Search

In this article, maleic anhydride (MA) was used to graft-modify chitosan (CS) to obtain maleic anhydride-modified chitosan (MCS). Composite films with different ratios were prepared by melt blending-extrusion pelletizing-blown film using Poly (butylene adipate-co-terephthalate) (PBAT) as the substrate and CS or MCS as the filler. These films can be utilized in a variety of ways, such as food packaging, agricultural mulching film, and more. The composite films were characterized and tested by a Fourier transform infrared (FTIR) spectrometer, thermogravimetric (TG) analysis, differential scanning calorimetry (DSC), scanning electron microscope (SEM), and electronic universal testing machine, and the effects of different fillers and filler contents on the properties of the composite films were investigated. The results showed that the thermal stability of the composite films decreased slightly with the increase in filler ratio, the melt crystallization temperature increased and then decreased, and the tensile strength and elongation at break of the composite films decreased. Compared with unmodified CS, MCS had better dispersion and compatibility when blended with PBAT, and the interaction between MCS and PBAT was greater than that of CS. The optimal filler amount of MCS was 6% for the combination of film material cost and performance considerations. [ABSTRACT FROM AUTHOR]

Natural fibre reinforced polymer composites have found a wide range of applications in the automobile industry, construction industry and toy industry, and so on. In this research work, bidirectional aloe vera fibre mats were used as reinforcement and epoxy as matrix materials. Hand Layup process was applied for fabrication of aloe vera fibre reinforced epoxy matrix composites which contain different fibre orientations such as 45°, 60°, 75°, and 0°/90°. The goal of this research work is to obtain the influence of fibre orientation on mechanical and water absorption properties. The experimental investigations like tensile strength, flexural strength, impact strength, and the water absorption tests were performed. The surface morphology of the tensile failed test specimens were alsoanalysed using afield emission scanning electron microscope (FE-SEM). When compared to other fibre orientation composites, 0°/90° aloe vera fibre orientation has superior mechanical capabilities and 45° fibre orientation obtained minimum mechanical properties, according to the results of the experiment. As compared to 45° fibre orientation, 90° fibre orientation obtained 283.81%, 168.41%, and 202.54% higher tensile, flexural, and impact strength, respectively. [ABSTRACT FROM AUTHOR]

Due to the high demand for cement-based materials in buildings, graphene has been widely studied as a potential new cement composite reinforcement agent. In this study, polycarboxylate (PC) Superplasticizer, Tetraoxatetradecan-1-ol,14-(nonylphenoxy)-(CO520), Sodium dodecyl-benzenesulfonate (SDBS), Sodium cholate (SC), and Hexadecyl trimethyl ammonium Bromide (CTAB) were used as surface-active agents (SAA). The effects of different graphene contents (0, 0.01%, 0.03%, 0.05%, and 0.07%) on the mechanical properties were experimentally evaluated and analyzed. The results showed that under the same curing condition, when the graphene content is 0.03% (PC as SAA), the mechanical properties arrived at maximum. Compared with the control group, the compressive strength with 3, 14, and 28 curing days, achieved the improvement of 23.49%, 28.75%, and 33.99%, respectively. The flexural strength had the improvement of 22.18%, 25.11%, and 27.18%, respectively. The Scanning electron microscope (SEM), Diffraction of X-rays (XRD), Ultraviolet-visible Spectrophotometer (UV), Energy Dispersive Spectroscopy (EDS) and Raman analysis proved that graphene promoted the hydration reaction, and it played a filling effect and template role in the mortar matrix. Ultimately, when graphene content is within the appropriate range, the filling effect and the unplugging effect of graphene can effectively improve the performance of the mortar. [ABSTRACT FROM AUTHOR]

In the microwave (MW) pre-treatment process, a constant MW energy intensity of 2158 MJ/m3 was applied by using 925 W (3700 sec.), 1295 W (2640 sec.) and 1850 W (1850 sec.) powers. Tanalith-E preservative material was used to determine the increase in impregnability of MW pre-treated wood. The mechanical properties of the treated wood specimens were tested to determine the degradation caused by exposure to the MW radiation. Additionally, scanning electron microscope (SEM) was used to determine the changes in wood microstructure with the effect of microwave pre-treatment. According to the impregnations, the average preservative material retention rates increased 62% for the specimens with MW groups, compared to the reference specimens. The mechanical properties of the MW pre-treated specimens decreased by (average) 5% in compression strength, 12% in the bending strength and 16% in the modulus of elasticity. SEM observations of the reference specimens showed that there were many aspirated bordered pits before MW pre-treatment. After the MW pre-treatment, parts of the pit membranes were damaged. The torus ruptured and cracked, while the structure of the micro-fibrils on the margo remained intact. In the observations of the intercellular microstructure of wood, it was observed that micro cracks with a width of 1–10 μm were formed. [ABSTRACT FROM AUTHOR]

This paper aims to present compressive stress-strain behaviour and develop relationships for peak stress, strain at peak stress, and material parameter with the modified reinforcing index for analytical modelling of basalt fiber reinforced concretes (BFRC's) stress-strain curves. For this, three different strengths of BFRCs were developed i.e., normal-strength-BFRC, medium-strength-BFRC and high-strength-BFRC, each strength of BFRCs contains 0%, 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% of basalt fibers (BFs). The effect of BFs on mechanical properties, compressive stress-strain behaviour of the BFRCs mixes were studied experimentally. The energy absorption capacity, peak stress, and strain at peak stress of BFRCs have also been studied analytically. Scanning electron microscope analysis was performed to examine microstructural characteristics of BFRCs. The test results indicated that the maximum compressive, flexural, and split tensile strengths and better stress-strain behaviour exhibited at the addition of 0.3% of BFs in all three strengths of BFRCs. Using developed relationships, analytically modelled stress-strain curves closely represented the realistic stress-strain behaviour of BFRCs and fit well with the experimental stress-strain curves. In addition, in literature, the proposed expressions between the material parameter and reinforcing index for analytical modelling of steel FRC's stress-strain curves could not accurately predict the experimental stress-strain curves of BFRCs. [ABSTRACT FROM AUTHOR]

