, 609.32 cm-1 and 1141.77 cm-1 are the different phonon modes of CuO. The peak at 2136 cm-1 provides strong evidence for the formation of platinum on CuO nanostructures. The SEM micrograph confirms the floral morphology, which is composed of nano petals. From the observed morphology, it is observed that the deposited thin films such as CuO and Pt/CuO will give interesting applications to our society by being self-cleaning agents, photocatalysts, semiconductor devices, optical fibers, … etc. Keywords: CuO, Pt/CuO, Structural analysis, SILAR, Crystallinity.

Biotribological performance of medical-grade UHMW polyethylene-based hybrid composite for joint replacement

Ultra high molecular weight polyethylene (UHMWPE) is widely used for articulating surfaces in total hip and knee replacements. In the present work, the tribological properties of UHMWPE-based nano composites were studied in order to meet the demands of current bearing applications. UHMWPE matrix reinforced with 0.5, 1, and 2 weight percentage of alumina nano powder were fabricated by hot pressing. The dispersion and microstructure of composite material was established by X-ray diffraction (XRD) and scanning electron microscope (SEM) micrograph. The tests were carried out on a reciprocating sliding pin-on-disc tribometer at human body temperature (37±1°C) under dry and human serum lubricating environments for a normal load of 46 N and 52 N, a constant sliding speed of 4 mm. Under these testing conditions, it has been observed that the wear behavior of the developed composites improved with increase in weight percentage of alumina nano powder. The results show that at 52 N load, the maximum value of wear rate was 7.9x10−7 mm3/Nm and the minimum value 1.6x10−7 mm3/Nm was obtained. SEM was used to examine the worn surface and it was observed that human serum adheres to the surface of the composite pins upon sliding, resulting in the formation of a film which results in better wear resistance of the composite pins under human serum lubrication than dry sliding. This study implies that the use of nano alumina power will reduce the wear of UHMWPE based composite under human serum lubrication.

Mechanical and tribological behavior of Al composites containing varying beryllium aluminum silicate and constant CeO2

The main aim of the present work is to see the performance of “Al–Beryl” composites processed via stir casting route with or without CeO2 on their mechanical, wear and corrosive properties for structural applications in heavy machinery and watercrafts. Hardness and ultimate tensile strength increased with 36% and 43%, respectively, with 9% Beryl addition. Further, effect of addition of constant 0.5 wt.% CeO2 in “Al–Beryl” composite was evaluated and remarkably improvement in corrosion resistance was observed. Tribological performance of the composites was investigated by conducting sliding wear tests against steel at different loads in dry and wet conditions. Characteristic features of adhesion, fracture and delamination were observed in SEM micrograph of the worn composite having low beryl content slid in air whereas abrasive wear predominates in water or oil. Addition of increased wt.% of beryl particles led in reduced wear of the composite at all loads. Increase in corrosion resistance by 45% decrease in weight loss with 0.5% CeO2 addition was observed. “Al6061–9% Beryl–0.5% CeO2” composite with high hardness, wear and corrosion resistance is found most promising for structural applications. Article Highlights An increase of 36% in hardness and 43% in ultimate tensile strength was found in Al composites with 9% Beryl addition; Coefficient of friction was found least for “Beryl–CeO2” added composites in wet sliding conditions; A transition in wear mechanism occurred with adhesion, fracture and delamination of the worn composite with low beryl content slid in air; Corrosion resistance increased by 45% with 0.5% CeO2 addition in Al composites.

Scientific Advances and Pharmacological Applications of Marine Derived-Collagen and Chitosan

This work is devoted to investigating the effect of arc welding energy on microstructures and mechanical properties of steel 316L. This later is very useful in industrial, infrastructure transportation, containers shipping, and almost logistic applications. For that reason, five samples of welded steel 316L were carried out based on many parameters to reveal some properties (microstructure, mechanical, corrosion resistance, etc.). To reveal the anticorrosion efficiency. The epoxy/Alumina composite coating on welded steel 316L is tested in 1M HCl acidic media. This manipulation shows excellent corrosion resistance thanks to epoxy/Alumina coated. The choices of this coating are based on the environment, cost and safety. The used epoxy is only degrading with fire but not toxic. Also, it is not a costly method, and it is widely used and performed. Impedance studies on samples of welded steel 316L were conducted in 1M HCl media. The results showed that transfer resistance is increasing with the increase of welding energy. This result was assessed by potentiodynamic polarization measurements indicating a noticeable reduction of current densities with welding energy decrease. The scanning electron microscope (SEM) micrograph was undertaken in order to check how far the studied samples are protected by the used coating in such aggressive media.