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There is great interest in using natural materials in production, and this is due to ecological concerns. The two main pillars in developing natural composites are waste utilization and ensuring good economic returns. The biodegradability of natural fillers is one of the factors in expanding their use in natural fiber-reinforced composites. Naturally added composites, which are effectively used in different applications such as automotive, aviation, and maritime as well as design and construction industries, offer improved mechanical and tribological properties to the material. In the study where the mechanical effects of natural additives on the polymer were examined, waste banana peel powder and rice peel powder were added to polypropylene at different concentrations. After melt mixing of the components forming the composite, injection molding was performed. To determine the mechanical properties, tensile, hardness, Izod impact strength and density tests were carried out, and the microstructure examination of the composites was carried out with a scanning electron microscope. As a result of the studies, adding natural additives to the polymer caused the impact properties, elongation amount and tensile strength to deteriorate. In addition, with the increase in the reinforcement ratio, the density, hardness and elastic modulus of polymer composites increased. [ABSTRACT FROM AUTHOR]

The main objective of this study is to fabricate composite materials having excellent thermal, mechanical and electrical properties for thermal and electronic applications. In this work, strontium feldspar-containing composites (Sr-feldspar/cordierite and Sr-feldspar/Sr-osumilite) were prepared by solid-state sintering of SrO-containing cordierite (MgSrAl 4 Si 5 O 18)/borosilicate glass powder mixtures. The phase composition, physical properties and microstructure of sintered composites were investigated by X-ray diffraction technique, water displacement method and scanning electron microscope, respectively. Moreover, the thermal expansion coefficient, hardness, and electrical properties were also measured. The results of X-ray patterns revealed the crystallization of Sr-feldspar and cordierite in the composites that contain up to 20% borosilicate glass. On the other hand, the composites that include more than 20% glass, displayed the crystallization of Sr-feldspar and Sr-osumilite with little amount of cristobalite. The bulk density values of sintered composites were decreased from 2.41 to 1.84 g/cm3 with increasing the amount of added glass. The microhardness values were increased from 519 to 710 kg/mm2 with increasing the glass content. Low thermal expansion coefficient (2.65 × 10−6, 2.22 × 10−6, 3.45 × 10−6 and 4.26 × 10−6 K-1 for C0, CG91, CG73, CG55, respectively) and low dialectic constant (7–8.5) were obtained for the prepared composites. [ABSTRACT FROM AUTHOR]

In this present study, the fused deposition modeling (FDM) method was used to fabricate the composites. Before three-dimensional (3D) printing, samples were designed according to the ASTM D256, D790 and D3039 standards for impact, flexural and tensile tests, respectively, using Onshape software before conversion to an STL file format. Afterward, the digital file was sliced with infill densities of 60%, 80%, and 100%. The composite samples contained chopped carbon fiber (cCF) and poly lactic acid (PLA), as reinforcement and matrix, respectively. The cCF/PLA (simply called cCFP) filaments were printed into various cCFP composite (cCFPC) samples, using a Viper Share bot 3D machine with different infill densities before the aforementioned mechanical testing. The tensile strength of cCFP were obtained as 25.9MPa, 26.9MPa and 34.75MPa for 60%, 80% and 100% infill density cCFP samples, respectively. Similarly, the flexural strength of cCFP were obtained as 11.8MPa, 12.55MPa and 18.4MPa and impact strength was 47.48kJ/m2, 48.45kJ/m2 and 48.96kJ/m2 for 60%, 80% and 100% infill density cCFP samples, respectively. The fractured/tested samples were examined and analyzed under a scanning electron microscope (SEM) to investigate the presence of fiber and void in the tensile sample. Based on the experimental results, it was evident that a high infill density of 100% with the highest reinforcement exhibited maximum impact strength, tensile and flexural strengths and moduli when compared with other lower carbon content of cCFPC samples. Therefore, the optimal 3D-printed cCFPC sample could be used for engineering application to benefit from properties of the polymer matrix composite materials and possibilities through additive manufacturing (AM). [ABSTRACT FROM AUTHOR]

Snake grass fiber was used as a supporting material in an epoxy matrix. The goal was to develop a lightweight structural material. To enhance the interfacial bonding between the snake grass (Sansevieria ehrenbergii) fiber and polymer matrices, the fiber underwent chemical treatment with NaOH. Samples were prepared with both neat and treated fibers mixed with epoxy at various volume percentages. The mechanical properties of snake grass fiber exhibited improvement with increasing fiber length and fixation, reaching optimal values at 20 mm length and 20% v/v fixation. Dynamic mechanical analysis (DMA) demonstrated superior energy absorption by the composite up to 140 °C, irrespective of repetition. Thermogravimetric analysis (TGA) indicated rapid degradation of untreated fiber with a residue level of 0.2%, while the snake grass composite (25% v/v) exhibited stable residue content at 11%. Microscopic evaluation using a scanning electron microscope provided insights into the morphology of the fiber surface. [ABSTRACT FROM AUTHOR]

The direct impregnation approach is used to synthesize nickel dimethylglyoxime (NDG) on γ-alumina (γ-Al2O3) composites to be used as a catalyst. The structural, thermal, and magnetic characteristics of γ-Al2O3, NDG, and NDG/γ-Al2O3 composites are investigated and their photocatalytic performance towards methylene blue (MB) and methyl orange (MO) is examined. The finding supports the use of NDG over γ-Al2O3 as catalysts, besides their enhanced thermal stability. The scanning electron microscope (SEM) and transmission electron microscopy (TEM) demonstrate that the catalyst particles are dispersed uniformly, indicating that the Ni microcrystalline or Ni nanoparticles on γ-Al2O3 are most likely distributed in a single phase and/or in a homogenous route. X-ray diffraction (XRD) results together with the results of SEM and TEM indicated that NDG/γ-Al2O3 nanocomposite catalysts can be prepared effectively by impingement approach. The average crystallite size of γ-Al2O3 is 6 nm, whereas the average crystallite size of NDG/γ-Al2O3 composites is 10 nm. Both γ-Al2O3 and NDG/γ-Al2O3 composites have a weakly diamagnetic response, whereas NDG exhibits poor ferromagnetism response. The calculated values for the photodegradation efficiency, after UV–visible irradiation for 130 min, towards MO dye employing γ-Al2O3, NDG, and NDG/γ-Al2O3 composites as a catalyst are 74.2, 36.7, and 61.7%, respectively, whereas their values towards MB dye are 17.8, 5.3, and 19.1%, respectively. Furthermore, when NDG was combined with γ-Al2O3 to form NDG/γ-Al2O3 composites, the degradation performance was significantly improved and could be suitable for the degradation of other dyes. [ABSTRACT FROM AUTHOR]

In a nitrogen atmosphere, a novel composite, Poly(Acrylonitrile‐co‐Acrylamide)/crab shell powder, was synthesized by combining two monomers, acrylonitrile (AN) and acrylamide (Aam), with varying weight percentages of crab shell powder (CSP) as bio‐filler. The synthesized composite Poly (AN‐co‐Aam)/CSP, copolymer Poly (AN‐co‐Aam), and CSP were characterized using Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), thermogravimetric (TGA) analysis, derivative thermogravimetric (DTG) analysis, and a scanning electron microscope (SEM). The mechanical properties, like tensile, flexural, and impact strengths, were studied. The hardness, biodegradability, and water absorbency properties have been studied using appropriate methodologies. The SEM images and FTIR data confirm the appropriate synthesis of the composite material and the uniform distribution of CSP. The mechanical strength increases with the rise in concentration of CSP up to 20 wt. % and then gradually decreases. The thermal analysis reveals that the composite exhibits adequate thermal stability. The artificial neural network (ANN) model is used for the prediction of mechanical properties, which shows adequate results with the experimental results. The training and test datasets use a correlation factor associated with this analysis that is higher than 0.9, which confirms that the expected values of the mechanical performance are an excellent comparison to the experimental value. [ABSTRACT FROM AUTHOR]