This paper focuses on the effect of yarn diameter, the density of yarn, woven type, Gram per Square Metre (GSM) and weight fraction fibre on tensile, flexural and impact properties of weaved sisal composite. Various types of woven fabrics were prepared from sisal fibres, and these fabrics are used to prepare the composites of variable weight fraction (Wff) as 20, 40, 50 and 60 percent by maintaining proper alignment of warp and weft direction. The tensile, flexural, and impact properties were found to increase with Wff content in all types of woven pattern composites. Plain 1 (P1) shows better mechanical properties as compared to Plain 2 (P2) and Plain 3 (P3)-based composites, and this shows GSM has a higher significance on mechanical properties. Further, the influence of woven pattern was analysed and found that the plain woven exhibits better tensile strength, but the herringbone exhibits better flexural and impact strength. Scanning Electron Microscope evidenced that good interfacial bonding between fibre and matrix interface. [ABSTRACT FROM AUTHOR]

The acrylic acid treated rattan fiber reinforced epoxy (RF/Epoxy) composite has been fabricated by taking various weight percentages (5, 10, 15, 20, and 25 wt%) of fibers using hand layup followed by compression molding technique. The optimum fiber loading has been determined by regression analysis and it is found that 18 wt% of rattan fiber gives maximum tensile strength. The interaction of rattan fiber with epoxy matrix has been studied by Fourier transform infrared spectroscopy and X-ray diffraction. Scanning electron microscope (SEM) has been used to study the morphology of chemically modified rattan fiber and RF/Epoxy composite. The mechanical, thermal, and dynamic mechanical thermal properties of 18 wt% RF/Epoxy composite have been studied as per ASTM standards. From the results, it is observed that RF/Epoxy composite gives best properties at optimum (18 wt %) fiber loading. The maximum tensile strength and flexural strength of the composite are found to be 47.5 and 121 MPa, respectively, which is better in comparison to other natural fiber composites used for manufacturing different automobile body parts. Hence, it can be concluded that 18 wt% RF/Epoxy composite can be considered as a potential candidate for automotive body parts. [ABSTRACT FROM AUTHOR]

The aim of the effort is to estimate the effect of jute and bamboo fibers with silica fume (SF) of different proportions on mechanical properties of concrete. Cube, cylinder and prism specimens are tested to determine the compressive, split tensile and flexural strength at 14 and 28 days of curing. To verify the experimental findings, further Artificial Neural Network (ANN) analysis is conducted. The study employs neural network (NN), such as the Neural Network-Leven Berg–Marquardt and the Neural Network Gradient Descent. In this investigation, feed-ahead lower back promulgation neural networks were employed. The NN predicted values are validated with actual values and the variation is found to be within 10% only. The predicted ANN results are compared with existing Response Surface Methodology model. Under compressive, split tensile and flexural load, the broken surface is examined at a smaller-scale level with a scanning electron microscope (SEM). The experimental results show that concrete with 0.5% bamboo fibers and 0.5% jute fibers with 10% SF had higher influence on the mechanical properties of concrete. When comparing ANN results, the suggested ANN model showed high level of accuracy in estimating the mechanical properties of natural-fiber-reinforced concrete. SEM examination displayed the failure pattern of concrete and fibers. [ABSTRACT FROM AUTHOR]

Nanoparticle incorporation in polymeric matrices to generate polymer nanocomposite with the intention of maximizing the "nano-effect" derived from the nanoparticles and minimizing the drawbacks of the polymer is an emerging field of research. In this study, low-density polyethylene (LDPE) was mixed with varying concentrations of montmorillonite (MMT) nanoclays to create a polymer nanocomposite with desirable characteristics. Composite sheets with nanoclays contents of (0, 1, 2, 3, and 4 wt%) were prepared for hardness, tensile-fractography, thermal conductivity, and tensile testing (elongation and stress-at-break). The results showed that, according to scanning electron microscope (SEM) study, LDPE has a low flexibility temperature and is prone to corrosion. For larger MMT filler loadings (>3% wt), tensile-fractography showed nanoclays particle micro-aggregation. The pure LDPE sample fracture's tensile-fractography showed plastic deformation. MMT/LDPE samples with 3% wt hard MMT filler have brittle fractures without appreciable plastic deformation. Thermal conductivity test results show that LDPE/MMT composite thermal conductivity decreased with increasing clay concentration. The thermal conductivity values were reduced from a value of 0.13 W/m.K to a value of 0.039 W/m.K when reinforced with 0% wt to 3% wt filler loading, respectively. With 4% wt filler loading, LDPE/MMT composites had the highest shore hardness at 47.4. Yet, tensile tests indicated that increasing clay content improved the composite's characteristics. At modest loading percentages (1-2 wt%), tensile results were excellent. Furthermore, the elongation at break of the unadulterated LDPE was reduced by 20% and 30% after introducing 1% wt and 2% wt of MMT as reinforcement additives, respectively. Hence, MMT clay can improve the mechanical properties and thermal insulation of LDPE polymer matrix. [ABSTRACT FROM AUTHOR]

This study is intended to improve the methodology to calculate the tensile properties of natural coconut fiber and increasing confidence in the use of sustainable natural fibers as reinforcing in composites used for different components in the naval industry. Coconut fiber is an agribusiness by-product that has been shown to have the potential for the development of new materials. The morphology of different species of coconut fiber was studied, and their mechanical tensile properties were determined. The coconut fibers were tested under direct tension in a universal testing machine, and the cross-sectional area of the fibers was calculated using images obtained in an optical microscope and a scanning electron microscope. The study assessed the incidence of key factors to determine coconut fiber mechanical tensile properties including different area measuring methods and the percentage of lumens present through an image analysis software called ImageJ. The results indicate that coconut fiber has a round-shaped cross-section, and the percentage of lumens is between 15% and 27%. Therefore, the effective area is reduced increasing the fiber's ultimate resistance to tension. [ABSTRACT FROM AUTHOR]

The mechanical behavior of banana fiber (BA) reinforced polymer composites filled with fly ash (FA) is analyzed in this present investigation. Polyester matrix is used to produce composites with 30% of banana fiber volume and fly ash with three separate volume fractions (1%, 3% & 5%). The failure mechanisms were identified through a scanning electron microscope using the fractured surfaces of the specimen after mechanical testing. The addition of 3% vol of fly ash results in an increase in the tensile, flexural, and impact strength of 46.3%, 24%, and 88.4% when compared with the banana fiber composites without fly ash (BAP). 5% vol of higher fly ash addition indicates a drop in the tensile, flexural, and impact properties of approximately 31.4%, 9.38%, and 30.61% when compared to 3% vol of fly ash added composites, respectively. Owing to weak interfacial bonding caused by the agglomeration of fillers, the higher filler loading results in subdued mechanical properties. With the help of SEM fractography, the parameters, including poor interfacial adhesion, defective surfaces, and fractures, were described. [ABSTRACT FROM AUTHOR]

In the present research, our aim is to study effects of alfa fiber content, alkali, maleic anhydride grafted polypropylene (MAPP), and the combined treatment (alkali and MAPP) on the tensile and flexural behavior of alfa fiber-reinforced polypropylene (PP) composites. These composites were produced using a single-screw extruder followed by an injection molding process. Both fibers and composites were characterized using optical and SEM microscope in order to evaluate the interfacial adhesion between the fibers and the matrix. From the main results, the tensile modulus and flexural strength of 30% untreated Alfa fiber/PP composites were found to increase significantly compared to those of PP. Meanwhile, there is no significant increase in terms of the tensile strength and the flexural modulus. Moreover, the composites with a combined treatment have shown significant effect on the tensile and flexural properties compared to untreated composites and the treated ones. The SEM observation of the morphology of alkali treated fibers exhibited an increase in the surface roughness because the removal of impurities. In addition, SEM photos of the fractured surface of composites reveal the improvement of the fibers and PP matrix interface quality by treatments, in particular the combined treatment. [ABSTRACT FROM AUTHOR]

The main goal of this study is to assess the mechanical, physical and morphological properties of bundle fibers extracted from curaua leaves and pullout testing in cementitious matrix. The mechanical properties of the fibers were analyzed in mechanical testing of four fiber lengths (10, 20, 30 and 40 mm) to observe the influence of the length of the variable's tensile strength, Young's modulus and Weibull modulus. Pullout testing was measured frictional and maximal force. Fibers physical properties were assessed by means of the multipycnometer method. Morphological analyses were conducted through optical and scanning electron microscopes. The results showed that the fiber length does not interfere with the tensile strength (507–638 MPa) and Weilbull modulus (8–12). However, it influences the Young's modulus (19–39 GPa). Curaua bundles present a higher resistance to rupture and Young's modulus than other plant fibers species and it seems to be related to the distribution of faults along the beam. The fibers morphological characterization showed a rough and irregular surface with some impurities which are associated with the surface of the fibrous bundle and low adherence (0,26–0,47 N) with cementitious matrix in pullout testing. [ABSTRACT FROM AUTHOR]

The study deals with the mechanical and thermal characterization of novel composite consisting of vetiver grass fiber (Chrysopogon zizanioides) (VF) and red mud (RM) as reinforcement in epoxy resin. Five types of composites were fabricated using hand lay-up technique by varying the weight percentage (wt%) of vetiver grass and red mud. Various mechanical properties like tensile strength, impact strength, and flexural strength of the said composites were evaluated and discussed. The thermal properties in terms of thermo gravimetric analysis (TGA) were evaluated whereas the chemical composition characteristics were analyzed using FTIR and XRD spectroscopy. The fractured surfaces of the tested specimens were studied using a scanning electron microscope. From the results, it was observed that properties of polymer composites were improved by hybridization with vetiver grass fibers and red mud. The improved mechanical properties of fiber-reinforced composites were noticed in increment of wt% of red mud. Highest tensile strength of 51.78 MPa, flexural strength of 35.92 MPa and impact strength of 29 KJ/m2 was obtained for C5 composite which contains highest wt% of red mud. TGA shows better resistance to thermal degradation for the composites containing higher percentage of red mud. Looking at the results it can be concluded that the developed composites in this work can be an efficient alternative for building and automotive application which requires high strength and thermal stability. [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]

The structure and mechanical properties of non-equiatomic Al8Co30Cr18Fe9Ni31Nb4, Al8Co30Cr18Fe9Ni31Nb2Ti2 and Al8Co30Cr18Fe9Ni31Ti4 high entropy alloys (HEAs) were investigated using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), hardness and tensile testing. TEM and XRD analyses revealed the formation of γ''-Ni3Nb/γ (FCC), double FCC and γ'-Ni3Al/γ (FCC) structure for as-cast Al8Co30Cr18Fe9Ni31Nb4, Al8Co30Cr18Fe9Ni31Nb2Ti2 and Al8Co30Cr18Fe9Ni31Ti4 HEAs, respectively. The hardness and yield strength values were found to increase with the addition of Nb while the ductility of alloys increased with the increase in Ti concentration, significantly. The as-cast Al8Co30Cr18Fe9Ni31Ti4 alloy exhibited an excellent combination of ultimate tensile strength of 844 MPa and an elongation of 29.8% due to the coherent phase relation between γ' precipitates and γ matrix. The fractured surfaces of as-cast Al8Co30Cr18Fe9Ni31Nb4, Al8Co30Cr18Fe9Ni31Nb2Ti2 and Al8Co30Cr18Fe9Ni31Ti4 HEAs showed typical dimple type ductile fracture under tension test. [ABSTRACT FROM AUTHOR]