In this work, the Al–xMg–MgO composites were fabricated via stir casting method. The different amounts of Mg (1, 3 and 5 wt%) and MgO (0.5, 1.0 and 1.5 wt%) were added to the aluminum matrix, and the composites were casted at various temperatures of 700, 800 and 900 °C. The effects of the casting temperature (°) and the Mg (wt%) and MgO (wt%) ratios on the microstructure, physical and mechanical properties of the composites were investigated. The scanning electron microscope with electron-dispersive spectrum, density (g/cm3), porosity (%), hardness (HR-15T) and compression (MPa) test analyses were conducted on the composites. The results were also analyzed with the Taguchi experiment design method with ANOVA. The properties of the composites changed depending on the process parameters and ratios of Mg element and MgO particles. The minimum density and porosity contents were obtained as 2.62 g/cm3 and 0.6%, respectively. The increase in the casting temperature contributed to the wettability and so the properties of the samples to some extent. The additions of Mg and MgO improved the hardness (72.8 HR-15T) and compression strength (646.4 MPa) of the composites. It can be said that the main strengthening mechanisms of the Al–xMg–xMgO composites for this study were the solid solution and dispersion strengthening mechanisms. [ABSTRACT FROM AUTHOR]

BACKGROUND: Polyetheretherketone materials have the advantages of stable physical, chemical and mechanical properties, radiation transparency and elastic modulus similar to human bones, but there is a biological inertia problem, which limits its clinical application. OBJECTIVE: To evaluate the biocompatibility of polyetheretherketone/hydroxyapatite composites prepared by fused deposition molding 3D printing. METHODS: Polyetheretherketone and polyetheretherketone/hydroxyapatite composite materials (hydroxyapatite mass fraction 10%) were prepared by fused deposition molding 3D printing technology, which were denoted as polyetheretherketone group (control group) and polyetheretherketone/hydroxyapatite group (experimental group). Passage 3 mouse preosteoblasts (MC3T3-E1) were co-cultured with the extracts of the two groups of materials, separately. Cells cultured alone were used as positive controls. The survival and proliferation of MC3T3-E1 were detected by Live/Dead fluorescence staining and CCK-8 assay. The adhesion growth and proliferation of MC3T3-E1 on the surface of the materials were observed by scanning electron microscopy. RESULTS AND CONCLUSION: (1) Live/Dead fluorescence staining exhibited that the MC3T3-E1 cells in two kinds of extracts grew well and presented good viability. The cell survival rate was higher than 90%. The two materials had no obvious cytotoxicity. The cells proliferated well with the extension of culture time. (2) The results of CCK-8 assay showed that the cytotoxicity of the two kinds of materials was qualified. The proliferation absorbance value of cells in the experimental group was higher than that of positive control group and control group at 3, 5 and 7 days of culture (P < 0.05). (3) Scanning electron microscope observation showed the good adhesion and cell spreading. Matrix secretion of MC3T3-E1 cells was numerous in the experimental group at 1 day of inoculation. The number of cells adhering to the surface of the two groups of materials increased, and more matrixes were secreted at the same time, among which the number of cells adhering to the surface of the experimental group and the secretion of matrix were more at 3 days of inoculation. The overlapping growth of cells appeared on the surface of the two groups of materials, and the cells in the experimental group were more efficient in spreading growth and secreting matrix at 7 days of inoculation. (4) These findings verify that the polyetheretherketone/hydroxyapatite composite prepared by 3D printing has good biocompatibility. [ABSTRACT FROM AUTHOR]

Zinc oxide has been shown to be a potential photocatalyst under UV light but its catalytic activity is limited under visible light due to its wide bandgap energy and rapid recombination of electrons and holes. Besides the catalytic recovery is a challenging issue because of its dispersion in solution. Previous work has shown that the interaction of gold nanoparticles with ZnO can reduce the band gap energy (Eg) and plasmon resonance (SPR) as well as the formation of the Schottky barrier in Au/ZnO composite can reduce the recombination of electrons and holes. In this study, Au/ZnO/Fe3O4 (AZF) composites were prepared by a simple mixing method using polyvinyl alcohol (PVA) as a binder. As-prepared composites were characterized by Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDS), X-ray Diffraction (XRD), UV-Vis Diffuse Reflectance (UV-Vis-DR), and Fourier Transform Infra Red (FT-IR). The catalytic efficiency of as-prepared samples was evaluated through the decomposition of tartrazine (TA), a colorant that is difficult to decompose in wastewater and has harmful effects on human health. The effects of reaction parameters such as the content of PVA, solution pH, and oxidizing agents (O2 and H2O2) on the catalytic efficiency were studied. The AZF at PVA of 0.0125 g showed the highest performance among as-prepared samples. With the presence of 12 mM H2O2 in the catalyst system, the degradation efficiency and reaction rate of TA in composite increased to 81.5% and 0.020 min-1, respectively. At this condition, photocatalysis and Fenton system catalysis occurred together. The catalytic mechanism of Tartrazine (TA) on composite was proposed and the reaction of TA was studied by the first-order kinetic model. [ABSTRACT FROM AUTHOR]

Polyethylene terephthalate (PET) pre-prepared nano/micro fibers were treated by sodium hydroxide (NaOH) aqueous solution and then AgNPs were loaded on them through the soaking process. In total, eight samples were created. Then they were characterized by field emission scanning electron microscopy (FESEM), scanning electron microscopy (SEM), X-ray energy diffraction (EDS) spectroscopy and Fourier transform infrared (FTIR). Disk diffusion and colony counting tests were also performed. Samples containing AgNPs had growth inhibition zones with diameters between 19 and 26 mm while control samples had no inhibition zone. PET microfibers containing AgNPs had a larger inhibition zone on Staphylococcus aureus compared to other samples. The innovation of this research is the placement of AgNPs on the hydrophilic PET micro/nano fibers. [ABSTRACT FROM AUTHOR]

Novel ternary composite photocatalysts have been successfully prepared by TiO₂ nanofibers, reduced graphene oxide, and CdS nanoparticles (TiO₂/rGO/CdS) by using electrospinning technique with easy chemical methods. The structures and their properties are examined by X‐ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS), and field‐emission scanning electron microscope (FESEM). The structural characterization of the composite reveals that pure TiO₂ NFs and CdS NPs crystalline very well and the reduced graphene oxide is tightly composed with TiO₂ NFs and CdS Nps. The photodegradation of methyl orange (MO) under UV light illumination is significantly enhanced compared with that of bare materials. This ternary composite degrades methyl orange within 75 min. The enhanced photocatalytic degradation performance resulted from effective separation of e–h pairs with rGO sheets and also contributed for high rate degradation efficiency. This novel ternary composite has a potential application of wastewater purification and utilization for energy conversions. [ABSTRACT FROM AUTHOR]

In the present study, a new composite based on epoxy resin reinforced with Lygeum spartum L. fibers was prepared using compression molding technique. Chemical, mechanical as well as morphological analyses were carried out on the Epoxy/Lygeum spartum composite (Epoxy/LS) using ATR-FTIR, tensile and flexural tests, and SEM spectroscopy. An increase in the intensity of several bands associated to the main complements of vegetable fibers (cellulose, hemicellulose, and lignin) was showan using ATR-FTIR analysis. An improvement in the mechanical properties of this new material was observed, with respect to the neat epoxy resin. This was of the order of 117 % and 85 % for tensile and flexural modulus respectively, and of the order of 40 % and 9 % for tensile and flexural strength, correspondingly. A good fiber-matrix adhesion was also observed from tensile fracture surface of composite using scanning electron microscope (SEM). All the obtained results demonstrated the effectiveness of the Lygeum spartum fibers as reinforcement of composite materials. [ABSTRACT FROM AUTHOR]