The aim of this study is to produce multifunctional cotton fabric with improved mechanical performance by utilizing the potentiality of ZnO nanoparticles. Synthesized ZnO nanoparticles are immobilized on the cotton fabric with the following recipes: (i) only ZnO nanoparticles, (ii) ZnO nanoparticles with an acrylic binder, and (iii) ZnO nanoparticles with polyethylene wax emulsion and binder. SEM (Scanning Electron Microscope) and EDS (Dispersive Energy Spectroscopy) are used to investigate the surface morphology. For analysis of functional properties antimicrobial activity, ultraviolet (UV) protection ability, and crease resistance are measured. Several mechanical properties are also investigated. The results show that the treatment with the first and second recipes improves the functional properties but degrades the mechanical properties. In contrast, nano ZnO treatment with the third recipe improves mechanical as well as functional properties. Specifically, the nano deposition by this recipe increases the tensile strength, tearing strength, elongation, abrasion, and pilling resistance. Therefore, the findings in this research will boost up the confidence of textile researchers and manufacturers for the use of nano ZnO and understanding its characteristics in the production of valuable functional textiles. [ABSTRACT FROM AUTHOR]

The present work aims to investigate the effect of nanofiller, lead oxide on the mechanical, thermal, and water intake behavior of luffa fiber-reinforced epoxy polymer matrix composites. Filler material PbO of 20 nm was added in different weight proportions along with luffa fiber to the matrix and the compression molding technique was used for the fabrication of the composite laminates. Tensile, flexural, and impact properties were studied on the prepared samples. The influence of lead oxide on glass transient temperature (Tg) and the curing of epoxy were also studied using the Differential scanning calorimeter. The optimum mechanical and thermal properties were observed on the addition of 1.25 wt. % of nanofiller. The morphological images show various defects like interfacial behavior, fiber pulls outs, voids, and internal cracks, and these were examined using a scanning electron microscope. Hence the present investigation showed that the addition of nanofiller could enhance the mechanical strength of the natural fiber composite. Further, it enhanced the moisture resistance and thus could find potential structural and packaging applications. [ABSTRACT FROM AUTHOR]

Hybrid composite refers to as an attractive structural material due to its ability to provide a better combination of properties with respect to single-particle-containing composite. Composites were prepared by using customised extruder machine at five levels (10, 20, 30, 40 and 50 wt%) of aluminium powder and silicon carbide loading. Microstructural analysis utilising scanning electron microscope and optical microscope was performed to observe the cohesiveness and distributions of matrix and reinforcement in the composites. Tensile, flexural, impact and hardness tests were conducted for the purpose of mechanical characterisation. Tensile strength increased up to 40 wt% particles loading and then decreased in 50 wt% particles loaded composite. Young's modulus, flexural strength, flexural modulus, and hardness increased with the increase of aluminium powder and silicon carbide reinforcement loading. On the other hand, impact strength showed an opposite trend. Based on the particle loading and uniformity, 40 wt% aluminium powder and silicon carbide reinforced composite revealed the best set of mechanical properties. [ABSTRACT FROM AUTHOR]

Hybrid laminates made using natural fibers have been finding applications in diverse fields such as automotive parts, building structures and sports goods. These laminates incorporate the benefits of the reinforcements used in constructions. The present work deals with the fabrication of hybrid laminate comprising of the natural fibers areca and kenaf in varying stacking sequences through the hand layup method. Epoxy resin (LY556) and hardener (HY951) are mixed in the ratio of 10:1 to prepare the matrix material. Six different hybrid laminates having five layers of areca and kenaf in different stacking sequences are produced. Two more laminates having either kenaf or areca in all the five layers and are produced to act as reference laminate. The prepared laminates are cut as per ASTM standards and subjected to tensile, compressive, flexural, impact and hardness tests in order to identify the properties of the fabricated laminates. The result shows that composite made with kenaf fiber as skin material and areca as core materials exhibit better tensile, flexural and hardness properties. Likewise, composites with outer layers of areca and core layers of kenaf fibers have high compressive and impact strength. The fractured surfaces after the mechanical tests are investigated through the Scanning Electron Microscope (SEM). [ABSTRACT FROM AUTHOR]

Liquid metallurgy method based aluminum matrix composites (AMCs) are extensively utilized in diverse engineering applications including shipbuilding, structural, nonstructural, automotive, and aerospace owing to their superior strength, weightless, low density, excellent corrosion, and wear resistance. In the present investigation, liquid state technique was employed to prepare the LM4/aluminum nitride (AlN) composites containing four different mass proportion of AlN filler particles content. The weight proportion of filler particles from 0 to 12 wt% at 4 wt% intervals. Scanning electron microscope (SEM) images demonstrated a even dispersal of filler particles in the matrix. The test outcomes discovered that the LM4/12 wt% AlN AMCs had revealed extreme hardness, tensile, compression strength than the nonreinforced base matrix alloy. A considerable enrichment in the tensile strength is associated with the incorporation of AlN particles into LM4 matrix. The manufactured composites reveal high mechanical properties when compared with the alloy without reinforcement. The improvement of those lightweight AMCs with superior mechanical characteristics has a extreme potential to be employed for aircraft, structural and automobile applications. [ABSTRACT FROM AUTHOR]