Metal oxide nano additives are widely used as a second phase modifier as they improve the properties of the matrix materials. Nano additives also supply various advantages for polymers which can be employed in additive manufacturing methods. Among the additive manufacturing methods, stereolithography is one of the most remarkable to produce nano‐modified polymers because of the easy nano modification of the photocurable resins. In the present study, we mixed the metal oxide particles; Fe2O3, ZnO, NiO, Al2O3, TiO2, and MgO with the photocurable epoxy and used the mixtures to print the specimens. We investigated the structural morphology, thermal and mechanical properties of the printed specimens with an optical microscope, scanning electron microscope, Fourier transform infrared spectroscopy, differential scanning calorimeter, differential thermogravimetric analysis, and microhardness, respectively. Findings proved the dilute agglomeration of the nano additives. Besides, nano additives can improve the thermal stability of the photo‐cured polymer. The microhardness of the Fe2O3 added polymers reached 27.63 HV levels while it was measured as 16.16 HV for the pristine samples (~70% raise was experienced). The maximum degradation temperatures of the polymer nanocomposite structures were measured in the range of 396–420 °C. [ABSTRACT FROM AUTHOR]

In this study, poly(pyrrole-co-o-aminophenol)/chitosan composite samples were synthesized by chemical method (as powder) in solutions of different molar ratios of pyrrole and o-aminophenol (8:2, 1:1 and 2:8). Composite samples were characterized by FT-IR (Fourier Transform Infrared), solubility tests, 1H-NMR (Nuclear Magnetic Resonance), DSC (Differential Scanning Calorimetry), CV (Cyclic Voltammetry) and SEM (Scanning Electron Microscope) images. As a results of the solubility test, it was observed that the solubility of the composite decreased as the pyrrole ratio increased. Also, the best solvents for composite samples determined as DMSO and DMF. When SEM images of copolymer and composite samples are examined, it is seen that the copolymer structure shows a structure in the form of regular small particles, while large nebula-shaped structures are formed after composite formation with chitosan. In addition, it was determined that the structures of the composite samples prepared in solutions containing different ratios of monomers differ from each other depending on the monomer ratios. According to DSC thermal analysis results of composite samples, it was concluded that the thermal stability of the composite samples having high pyrrole ratio (8:2) was better than the composite samples having low pyrrole ratio (1:1, 2:8). The electrochemical behavior of the composites was achieved by cyclic voltammetry technique. Electrochemical stability studies show that composite samples have good redox behavior, do not degrade during redox behavior, and are therefore very stable electrochemically. [ABSTRACT FROM AUTHOR]

The tribological performance of a glass fiber reinforced polyamide66 (GFRPA66) composite with varying fiber weight percentage (wt.%) [30 wt.% and 35 wt.%] is investigated in this study using a pin-on-disc tribometer. GFRPA66 composite specimens in the form of pins with varying percentages of fiber viz., 30 wt.% and 35 wt.% are fabricated by an injection molding process. Tribological performances, such as coefficient of friction (COF) and the specific wear rate (SWR), are investigated. The factors affecting the wear of GFRPA66 composites [with 30 wt.% and 35 wt.% reinforcements] are identified based on the process parameters such as load, sliding velocity, and sliding distance. Design Expert 13.0 software is used for the experimental data analysis, based on the design of experiments planned in accordance with the central composite design (CCD) of the response surface methodology (RSM) technique. The significance of the obtained results are analyzed using analysis of variance (ANOVA) techniques. To attain minimum SWR and COF, the wear performance is optimized in dry sliding conditions. The analysis of experimental data revealed that SWR and COF increased with increasing load, sliding velocity, and sliding distance for GFRPA66 [30 wt.%], but decreased with increasing polyamide weight percentage. The SWR for a maximum load of 80 N, and for a sliding velocity of 0.22 m/s, and a sliding distance of 3500 m for GFRPA66 composite specimens with 30 wt.% reinforcements are found to be 0.0121 m3/Nm, while the SWR for the same set of parameters for GFRPA66 composite specimens with 35 wt.% reinforcements are found to be 0.0102 m3/Nm. The COF for the GFRPA66 composite specimens with 30 wt.% reinforcements for the above set of parameters is found to be 0.37, while the GFRPA66 composite specimens with 35 wt.% reinforcements showed significant improvement in wear performance with a reduction in COF to 0.25. Finally, using a scanning electron microscope (SEM), the worn surfaces of the GFRPA66 are examined and interpreted. [ABSTRACT FROM AUTHOR]

In this paper, the double‐element composites were developed, which contained the epoxy resin as matrix phase and carbon black rubber powder as toughening materials. Quasi‐static compression tests on epoxy resin and different mass fractions carbon black rubber powder‐epoxy resin composites were performed in room temperature to test their compression properties. The energy absorption performance and the energy absorption efficiency of the composites were calculated according to the compression curve. The fracture characteristics of the micro appearance of the compressed material specimen were observed by scanning electron microscope. The deformation mode of the composite was analyzed. By systematically analyzing the effects of carbon black rubber powder content on the mechanical properties of carbon black rubber powder‐epoxy resin, it was found that carbon black rubber powder as a reinforced material could effectively improve the brittleness of epoxy resin, the yield strength and the adsorption properties and efficiency of composites. With the mass fraction of carbon black rubber powder increasing, the energy absorption performance of carbon black rubber powder‐epoxy resin first increases and then decreases. The most significant performance observed was at a mass fraction of 5 % in carbon black rubber powder‐epoxy resin composites. [ABSTRACT FROM AUTHOR]

A porous silicon-carbon composite was synthesized using a mixture of sucrose, ammonium chloride, and silicon in a neutral gas environment at 1000 °C. Effect of raw materials activation were studied (0, ‌ 1, 2, and 4 h) on the characteristics (microstructure, morphology, phase structure, carbon structure, and electrical resistance) of prepared composite powders using SEM (Scanning Electron Microscope), XRD (X-Ray Diffraction), RAMAN spectroscopy methods, and electrical resistivity measurements. Results showed that mechanical activation promoted the decomposition reaction of raw materials during heat treatment, helped to form spherical carbon particles, reduced carbon particle size (less than 200 nm), and facilitated the formation of the porous carbon structure. Raman spectra also showed the appearance of some carbon in the milled samples before the heat treatment process. Carbon peaks were not observed in the XRD patterns of composite powders due to the nanocrystalline structure of the carbon, while Raman spectra proved the presence of nanocrystalline and amorphous carbon in the structure of the prepared powders. Moreover, mechanical activation increased the content of nanocrystalline and amorphous carbon in the composite powders. Increasing the mechanical activation time up to 4 h, reduced the electrical resistivity of Si–C composite powders to 1.44 Ω-cm. [ABSTRACT FROM AUTHOR]

Glass fiber (GF) reinforced nylon56 composites (nylon56/GF) were prepared by melting and blending through twin‐screw extruder with continuous fiber feeding. The structure and properties of the composites were characterized by electron density tester, polarizing microscope, scanning electron microscope, electro‐mechanical universal testing machine and thermal analyzer. The results showed that the density of the prepared composites is less than 1.37 g/cm3. There is strong interface adhesion between glass fiber and nylon56 matrix in the composite system, and the glass fiber length in the system is 0.47–0.61 mm. With the increase in the content of high‐performance glass fiber, the mechanical properties of the composite are significantly improved. When four bundles of GF are added, the properties of the nylon56/GF composite are the best. The tensile strength of nylon56/GF composite reaches 160 MPa, 86.9% higher than that of nylon56. The bending strength is 180 MPa and increases by 98.7% more than that of nylon56. The flexural modulus is 7100 MPa and rises by 125.6% compared with nylon56, and the impact strength is 11 kJ/mm2, which is 307.4% higher than that of nylon56. The nylon56/GF composite has a low density and excellent performance and can be widely used in locomotive and wind power. [ABSTRACT FROM AUTHOR]

To reduce the pollution resulting from discarding waste plastic film and burning straw, a new method of preparing straw-reinforced LLDPE composites was developed to utilize these wastes. The straws were first laid parallel on an LLDPE film and then rolled up. The rolls containing long straws were laid into a mat and then hot-pressed into a long straw composite board (the mass of straw accounted for 60%). Slope-cutting the straw, grinding the straw, and twisting the roll were designed to improve the physical and mechanical properties of long straw composites. Among them, slope-cutting the straw combined with twisting the roll provided the best properties. Compared to the extruded straw particle composite, the composite prepared with the new method improved the tensile strength, bending strength, impact strength, and water resistance by 358%, 151%, 416%, and 81%, respectively. Slope-cutting exposed more inner surface at the end of the straw. Scanning electron microscope observations showed that the straw inner surface was more tightly bonded with the LLDPE matrix than the outer surface. Meanwhile, the integrity of the straw was retained as much as possible, and thus greatly improved the performance of the resulting composites. Dynamic mechanical analysis, differential scanning calorimetry, and thermogravimetric analysis show that the viscous deformation of the composites prepared by the new method was reduced and the rigidity was increased, and the combination of straw and LLDPE forms a dense composite material with good interfacial bonding. It greatly slowed down the degree of its pyrolysis. [ABSTRACT FROM AUTHOR]

Composite materials are materials that are made of two or more materials that remain separate and differ on a macroscopic level while forming a single component so as to produce a composite material that has different mechanical properties and characteristics from the material it forms. Particle composite materials consist of particles held together by a matrix. In this study, an epoxy resin matrix was used with Polymesoda erosa clam shell nanopowder filler. Nano-sized fillers have many advantages over macro-sized ones. The nano-sized particles will have a high surface area, thereby increasing the mechanical strength of the material. The powdered nanoparticles produced will be analyzed using Fourier Transform Infrared (FTIR), Transmission Electron Microscope (TEM), and Scanning Electron Microscope (SEM). Based on the results of SEM and TEM, the nanopowder of clamshell has a size below 100 nm. The FTIR results of the powdered shellfish showed the presence of carbonate bonds C-O, C=O, and Ca-O. [ABSTRACT FROM AUTHOR]

Using zinc-aluminum layered double hydroxides-laponite (LDH-LAP) complex as matrix, with the assistance of zwitterionic surfactants of hexadecyl dimethyl sulfobetaine (SB) and dodecyl dimethyl carboxyl betaine (DCB), the pesticides beta-cypermethrin (BCT) and imidacloprid (IMP) were inserted into the LDH-LAP to obtain BCT/SB-LDH-LAP, BCT/DCB-LDH-LAP, BCT/SB-DCB-LDH-LAP and IMP/DCB-LDH-LAP composites, respectively. Powder X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), thermogravimetric/differential thermal analysis (TGA/DTA) and scanning electron microscope (SEM) were used to characterize the structural properties of composites. BCT/SB-LDH-LAP, BCT/DCB-LDH-LAP, BCT/SB-DCB-LDH-LAP and IMP/DCB-LDH-LAP had larger interlayer distances of 4.29, 4.33, 4.33 and 4.61 nm, which were bigger than those of SB-LDH-LAP (3.87 nm), DCB-LDH-LAP (3.83 nm) and LDH-LAP (1.65 nm). The FT-IR and TGA/DTA results further confirmed the existence of SB, DCB, BCT and IMP into LDH-LAP. The pesticide releases were investigated and analyzed in pH 5.0 and 6.8 buffer solutions. The release behaviors can be fitted by pseudo second-order and parabolic diffusion models. The composites based on LDH-LAP could be suggested to potential application for controlled-release of the pesticide. [Display omitted] [ABSTRACT FROM AUTHOR]

Nowadays, the natural fibers reinforced thermoplastic polymers have been increasingly used in various automotive, construction, and packaging industries because of their high modulus, strength, and renewability. In this work, the thermoplastic polymer is reinforced by surface‐modified Bauhinia Vahlii (BV) fiber. The fabrication of composite at 10, 20, and 30 wt% BV fiber loading is done by compression molding technique and characterization of the composite is carried out. The tensile and flexural strength is found to be maximum at 10 wt% BV fiber content, indicating a strong interfacial bond between fiber and matrix as supported by scanning electron microscope of fracture surfaces of the composite. The impact strength and hardness of the BV/polypropylene (PP) composite increases with BV fiber loading. According to the dynamic mechanical analysis results, with rise in BV fiber content in the composite, the storage and loss modulus improved, but tan delta reduced. The thermogravimetric analysis and derivative thermogravimetry inferred that the composite's thermal stability lies between modified BV fiber and PP matrix. The differential scanning calorimetry curve studies the melting and crystallization behavior of the composite. The higher crystallinity index of composite is obtained at 10 wt% BV fiber content supported by tensile strength result. Both hot and cold‐water immersion processes studied the water absorption behavior of the composite. The composite with a higher percentage of fiber absorbs more water and takes less time to reach saturation. Compared to other produced composites and neat PP, it is observed that composites fabricated with 10% BV fiber content have superior characteristics. [ABSTRACT FROM AUTHOR]

This article deals with the development of polymer composites by incorporating carbon blacks (CBs) into polydimethylsiloxane (PDMS) matrix material for improving the mechanical and physical properties of the polymer composites. CBs of nano-size were used as filler material in varying volume percentages (5–25%), and the polymer composite was processed by solution casting method. Density, elastic modulus and hardness were measured in order to study the effect of the CB-reinforced PDMS matrix. Experimentally obtained mechanical properties were then compared with the standard empirical model. Density of the polymer composite was increased by five times as compared to the pure polymer material. With the increase in volume percentage of CB, both hardness and elastic modulus of the polymer composites were enhanced. Scanning electron microscope images of the composite material showed uniform distribution of CBs, implying strong binding with the matrix material, which attributed to improved mechanical properties. [ABSTRACT FROM AUTHOR]

The aluminium alloy will improve its strength further with addition of reinforcement on considering its applications to produce much lighter weight to high strength parts. This work examines the addition of silicon carbide at varying levels of 12%, 14% and 16% in 6061 aluminium alloy. In addition, magnesium and copper are added to aid the strength of the Aluminium Metal Matrix Composite. The process parameters are optimized for the wear rate of the composites through Taguchi technique together with design of experiments. The percentage of SiC addition, load applied (30N, 60N and 90N) and sliding distance (500m, 1000m and 1500m) are the parameters taken into consideration for this wear analysis. It was observed that sliding distance was the most influencing factor, among others, while investigating the wear behaviour with ANOVA. Microstructure analysis performed with a scanning electron microscope on worn surfaces shows that SiC particles influence the wear rate of the composites. [ABSTRACT FROM AUTHOR]

In this study, composite was made by the addition of 10 wt% SiC particles in the LM25 matrix through gravity casting and thixocasting processes. Thixocasting temperature was varied to investigate its effect on the microstructure, mechanical and thermal properties. Properties of thixocast samples were also compared with gravity cast ones. XRD analysis was done to analyse the phases present in the samples. Optical microscope and scanning electron microscope were used to record the microstructures of gravity cast as well as thixocast samples. Tensile, compressive and flexural tests were performed on universal testing machine with the prepared composite samples according to the ASTM standards. Thermal diffusivity tests of gravity cast and thixocast samples were done on laser flash diffusivity instrument. Results reveal that thixocast samples are sounder than the gravity cast samples. The microstructure of α-Al phase transformed from dendritic to globular shape due to the thixocasting. Also, volume fraction of eutectic phase in the sample increased with the increment of thixocast temperature. Tensile strength, compressive strength and flexural strength were found higher in the case of thixocast samples as compared to gravity cast. Thermal diffusivity considerably increased due to thixocasting, while its value slightly reduced with increment of thixocast temperature. [ABSTRACT FROM AUTHOR]

Due to the importance of rheology and morphology of microfibrillar reinforced composites (MFCs), a study has been conducted on MFCs based on high-density polyethylene (HDPE) and polyamide-6 (PA-6) using scanning electron microscope and dynamic rheometer. In the absence of an interfacial modifier and at 10 wt% concentration of the dispersed phase (PA-6), two principal factors, elongational deformation and coalescence, were found to be controlled by viscosity and elasticity ratios of the pure constituents accounting for the observed morphology of MFCs. The developed microfibrillar morphology remarkably influenced the viscoelastic properties of MFCs. It was observed that when the viscosity ratio approached unity and the elasticity ratio was minimal, the extent of coalescence in composite was significant. The rheological assessment showed enhanced storage modulus and complex viscosity upon microfibrils formation. This was more pronounced for samples with thinner microfibrils due to more strongly entangled network, compared to the composites with thicker microfibrils. The length-to-diameter ratio of the microfibrils could not be estimated due to their highly asymmetric length scale. [ABSTRACT FROM AUTHOR]