Bacterial cellulose is one of the widely discussed biomaterials due to its unique physical, mechanical and chemical characteristics. In this research, bacterial cellulosic film (BCF) was developed using Acetobacter xylinum strain in green tea as a source of carbon under static culture conditions. The developed BCF was evaluated for their morphological properties using a scanning electron microscope and the approximate fiber diameter noted as 38–40 nm. The purity of the cellulose evaluated through an X-ray diffraction method identified that the developed cellulose is Iα rich – triclinic type with 89.61% of crystallinity. The thermal behavior of the BCF was evaluated using TGA and DSC. The results indicated that the major weight loss occurred from 250 to 500°C. The glass transition temperature (Tg) of the developed BCF was very high and it was 165°C. Concerning the mechanical properties, the BCF had lower tensile strength (13.82 Kgf/Cm2), Elongation (10.13 mm) and air (19.72 cm3/cm2/sec) and water vapor permeability value (151 g/m2/day) than the woven cotton fabric. However, the water absorbency (0.7 s) and water holding capacity (320%) are superior to the cotton fabric. The contact angle of the BCF was noted around 28.53°, which is an indication of the higher hydrophilic nature of the BCF. These results provide an insight into the potential applications of bacterial cellulosic material in the apparel and textile sector. [ABSTRACT FROM AUTHOR]

The presence of a secondary phase between the fibres and the matrix has proved to be a good approach for interphase tailoring for enhanced load transfer. In this regard, an optimization of the low-temperature hydrothermal growth process of ZnO-nanorods on different basalt substrates as a function of different growth times was performed. Scanning electron microscope and X-ray diffraction analysis revealed the best results in terms of homogeneity and uniformity of the ZnO nanostructures for the longest growth time, i.e., 5 h for basalt fabrics and 120 minutes for single basalt fibres. The presence of ZnO nanostructures induced a hydrophobic behaviour with contact angles up to 116° for 4- and 5-h growth processes. Fibre/matrix adhesion was characterized by single fibre pull-out tests, showing a 16% increase in interfacial strength. ZnOs added also photocatalytic properties to basalt fibres, enabling a selective removal of organic pollutant equal to 37%. [ABSTRACT FROM AUTHOR]

The aim of the present study is to use microwave sintering technique to fabricate Al-Graphene oxide (Al-GO) composites with different concentration of GO (i.e. 0.5 wt %, 1 wt%, and 2 wt%) at 600°C for 15 min. X-ray diffraction (XRD) and scanning electron microscope (SEM) were utilized to investigate the microstructural development. Uniform dispersion of GO was obtained in Al-0.5GO composite whereas other concentration of Al-GO composites suffered from agglomeration of GO particles. In addition to microstructure, the hardness, compressive strength, and corrosion resistance of the Al-GO composites were also examined. A remarkable improvement in compressive strength (up to 200%) was attained in Al-0.5GO composite while further addition of GO deteriorated the mechanical strength and hardness due to agglomeration and increase of the microporosities. In spite of significant enhancement in compressive strength with optimum amount of GO nanoplatelets (i.e. 0.5%), the corrosion resistance of the Al-GO composites was degraded by the addition of GO nanoplatelets mainly due to the increased amount of microporosities and surface roughness originating from agglomeration of GO nanoplatelets. [ABSTRACT FROM AUTHOR]

In the present experimental investigation, titanium carbide (TiC) and red mud are reinforced with aluminium 7075 (Al7075) at 3, 6, 9 and 12 percentages by weight of matrix to produce a flat casting with the help of stir casting process. The mechanical properties such as yield strength, ultimate tensile strength, microhardness, and % elongation are tested and compared. The distribution pattern of the reinforced particles of the samples is studied through a Scanning Electron Microscope (SEM) and X-ray diffraction (XRD) technique. Finally, the micrographs of the fractured surface reveal the features, namely dimples, cracks, voids, ridges and particle fracture that characterise the features of the fractured composite. The ultimate tensile strength of Al/TiC metal matrix composite (MMC) is increased by 48%, whereas a 71% decrease was observed with the addition of red mud. Further, the hardness is increased by 6%, and 62% with TiC and Red mud reinforced AMMCs. [ABSTRACT FROM AUTHOR]

This work aims to evaluate the effect of post-heat treatment and quenching on the hardness, coating thickness, morphology, wear, and microstructure of the coatings made on steel travelers. The test result shows that all the quenched samples have similar hardness. Wear tests of the specimens show that Type-I oil quenched specimens have better wear resistance compared to other specimens. Atomic force microscope results reveal that Type-I oil-quenched travelers have a smoother surface than water and air-cooled travelers. Scanning electron microscope images show that the distribution of plating on the substrate is not uniform. After baking, the coating becomes uniform. However, some small voids are present in the coating due to improper surface activation before the plating process. [ABSTRACT FROM AUTHOR]

Applicability of natural fiber-reinforced composites in automobile, aerospace like sectors has been increasing as more number of research works is concentrating on natural fibers owing to their eco-friendly nature. Biodegradability of natural fibers is main advantage of them over artificial fibers. Natural fiber-reinforced composite possesses good thermal and mechanical properties besides other requirements. For this reason, investigation of one such natural fiber-reinforced composites has been the focus of the present study. In the present work, composites made up of abutilon indicum fiber reinforced with epoxy have been prepared. Mechanical, morphological, thermal, and spectroscopic studies on the test specimens prepared using the above composites were carried out to evaluate their respective strengths. Also, the effect of alkali treatment (NaOH) for the fibers was studied and evaluated. Scanning electron microscope results indicated that the composite made up of alkali-treated fibers possessed better mechanical properties. Using differential thermal analysis–thermogravimetric analysis apparatus thermal behavior of the composites and using Fourier transform infrared spectroscopic studies, the presence of function groups like C–O, C–H was determined. Thus, characterization of abutilon indicum fiber-reinforced epoxy composites has been carried and properties are evaluated for their applicability to automotive, aerospace similar industries. [ABSTRACT FROM AUTHOR]