Mild steels are applied in the construction of oil platforms and pipelines due to their ease of formability, machinability, good mechanical properties, availability and low cost. However, they are still susceptible to corrosion attack and the cost implication of addressing failed components resulting from corrosion are enormous. The aim of this research was to deposit zinc–zinc oxide–nanocellulose (Zn–20gZnO–xCn) coatings on mild steel substrates for enhanced corrosion resistance. Corrosion study of the deposited coatings were done by weight loss corrosion method. X-ray diffractometer, scanning electron and optical microscopes were used to examine the surface morphologies and phase evolutions of the deposited coatings. The results showed that all the coatings recorded lower corrosion rates values than that of the substrate (mild steel) sample, with value 5.4392 mm/yr. Sample C3 (Zn–20gZnO–15gCn) had the lowest corrosion rate of 0.8201 mm/yr, translating to a protection efficiency of 85% on the substrate. Sample B1 (Zn–20gZnO–0gCn), gave the highest corrosion rate values among the coatings, of 2.0738 mm/yr., with protection efficiency values of 62% on the substrate. The study showed that the coatings were able to mitigate the corrosion attack from the media, thereby lowering the corrosion rates of the mild steel substrate. [ABSTRACT FROM AUTHOR]

The present work intended to investigate the effect of Dalbergia sissoo wood waste on physical, mechanical, and thermal properties of poly(lactic acid) (PLA)‐based composites. The composite specimens, containing wood waste (2.5%, 5%, 7.5%, and 10% by weight) mixed with PLA granules, were prepared by melt compounding. It was found that increased wood waste content resulted in higher modulus, porosity, and water absorption with decreased density, tensile strength, impact strength, and stress at break. Nevertheless, the flexural strength values of the composites were similar to unfilled PLA and they remained almost constant irrespective of the wood waste content. Differential scanning calorimetry analysis revealed that the presence of wood waste content increased the glass transition and cold crystallization temperature of the PLA composites. Moreover, the fractured surfaces of the composites were examined with a scanning electron microscope to study the possible failure mechanisms. The conducted investigations demonstrated that low‐cost wood waste‐based composites can be used as an environmentally and economically attractive substitute for lightweight applications. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide (rGO) nanosheets are functionalized with 2-methylimidazole (2-MI) to construct a high-efficiency corrosion resistant composite for waterborne polyacrylate coatings. The functional composites are confirmed structural and morphological investigation of sheets by Fourier transform infrared spectroscopy(FT-IR), Raman, x-ray diffraction(XRD), thermogravimetry(TGA), x-ray photoelectron spectroscopy(XPS), scanning electron microscope(SEM) and transmission electron microscopy (TEM) analysis. It is found from the electrochemical test results that after inclusion of 0.5 wt.% 2-MI/rGO nanoparticles incorporation into polyacrylate coatings, the Rct increased from 4.08E03 Ω.cm2 (for pure resin) to 4.02E05 Ω.cm2 in 3.5 wt.% NaCl solution, and the protective efficiency is up to 98.15% for carbon steel. The effective healing process can be concluded that the shield effect of rGO composites greatly extend the diffusion path of corrosion factor and blocked the electrolyte penetration and corrosion extension. [ABSTRACT FROM AUTHOR]

Magnesium alloys and composites, because of their notable properties, are currently being investigated to open out widespread applications for different industries. In this study, Mg–6Zn–1Ca alloy matrix composite, with different volume percentages of Al2O3 reinforcing particles, was produced by stir casting followed by hot extrusion. The microstructure of the cast and extruded alloys and composites was characterized using optical and scanning electron microscopes, energy-dispersive X-ray and X-ray diffraction spectroscopies. All produced samples were then undergone hardness and wear experiments. Microstructural observations indicated that Ca2Mg6Zn3 precipitates are often located at the grain boundaries of the α-Mg matrix. The observations also showed that increasing the amount of Al2O3 not only increases the hardness but also improves the wear resistance of both the cast and extruded samples, although wear resistance of the extruded composites was much higher than that of the cast samples. Besides, increasing the extrusion temperature from 350 °C to 400 °C increased the wear rate, and the composites extruded at 350 °C possessed the best wear resistance among samples. The results also showed that a combination of the abrasive, delamination and adhesive wear mechanisms takes place in composites, although abrasion is the predominant mechanism in the composites extruded at 350 °C. [ABSTRACT FROM AUTHOR]

This experimental study is conducted to investigate the effects of boric acid additive into polypropylene in terms of microstructure formation and thermal properties. Boric acid granules are added into pure polypropylene at three mass rates of 0.5, 1.5, and 2.5% which are notated as PP/BA-0.5, PP/BA-1.5, and PP/BA-2.5, respectively. The pure polypropylene material (pure PP) and boric acid reinforced polypropylene composite materials (PP/BA) are manufactured in an injection molding machine. The microstructure of composite materials is examined with an SEM (scanning electron microscope) device. Thermal analyses are conducted by using a TGA (thermogravimetric analyzer) device. In addition, thermal conductivities of composite materials are measured between 10 and 50 °C temperatures. SEM images show that boric acid at 0.5% additive rate forms a homogeneous composite by uniformly spreading the polymer chains, while boric acid at high additive rates of 1.5% and 2.5% becomes agglomerated within the polymer. TGA analyses show that the initial evaluation degradation temperature (Ti) tends to decrease with the addition of boric acid. Thermal conductivity for all examined materials almost linearly increases with temperature at a slope of about 0.0004 [(W m−1 K−1)/K]. Thermal conductivity is reversely proportional to the boric acid additive rate. The thermal conductivity for 2.5% boric acid added polypropylene is about 5% less than pure polypropylene. [ABSTRACT FROM AUTHOR]

A facile method has been developed to fabricate nano-encapsulated paraffin wax within silica shell (SNsPCM) by in-situ hydrolysis and polycondensation of silica precursor. SNsPCM composite was studied using field-effect scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), X-ray Diffractometry (XRD), Raman and Fourier transformation infrared spectroscopy (FT-IR), respectively. The results revealed the formation of spherical paraffin nano-structure encapsulated within the shell of SiO 2 with diameters ranging from 100 to 200 nm. Thermal stability, determined by differential scanning calorimeter (DSC), and thermogravimetric analyser (TGA), confirm the fabrication of a solid-solid and solid-liquid phase changing nanomaterial (PCnM). Simulations performed for thermal change within the paraffin core bounded by silica shell, for cycles of heating and cooling show excellent pressure durability of silica shell. PCnM behaviour studied using DSC measurement shows reversible fusion and solidification for repeated heating and cooling cycles. The SNsPCM composite with a paraffin encapsulation ratio of 79.89 wt% melted at 54.72 °C with a latent heat of 149.29 J/g and solidified at 52.09 °C with a latent heat of 100.16 J/g. The TGA results show improved thermal stability with an increased encapsulation ratio of PCnM by silica shell. SNsPCM can a potential material for thermal energy storage. Image 1 • Synthesis of core shell paraffin silica nanocomposite using In-situ hydrolysis and polycondensation process. • An insight towards the thermal properties of nano-encapsulated paraffin with silica shell using COMSOL simulation. • Determination of Von-mises stress and Volumetric strain along with Leakage test. • Thin film deposition of nano-encapsulated paraffin with silica shell using Langmuir Blodgett technique. • The fabricated thin film has been proposed for efficient thermal energy storage application. [ABSTRACT FROM AUTHOR]

Bio-composites, which can be obtained from the renewable natural resources, are fascinating material for use as sustainable biomaterials with essential properties like biodegradable, bio-compatibility as well cyto-compatibility etc. These properties are useful for bio-medical including wound healing applications. In this study, fibre obtained banana pseudo stem of banana plant, which is otherwise wasted, was used as a material along with chitosan and guar gum to fabricate a banana fibre-biopolymer composite patch. The physiochemical properties of the patches were examined using Fourier Transformed Infra-red spectrophotometer (FT-IR), tensile tester, Scanning Electron Microscope (SEM), contact angle tester, swelling and degradation studies. We further demonstrated that a herbal drug, Nirgundi could be loaded to the patch showed controlled its release at different pHs. The patch had good antibacterial property and supported proliferation of mouse fibroblast cells. The study thus indicates that banana fibre-chitosan-guar gum composite can be developed into an alternative wound healing material. [ABSTRACT FROM AUTHOR]

Triethanolamine (TEA) is a multifunctional organic additive, applied chiefly to a grinding aid and accelerator for cement. Its effect on cement paste in a sulfate-rich environment remains still unclear and elusive. In this paper, the expansion and mechanical performance of cement paste under external sulfate attack were measured. Thermodynamic model lent itself to estimate the correlation between triethanolamine and generated products content ahead of quantified phase analysis. The transformation of internal component was surveyed by multiple technologies of thermal gravimetric (TG), scanning electron microscope (SEM), X-ray diffraction (XRD), and nuclear magnetic resonance (NMR), while inductively coupled plasma (ICP) was applied to investigate the evolution of interstitial ion concentration. Furthermore, the changes of pore structure over immersion time were separately figured and tabulated by virtue of mercury intrusion porosimetry (MIP). The above analysis shows that when cement paste suffers sulfate attack, triethanolamine intensifies the formation of calcite and exacerbates the decalcification of C-S-H, promoting a large quantity of insoluble precipitation including mirabilite of abundant crystalline water which accounts essentially for severe damage. Determined after comprehensive evaluation, the addition of TEA is conducive to the emergence of physical sulfate attack and an increment of the total porosity and permeability, contributing to an extension of microcracks and a more fragile structure, ultimately makes cement paste appear as a reduction in strength and stiffness. • Triethanolamine correlates adversely with the resistance to sulfate attack of cement paste • The complex of sulfate and aluminum ions occupied by the TEA intensifies decalcification of C-S-H • Triethanolamine loosens internal structure and permeability paths inside cement paste within sulfate attack [ABSTRACT FROM AUTHOR]

• The novel Fe 3 O 4 /GON/CA-CDP composite was prepared. • The Fe 3 O 4 /GON/CA-CDP composite exhibited good MB adsorption ability and magnetism. • The MB adsorption of composite obeyed Sips model and intraparticle diffusion model. A novel composite basing on the Fe 3 O 4 nanoparticle, the graphite oxide nanosheet (GON), and the citric acid-crosslinked β-cyclodextrin polymer (CA-CDP) was prepared for the purpose of removing the methylene blue (MB) dye from water. The structure of the resultant Fe 3 O 4 /GON/CA-CDP composite was investigated by the scanning electron microscope, the two dimensional EDS mapping, the thermal gravimetric analyzer, the Fourier transform infrared spectroscope, the wide angle X-ray diffraction, the X-ray photoelectron spectroscope, and the zeta potential measurement. The Fe 3 O 4 /GON/CA-CDP composite not only had a good MB adsorption capacity of 173 mg/g but also a high saturation magnetization of 36.4 emu/g. It was found that the MB adsorption capacity of the Fe 3 O 4 /GON/CA-CDP composite increased with the increasing initial MB solution pH value especially in the low-pH-value range. Moreover, the MB adsorption mechanism, the MB adsorption isotherm, and the MB adsorption kinetic of the Fe 3 O 4 /GON/CA-CDP composite were investigated. It was found that 1) the good adsorption ability of the Fe 3 O 4 /GON/CA-CDP composite for the MB dye originated from the electrostatic attraction, the Lewis acid-Lewis base interaction, the host-guest supramolecular interaction and the π-π interaction, and 2) the MB adsorption isotherm and the MB adsorption kinetic of the Fe 3 O 4 /GON/CA-CDP composite could be well explained by the Sips model and the intraparticle diffusion model, correspondingly. [ABSTRACT FROM AUTHOR]

Constructing a hierarchical structure of nanomaterials on the surface of reinforcing fibers is the best strategy to obtain other desired functions while improving the mechanical properties of polymers. In this article, acid-treated multiwall carbon nanotubes (MWCNTs) were introduced to the surface of milled glass fiber (MGF) under the combined action of tetraethyl orthosilicate and 3-aminopropyltriethyloxysilane to prepare a hierarchical fiber (MWCNTs-GF). The surface morphology and microstructure of this hierarchical fiber were characterized by field-emission scanning electron microscope and transmission electron microscope, and a composite coating with MWCNTs as the main component was observed on each fiber surface. Fourier transform infrared and Raman spectroscopy revealed the presence of the specific interactions between MWCNTs and MGF. Polyamide 66 (PA66) composites with different content of MWCNTs-GF were fabricated by melt blending. The resulting composites exhibited improved mechanical properties relative to pure PA66, in which the tensile strength and notched impact strength of the composite filled with 3 wt% MWCNTs-GF increased by 23.3% and 69.0%, respectively. Subsequently, by analyzing fracture morphology and interfacial adhesion of the composites, the strengthening and toughening mechanisms of MWCNTs-GF were elaborated in detail. In addition, the results of thermogravimetric analysis and differential scanning calorimetry showed that MWCNTs-GF possessed strong heterogeneous nucleation ability, and its addition could refine the grain size of PA66 and significantly increase the crystallization temperature and thermal stability of the corresponding composites. Compared to PA66 composites reinforced with neat MGF, it was found that the unique surface structure of MWCNTs-GF was likely responsible for improved thermal properties of this hierarchical fiber-reinforced PA66 composites. [ABSTRACT FROM AUTHOR]

In this work, biopolymer hydrogels were synthesized by mixing hyaluronic acid, hydrolyzed collagen, and chitosan through a solvent evaporation method and incorporating them with caffeic acid as an antioxidant agent. The obtained caffeic acid-loaded chitosan/hydrolyzed collagen/hyaluronic acid hydrogels were characterized by X-ray diffraction, differential scanning calorimetry and thermogravimetric analysis. No significant change on structural and thermal properties was observed. Furthermore, scanning electron microscope reported that the surface morphology of the hydrogels was smooth, and no significant change in porosity was observed after the addition of hyaluronic acid. With high amount of hyaluronic acid, the swelling behaviour was superiority. The hydrogels showed an initial burst release of caffeic acid (~70%) within 60 min, followed by a gradual release of up to 80% by 480 min. The release was slightly higher with the presence of hyaluronic acid. In addition, DPPH , ABTS +, and FRAP assays revealed that the caffeic acid-loaded hyaluronic acid/hydrolyzed collagen/chitosan hydrogels exhibited antioxidant activity. Thus, these composites could potentially be used as dressing materials with antioxidant activity. [ABSTRACT FROM AUTHOR]

In situ composites are today being considered for industrial use, owing to the fewer production steps involved, lower production cost, and better wetting of reinforcements. This study emphasises the characteristic features of an Al–Mg2Si–Cu in situ composite, with the addition of different amounts of Sr (0.01–0.1 mass%) as a modifier reagent, by employing computer-aided cooling curve thermal analysis. The identification of microstructures and phases was carried out using a scanning electron microscope equipped with an energy dispersive spectrometer. The results show that the nucleation temperature of the primary Mg2Si, eutectic Mg2Si, and Al5FeSi phases initially increased with the addition of 0.01 mass% Sr, and subsequently decreased with further addition of the element. Two new Sr-containing phases were detected after the precipitation of primary Mg2Si phase and prior to the formation of eutectic Mg2Si phase. A relationship between the cooling rate (CR) and solidification rate (SR) was established. Based on cell coherency point, it was found that the eutectic Al–Mg2Si cell required a longer time to grow with the increment of Sr. The solid fraction of Al5FeSi and Al5Cu2Mg8Si6 + Al2Cu phases remained constant at 8 ± 1% and 3 ± 1%, respectively. The increase in the terminal freezing range and the cracking susceptibility coefficient, by 182% and 16%, respectively, shows that Sr increases the probability of hot tearing. [ABSTRACT FROM AUTHOR]