Usage of composites with natural fiber reinforcement is drastically increasing in recent times because of their low density, biodegradable nature, and low cost. However, natural fibers have certain core problems such as poor adhesion between the fiber and matrix and a relatively high degree of moisture absorption. Alkaline treatment of natural fibers is aimed at improving the adhesive strength so that effective stress transferability takes place in the composite. In the present work, Cordia-Dichotoma fibers were treated with sodium hydroxide (NaOH) and composites were prepared with different weight ratios of these fibers reinforced with epoxy. The prepared composites were tested for their tensile and flexural strengths (mechanical properties). Besides, for a comprehensive material characterization, IR spectroscopy (FT-IR), scanning electron microscope, and thermogravimetric analysis were carried out. This work investigates the influence of aforementioned NaOH treatment on thermal, mechanical, and morphological properties of the composite material. [ABSTRACT FROM AUTHOR]

Safer environmental requirements have resulted in significant interest in natural polymer-based materials to increase sustainability. In this perspective, wood polymer nanocomposites are of particular interest. Wood polymer nanocomposites were prepared from modified soybean oil, wood flour and cetyl trimethylammonium bromide modified bentonite using the compression-molding technique. Fourier transform infrared spectroscopy and X-ray diffractometric studies were used to confirm the successful modification of bentonite. Incorporation of 3 wt% of bentonite in the composites produced significant improvement in properties compared to those of 1 and 5 wt%. Furthermore, in comparison to the unfilled nanocomposites, nanoclay-filled ones showed an enhanced UV resistance property as judged by lower weight loss and carbonyl index. The decrease in mechanical properties of UV-exposed unfilled composites was more significant compared to those of nanoclay-filled composites. Scanning electron microscope and transmission electron microscope were used to study the surface morphology and distribution of the bentonite into the composites. In addition, with the incorporation of bentonite, significant increase in thermal, mechanical and flame-retarding properties was observed. [ABSTRACT FROM AUTHOR]

In modern age, prosperous business, industrial, social, and leisure activities improve and ensure the quality of lives considerably, but are inevitably accompanied with insecurity and dangers that lurk anywhere anytime. People are concerned about safety and have increasing demands on self-protection in terms of working/living environment, accidents, and raising crime rates. The increasing demands of protective textiles cause the mass production of high performance fabrics, leaving considerable amount of high performance selvages. In this study, three kinds of high performance recycled selvages, including Nomex, Kevlar, and PET selvages, are used to make high-performance hybrid composites. The recycled selvages are smashed into staple fibers using a nonwoven manufacturing process. Each recycled staple fibers are individually combined with low-melting-point polyester (LPET) fibers at ratios of 9:1, 7:3, and 5:5, and processed with thermal compression. The LPET fibers contribute to the hybrid composites with thermal bonding points, which decrease the voids between fibers, limit the fiber slide, and enhance the friction force between fibers. The shearing, expelling, and friction functionalities of LPET fibers are expected have a positive influence on the mechanical properties of the high-performance hybrid composites. The morphology of hybrid composites is observed using a scanning electron microscope, and the air permeability, tensile strength, tearing strength, and bursting strength of hybrid composites are evaluated, examining the optimal parameters. [ABSTRACT FROM AUTHOR]

Effect of heat treatment on the recovery of microstructure and mechanical properties of a service-exposed IN939 superalloy was studied. Four-stage heat treatment was performed on the service-exposed alloy. The microstructures of the service-exposed and rejuvenated alloys were examined by optical and scanning electron microscopes. The hardness, tension, and stress-rupture tests were carried out to characterise the mechanical properties. The results showed that the heat treatment could rejuvenate the microstructure of the alloy that was deteriorated during the service at high temperatures. Decomposed MC carbides were transformed to new fine carbides, continuous M23C6 carbides were dissolved and new discontinuous carbides along the grain boundaries were regenerated and, finally, the fine γ׳ particles were reformed. The microstructural recovery resulted in an increase in the hardness and ultimate tensile strength of the alloy. The results also showed that the creep behavior of the alloy at a testing temperature of 850°C could be improved by the heat treatment. [ABSTRACT FROM AUTHOR]

The aim of this paper is to present research findings on the measurements of mechanical, morphological, and thermal properties of Roselle fiber-reinforced thermoplastic polyurethane composites. The Roselle fiber/thermoplastic polyurethane composites were prepared with fibers of different sizes such as 125 µm and lower, 125–300 and 300–425 µm by internal mixer and hot press at 170°C. The results show that mechanical properties (tensile, flexural, and impact properties) of the composites were improved with the increase in fiber sizes. The highest tensile (10.45 MPa), flexural strength (6.93 MPa), and impact strength (20.22 kJ/m2) was obtained from composites with 300–425 µm fiber size of Roselle fiber/thermoplastic polyurethane composites. Morphological properties of dispersion fiber and tensile fracture surfaces were studied using scanning electron microscope. Thermal properties of the composites were studied using thermogravimetric analyses and results showed that the thermal decomposition effect was almost similar for all compositions. [ABSTRACT FROM PUBLISHER]

The influence of reinforcement particle size variation plays a major role on the properties of Al–SiCpcomposite. Therefore, this study aim to investigate the mechanical and wear performance of single particle size (SPS) and multiple particle size (MPS) Al–SiCpcomposite prepared by stir casting process. The SPS comprises three categories; fine (15 ?m), intermediate (40 ?m) and coarse (80 ?m) particle sizes and combination of the three sizes accounts for the MPS in the ratio 1:1:2, respectively. Oxidation of the SiCpand addition of 1 wt% Mg during composite processing resulted to interface reaction products such as MgO (magnesium oxide) and MgAl2O4(magnesium aluminate) which suppresses the potential formation of undesired Al3C4(aluminium carbide). The study reveals that MPS composite improved the hardness and impact properties with enhanced wear performance compared to SPS composite. Characterization of the composite morphology and phases was performed using scanning electron microscope and X-ray diffraction analysis. This study provides an effective method of optimizing the properties of Al–SiCpcomposite by integrating MPS with low volume fraction of reinforcement phase. [ABSTRACT FROM AUTHOR]