Research on hydrogels as soil conditioners has been developed based on hydrogels copolymerized with composite materials in the form of chitosan and TiO2 to overcome low physical properties and low swelling of polyacrylamide. The aims of the study are synthesis, characterization, application of hydrogels, and determination of the physical and chemical properties of soil and the growth of soybean plants. Synthesis of chitosan-co-polyacrylamide-TiO2 crosslinked glutaraldehyde hydrogel was prepared by the chemical crosslinking method. The characterization of hydrogel was performed by using Fourier Transform Infra-Red (FTIR) and Scanning Electron Microscope (SEM). FTIR spectrum shows the functional groups of chitosan co-polyacrylamide-TiO2 crosslinked glutaraldehyde which includes OH functional groups (3408.22 cm-1), NH (1602.85 cm-1), C=O (1502 cm-1), CN (1600.92 cm-1), and Ti-O (619.15 cm-1). The SEM image shows the formation of pores and cavities in the hydrogel. The application of hydrogels in soybean plants shows differences in physical and chemical properties of soil and plant growth. The use of all variations of hydrogel had no significant effect on soil physical properties including temperature, humidity, and bulk density. Meanwhile, hydrogels with TiO2 concentration of 60 ppm influence significantly to the chemical properties of soil such as organic carbon, cation exchange capacity (CEC), and level of nitrogen, phosphorus, and potassium in the soil. The optimum number of leaves, plant height, total dry weight are 68 leave blades, 207 cm, and 20.6 g, respectively. This optimum condition was found in the use of KTiKPAG60 hydrogel. The results showed that chitosan-co-polyacrylamide-TiO2 crosslinked glutaraldehyde has the potential to be a soil conditioner. [ABSTRACT FROM AUTHOR]

Demands on better control over the kerf dimension deviation, surface roughness, and corner accuracy are now on the increase for the two-piece aluminum metal composite mold tools. In this investigation, straight and triangular profile cuts attempted with wire electrical discharge machining (WEDM) on the aluminum 6061 self-lubricating composite-reinforced boron carbide (5–15 vol%) and hexagonal boron nitride particles (10 vol% hBN) fabricated using a stir casting method. Rational video measurement showed an increase in B4C particles reduces kerf width dimension deviation only at TON, TOFF and gap voltage (V) parameters. Optical microscope measurement showed an increase in the corner area inaccuracy increases with both low and high pulse-on duration conditions caused by insufficient material removal and a high order of erosion, respectively. There was a large reduction in corner area inaccuracy with increasing wire feed rate. Surface characteristics were examined using a scanning electron microscope (SEM) and XRD to enable observation of the structural damages and recast layers. Composite with 5% boron carbide showed a re-deposition layer over the machined surface, whereas 15% boron carbide composite went through uneven erosion causing the formation of craters and pits on the cutting surface resulting in higher surface roughness. [ABSTRACT FROM AUTHOR]

The advanced multifunctional filler has become one of the main challenges in developing high-performance polymer composites. In this study, the acid-treated multiwall carbon nanotubes (MWCNTs) were adhered to the surface of milled glass fiber under the combined effect of 3-aminopropyltriethyloxy silane and tetraethyl orthosilicate to fabricate a hierarchical fiber (MWCNTs-MGF). The morphologies of the hierarchical fibers were characterized using field-emission scanning electron microscope and transmission electron microscope, which showed evidence of a coating layer of MWCNTs on each fiber surface. The MWCNTs-MGF was employed as a multifunctional filler to prepare polyoxymethylene-based composites using a twin-screw extruder by melt blending. The obtained composites exhibited improved mechanical and thermal properties. The composite tensile strength and notched impact strength and Young's modulus increased by 10%, 32%, and 32%, respectively, as the MWCNTs-MGF content varies from 0 to 10 wt.%. Meanwhile, the reinforcing and toughing mechanisms of MWCNTs-MGF were also elaborated by analyzing the interfacial adhesion and fracture morphologies of the composites. Moreover, the study on thermal stability and crystallization behavior indicated that the polyoxymethylene/MWCNTs-MGF composites had higher thermal stability, crystallization temperature, and crystallinity as compared to the polymer matrix. The improvement of thermal stability originates from the unique surface structure of MWCNTs-MGF, while the increase in crystallization temperature and crystallinity is due to the strong heterogeneous nucleation ability of the hierarchical fibers. [ABSTRACT FROM AUTHOR]

The bast fibres, a subgroup of natural fibre family, have emerged as a strong competitor of widely used man-made glass fibre for use as fillers or reinforcing materials in certain types of composite materials, which do not require very high mechanical resistance. This paper investigates the manufacturing of multi-layered jute fabric-reinforced thermoplastic composite and its mechanical performance. Hessian jute fabrics in two, four and six layers without any pre-treatment were sandwiched in 0° orientation into seven layers of high-density polyethylene sheets and pressed at high temperature and pressure to form composite laminates having three different structural designs. The laminates with two, four and six layers contain approximately 6.70 wt%, 12.90 wt% and 18.50 wt% of jute fibres, respectively. Mechanical performance of the composite laminates having four and six layers of jute fabric was found to have improved significantly when compared to the pure high-density polyethylene laminates. Within a given sample thickness of 6.5 mm, the laminate with six layers of jute fabric exhibited the best mechanical performance. Optical microscopic analysis revealed that the yarn orientation of the fabrics within the composites remained stable, and there was no visible void in the laminate structure. Fracture morphology of the composite investigated by a scanning electron microscope showed good adhesion of the jute fabrics with the high-density polyethylene matrix. [ABSTRACT FROM AUTHOR]

This report describes progress in the development of cellulose hydrogel by blending with natural rubber (NR). Cellulose regenerated from the bagasse sugarcane was used for this study. Although cellulose and NR have a considerably low mutual affinity, composite hydrogels with various cellulose and NR contents were prepared using a wet-phase inversion method. The maximum amount of NR that can be loaded into the cellulose hydrogel was about 30% vol. Once NR is introduced into the cellulose hydrogels, the obtained hydrogel became translucent and eventually opaque with increasing NR loading. Measurements of water absorption, the water contact angle, and evaluation of fourier-transform infrared spectroscopoy (FTIR) spectra revealed that the presence of NR decreases the water affinity of the hydrogels. Nevertheless, it is noteworthy that the composite hydrogels had higher tensile strength and better elastic properties than the pristine hydrogel. The results showed that the obtained composite hydrogels can be elongated several times to their original length. The enhancement of both properties was proportional to the amount of NR included. Results of scanning electron microscope (SEM) images showed NR present inside the hollow of the cellulose hydrogel, forming interconnected domains. One can infer that the increase of mechanical and elastic properties is attributable to the presence of these interconnected structures. [ABSTRACT FROM AUTHOR]

A novel N−TiO2/C/attapulgite (N−TiO2/C/ATP) composite photocatalyst was prepared by sol‐gel method using ATP supported o‐phenanthroline modified TiO2. The as‐prepared samples were characterized by X‐ray diffraction (XRD), fourier transform infrared (FT‐IR), X‐ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), ultraviolet‐visible diffuse reflectance spectroscopy (UV‐vis DRS) and N2 adsorption–desorption measurements. The activity of these photocatalysts was tested by degrading polyacrylamide (PAM) under visible light irradiation while N−TiO2/C/ATP shows significant photocatalytic enhancement compared to pure TiO2. The optimal ratio of N−TiO2/C/ATP photocatalyst is n (TiO2): n (o‐phenanthroline)=20 : 1 and the m (N−TiO2/C): m (ATP)=1 : 1. When the initial concentration of PAM is 300 mg/L and the catalyst dosage is 1.5 g/L, the removal rate of chemical oxygen demand (COD) reaches 86.3 % at pH 2 under 2 h of visible light. The enhanced performance can be attributed to the C element in o‐phenanthroline is modified on the TiO2 surface as a surface sensitizer and the N element may enter anatase TiO2 lattice and replace to form O−Ti−N bond. Meanwhile, some TiO2 particles were permeated into the layer of ATP, which made the composite photocatalyst more stable and the N−TiO2/C/ATP composite exhibits good stability after three times recycling. In addition, the possible photocatalytic mechanism is proposed at the end. [ABSTRACT FROM AUTHOR]

The electroless nickel phosphorus (EN) composite coatings, containing different weight percentages of Nylon 6,6 particles, were prepared using electroless baths that vary with the concentration of Nylon ranging from 0 to 10 g/L. The distribution of Nylon particles in the EN .matrix was analyzed using scanning electron microscope – energy dispersive spectroscopy. The wear resistance of the EN Nylon composite coating was better than that of the EN coating. The composite coating that was prepared, using a bath containing 6 g/L of Nylon, shows the best combination of hardness and wear resistance. [ABSTRACT FROM AUTHOR]

In this study, Ce 0.8 Er 0.2 O 2-α was prepared via a microemulsion method. Then, Ce 0.8 Er 0.2 O 2-α powder was mixed with melted NaCl-KCl (1:1 mol ratio) at the weight ratio of 80%: 20% to obtain Ce 0.8 Er 0.2 O 2-α -KCl-NaCl at 750 °C. Ce 0.8 Er 0.2 O 2-α and Ce 0.8 Er 0.2 O 2-α -KCl-NaCl were characterized by thermogravimetry analysis and differential scanning calorimetry (TGA-DSC), Raman spectrometer, X-ray diffraction (XRD) and scanning electron microscope (SEM). The log (σT) ~ 1000 T-1 plots and fuel cell performances of Ce 0.8 Er 0.2 O 2-α and Ce 0.8 Er 0.2 O 2-α -KCl-NaCl were tested at 400–700 °C. The maximum output power density of Ce 0.8 Er 0.2 O 2-α -KCl-NaCl was 187 mW cm-2 at 700 °C which is six times greater than that of Ce 0.8 Er 0.2 O 2-α. [ABSTRACT FROM AUTHOR]

To overcome the limitations of a singular fibre-reinforcement composite, a number of hybrid composites have been developed consisting of two or more different types of fibres in a common matrix. With the correct combination of dissimilar fibres, a variation of hybrid composite can be obtained possessing improved physical and thermal properties which is previously not possible with a single kind of reinforcement. The use of powerful lasers (several kW) in the cutting of composites is fairly widespread so as to overcome challenges regarding the anisotropic properties of these materials, but at the expense of a large heat affected zone (HAZ), kerf width, and fibre pull-out. The primary aim of this paper is to investigate low-power CO2 laser cutting of a carbon/Kevlar fibre-reinforced hybrid composite. Response surface methodology (RSM) along with Box-Behnken design (BBD) was employed to understand the interactions between the process parameters, such as laser power, cutting speed and standoff distance (SOD), and their effects on the cut quality characteristics including size of the HAZ and kerf characteristics. Following this, process parameter optimization was successfully carried out using ANOVA to minimize the HAZ and kerf width. Qualitative measurement using a scanning electron microscope (SEM) was performed to evaluate the effects of process parameters and fibre orientation on fibre pull-out, HAZ and material decomposition. Difference between the thermal properties of carbon fibres, Kevlar fibres and polymer matrix (epoxy) was found to influence HAZ and kerf width. High thermal conductivity of carbon fibres particularly led to large extent of matrix recession and burning of Kevlar fibres around the cut path. [ABSTRACT FROM AUTHOR]

It is a challenge to synthesize metal‐organic frameworks (MOFs) catalysts with high catalytic activity and stability under reaction conditions. For this study, the combinations of two‐dimensional (2D) ultrathin nickel‐organic framework (Ni‐UMOF) with layered graphitic carbon nitride (g‐C3N4) or graphene oxide (GO) as promising composite catalysts for the hydrogenation of 4‐nitrophenol were reported. The ultrathin nanosheet composites (Ni‐UMOF/g‐C3N4 and Ni‐UMOF/GO) are obtained by a simple sol‐gel method and exhibit higher hydrogenation activity and recyclability than commercial Pd/C or Pt/C catalysts. The structures and properties of the catalysts are elucidated by X‐ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), atomic force microscope (AFM), fourier transform infrared spectra (FT‐IR), Raman, ultraviolet–visible spectroscopy (UV‐Vis), X‐ray photoelectron spectroscopy (XPS), electron spin‐resonance spectroscopy (ESR) and temperature‐programmed reduction (TPR). The results reveal that oxygen vacancies are produced on the surface of Ni‐UMOF composites and act as the dominating active sites during hydrogenation process. This sol‐gel method can be applied to synthesize other 2D ultrathin MOFs composites with high catalytic activities and recyclability for redox reactions. [ABSTRACT FROM AUTHOR]

We report the effect of graphene (G) allotropic carbon modification in a content range of 0.5–2.0 wt % on the tribological, strength, and structural characteristics of an Al2O3/G nanocomposite produced by a 10-min plasma spark sintering (at a pressure of 50 MPa and a temperature of 1550°C) of a nanopowder mixture, previously subjected to ultrasonic dispersion in organic solvent. Its lubricant free friction and wear are tested at room temperature on a tribometer under a load of 20 N, at a roundabout motion of a ruby ball penetrator on a disk. The nanohardness and elastic modulus of the nanocomposite are determined via kinetic indentation. The fracture surface structure and friction track are monitored using a scanning electron microscope. The microstructure in the bulk of the nanocomposite was probed via dark- and bright-field transmission electron microscopy scanning of thin foils. The thermal stability of graphene was monitored via Raman spectroscopy. The introduction of graphene is shown to improve micro- and nanohardness, elasticity, and wear resistance by two to three orders of magnitude, as well as to slightly decrease the coefficient of friction. A graphene content of 2 wt % alters the mechanism of wear from brittle fracture to viscous shear owing to stronger coupling of matrix grains and the presence of agglomerates. A lack of degradation and the retention of graphene thermal stability are evidenced as well. The morphology of graphene particles reveals their preferential arrangement inside the corundum grains rather than at the grain boundaries. [ABSTRACT FROM AUTHOR]

Purpose: Aluminium and its alloys are the most preferred material in aerospace and automotive industries because of their high strength-to-weight ratio. However, these alloys are found to be low wear resistance. Hence, the incorporation of ceramic particles with the aluminium alloy may be enhanced the mechanical and tribological properties. The purpose of this study is to optimize the specific wear rate and friction coefficient of titanium dioxide (TiO2) reinforced AA7075 matrix composites. The four wear control factors are considered, i.e. reinforcement (Wt.%), applied load (N), sliding velocity (m/s) and sliding distance (m). Design/methodology/approach: The composites were fabricated through stir casting route with varying weight percentages (0, 5, 10 and 15 Wt.%) of TiO2 particulates. The mechanical properties of the composites were studied. The specific wear rate and friction coefficient of the newly prepared composites was determined by using a pin-on-disc apparatus under dry sliding conditions. Experiments were planned as per Taguchi's L16 orthogonal design. Signal-to-noise ratio analysis was used to find the optimal combination of parameters. Findings: The mechanical properties such as yield strength, tensile strength and hardness of the composites significantly improved with the addition of TiO2 particles. The analysis of variance result shows that the applied load and reinforcement Wt.% are the most influencing parameters on specific wear rate and friction coefficient during dry sliding conditions. The scanning electron microscope morphology of the worn surface shows that TiO2 particles protect the matrix from more removal of material at all conditions. Originality/value: This paper provides a solution for optimal parameters on specific wear rate and friction coefficient of aluminium matrix composites (AMCs) using Taguchi methodology. The obtained results are useful in improving the wear resistance of the AA7075-TiO2 composites. [ABSTRACT FROM AUTHOR]