It is important to optimize the properties of a material for a particular application, hence, to find the suitable material for tribological applications, the wear and friction behaviour of AA5052in situcomposites with different kind of reinforcements have been investigated. For present study, threein situformed composites have been produced with different reinforcements namely Al3Zr, ZrB2and combination of both (Al3Zr + ZrB2) by direct melt reaction (DMR) technique. The as-cast composites and base alloy have been characterized by X-ray diffraction (XRD), optical microscopy, electron microscopy, tensile testing, hardness and dry sliding wear and friction tests. XRD results indicate the successful formation of second phase reinforcement particles in all composites. Wear test results indicate that the cumulative volume loss increases with an increase in sliding distance while coefficient of friction shows a fluctuating tendency, whereas with increasing applied load, wear rate shows an increasing trend while coefficient of friction shows decreasing trend. The variation of wear rate with composites indicates that the composite with multiple reinforcement (Al3Zr + ZrB2) has lowest wear rate among all as-cast composites and base alloy, while coefficient of friction is higher. The responsible mechanisms concerned with wear and friction results have been discussed in detail with the help of the observation on worn surface analysis by scanning electron microscope (SEM) and 3D-profilometer. All tribological results have been correlated with the microstructural properties, strength parameters and bulk hardness of the composites. [ABSTRACT FROM AUTHOR]

Green/bio-based composites of poly(lactic acid) and lignin were prepared by melt blending in a twin-screw extruder. Thermal and mechanical properties, phase interaction, and morphology of the composites have been investigated. Fourier transform infrared studies elucidated the existence of intermolecular hydrogen bonding between poly(lactic acid) and lignin. Scanning electron microscopy studies revealed an extent of diffused phase boundaries between poly(lactic acid) and lignin which also indicated significant interaction between them. Tensile properties showed significant increase over neat poly(lactic acid) with lignin loading (0–0.28 volume fraction) which further justified using theoretical models. Izod impact strength decreased with lignin content. [ABSTRACT FROM PUBLISHER]

Within the scope of experiments, the effect of stitch yarn type (aramid, glass and nylon), and biaxial, warp and weft, and yarn type (aramid and glass) was investigated in the biaxial weft-knitted (BWK) composites. Five different types of composite panel, which include fiber contents, such as glass-glass-glass, glass-glass nylon, glass glass aramid, aramid glass aramid and aramid aramid aramid were fabricated by hand lay-up method. After production of composite panels, tensile, three-point bending and three-point, bending impact tests were conducted on specimens. Microstructural characterization of tested materials was performed using a scanning electron microscope. This study showed that composites with BWK preforms consisting of fiber combinations, such as aramid-aramid-aramid, had higher tensile strength (in course direction), of aramid-glass-aramid had higher bending strength (in course direction), and of glass glass aramid had higher three-point bending impact properties (in course and wale directions) than other types of tested composite structures. [ABSTRACT FROM AUTHOR]

In this article, the mechanical and dry sliding wear characteristics of synthesized m-cresol novalac epoxy composites filled with silicon carbide (SiC), aluminum oxide (Al2O3), and zinc oxide (ZnO) have been studied using a pin-on-disc apparatus. The influence of wear parameters such as applied normal load (20–40 N), sliding velocity (1.8–3.6 m/s), filler content (5–15 wt%), and sliding distance (1,000–3,000 m) on the coefficient of friction and specific wear rate of these composites have been investigated under dry sliding conditions. A design of experiment technique, response surface methodology, has been used to model the friction and wear behavior of these composites. The experimental plan for four factors at three levels using face-centered central composite design has been employed. The results showed that the hardness, tensile strength, and flexural strength of these composites increased with 5 to 10 wt% filler contents and decreased for 15 wt% filler content. The compression strength of these m-cresol novalac epoxy composites increases with an increase in the filler content from 5 to 15 wt%. The worn surfaces of these composite specimens were examined using a scanning electron microscope (SEM) to explore the wear mechanisms. [ABSTRACT FROM AUTHOR]

Laser irradiation effects on surface, structural and mechanical properties of Al–Cu–Mg alloy (Al–Cu alloy 2024) have been investigated. The specimens were irradiated for various fluences ranging from 3.8 to 5.5 J/cm2using an Excimer (KrF) laser (248 nm, 18 ns, 30 Hz) under vacuum environment. The surface and structural modifications of the irradiated targets have been investigated by scanning electron microscope (SEM) and X-ray diffractometer (XRD), respectively. SEM analysis reveals the formation of micro-sized craters along the growth of periodic surface structures (ripples) at their peripheries. The size of the craters initially increases and then decreases by increasing the laser fluence. XRD analysis shows an anomalous trend in the peak intensity and crystallite size of the specimen irradiated for various fluences. A universal tensile testing machine and Vickers microhardness tester were employed in order to investigate the mechanical properties of the irradiated targets. The changes in yield strength, ultimate tensile strength and microhardness were found to be anomalous with increasing laser fluences. The changes in the surface and structural properties of Al–Cu alloy 2024 after laser irradiation have been associated with the changes in mechanical properties. [ABSTRACT FROM AUTHOR]

The influence of heating mode on microstructure and mechanical properties of TiB2–based ceramic tool materials were studied. The chemical composition was detected by X-ray diffraction (XRD) and energy dispersive spectrometry (EDS), and the microstructure of the samples was observed using a scanning electron microscope (SEM). The brittle phases of Ni4B3and W2B were found in composite materials, which were harmful to the improvement of the mechanical properties of the composite. The results showed that the mode of direct heating-up not only can refine grains, but can also make the microstructure uniform, thereby improving the mechanical properties of materials. [ABSTRACT FROM AUTHOR]

A series of plastic materials for an organs injury stress assessment model use were prepared using a blend of potassium stearate (PS), sodium stearate (SS), polyvinyl alcohol (PVA) and paraffin liquid (PL) at various weight ratios. The mechanical properties of the materials were investigated via a compression test using Instron, and the results indicated that the PS/SS/PVA/PL blend with a weight ratio of 0·35∶0·35∶0·02∶0·28 had superior plastic deformation properties. The PS/SS/PVA/PL blend's weight ratio of 0·35∶0·35∶0·02∶0·28 was characterised by using Fourier transform infrared spectroscopy, a scanning electron microscope and differential scanning calorimetry. For a comparison, blend samples of PS/SS/PVA/PL with weight ratios of 0·68∶0∶0·2∶0·30 and 0∶0·68∶0·2∶0·30 were measured using the same methods. The results show that the plastic deformation mechanism is due to the optimal combination of weight ratio of the PS and the SS, and that the carbon chain in the PVA is a backbone of the slip function. [ABSTRACT FROM AUTHOR]

Carbon nanotube/polysulfonamide (CNT/PSA) composite spinning solutions with different CNTs contents were prepared using the physical blending method. The corresponding composite fibers were extruded through a set of wet spinning unit and the composite membranes were prepared using a digital spin-coating technique. The distribution of CNTs in PSA matrix and the crystalline structure of composite fibers were investigated by scanning electron microscope (SEM) and X-ray diffraction, respectively. The influences of CNTs on mechanical properties as well as electrical conductivity of PSA composites were also analyzed. In addition, the general effective media equation was chosen to explain the electrical conductivity behavior of the CNT/PSA composites. The experimental results showed that CNTs with low contents can be distributed evenly in PSA; the crystallization in PSA was promoted at low CNTs contents; the mechanical properties of composites can be improved significantly; and the electrical conductivity of composites increased obviously and the percolation threshold of the blending system was at about 3 wt%. [ABSTRACT FROM AUTHOR]

Polysulfonamide/nano titanium dioxide (PSA/nano-TiO2) composite spinning solutions with various nano-TiO2 mass fractions were prepared using the solution blending method. The corresponding composite fibers were developed by wet-spinning technology and the composite membranes were prepared using the digital spin-coating technique. The properties of PSA/nano-TiO2 composite fibers and membranes were investigated by scanning electron microscope, Fourier transform infrared spectroscopy and X-ray diffraction, etc. The effects of nano-TiO2 and its mass fractions on the mechanical properties, thermal stability and ultraviolet resistance of PSA composites were also analyzed. The experimental results showed that nano-TiO2 with low mass fractions can be dispersed evenly in the PSA matrix; the blending of nano-TiO2 had no obvious influence on the molecular structure and the chemical composition of PSA fiber; the crystallization in PSA fiber was promoted at low nanoparticles mass fractions because it can act as a nucleation agent; the mechanical properties and the thermal stability of PSA/nano-TiO2 composites can be enhanced obviously by blending nano-TiO2 into PSA matrix. The ultraviolet resistance of PSA composites can be improved significantly with the increasing nano-TiO2 mass fractions and the 7 wt.% specimen showed the lowest UV transmittance. [ABSTRACT FROM AUTHOR]

Carbon fiber (CF) / poly (ethylene terephthalate) (PET) composites were prepared with various contents (2–15wt%) of short carbon fibers. To investigate the effect of surface treatment of the CF on the mechanical properties of the composites, three specimens were prepared; those with short carbon fibers (called SCF), short carbon fibers oxidized with nitric acid (called NASCF) and the fibers oxidized with nitric acid and treated with silane coupling agent (called SCSCF). Flexural, tensile and impact tests were performed to observe mechanical behavior of the specimens. The morphology of the specimens was also studied with a scanning electron microscope (SEM). SCSCF composite had better mechanical properties than the other composites with the same content of carbon fibers since the coupling agent resulted in better interfacial adhesion between the fiber and the matrix. [ABSTRACT FROM AUTHOR]

This experimental study was conducted to investigate the effect of melt cleanliness with respect to the presence of inclusions on the mechanical properties of AZ31 alloy. The type, morphology and size distribution of inclusions in the alloy were analysed. The tensile properties of the AZ31 alloy with and without melt purification were tested at room temperature. The fracture surface of the AZ31 alloy was observed by SEM to reveal the mechanism of fracture nucleation. By melt purification treatment, most of the inclusions are removed from the AZ31 alloy, and the average size of inclusions in the alloy is decreased from 16·5 to 2·0 μm. In addition, the tensile strength and especially the elongation of the alloy are increased. Tensile fracture analysis showed that the inclusions act as crack initiation sites during fracture. The MgO film, which is the main inclusion in the alloy, contributed to poorer mechanical properties. [ABSTRACT FROM AUTHOR]

The inter-cross-linked networks of unsaturated polyester (UP) toughened epoxy blends were developed. Montmorillonite (MMT) clay was dispersed into the same system to prepare blended epoxy/UP/clay nanocomposites in different weight ratios viz. 0%, 1%, 2%, 3% and 5%. Mechanical properties like tensile strength (TS), impact strength (IS) and interlaminar shear strength (ILSS) were characterized for the above nanocomposites. Blended nanocomposites were fabricated by high shear mechanical mixing followed by ultra-sonication process to get homogeneous mixing under the aid of in situ polymerization. Mechanical properties were studied as per ASTM standards. Data obtained from mechanical property studies indicated that the introduction of UP into epoxy resin improved the impact strength to an appreciable extent. Impact strength (IS) and tensile strength (TS) were significantly improved and optimized at 3 wt. % clay content when compared with neat blend (0 wt. % clay) composites. The homogeneous morphologies of the UP toughened epoxy and epoxy/UP/clay nanocomposite systems were ascertained using scanning electron microscope (SEM) studies. [ABSTRACT FROM PUBLISHER]

In this investigation, naturally woven coconut sheath, a new type of reinforcement was used. The composite was fabricated using compression molding machine. The mechanical properties like tensile, flexural and impact strengths were studied according to the ASTM standards. For comparison, conventionally used glass fiber-reinforced composites were also fabricated and tested. In all the testing, the coconut sheath-reinforced polyester composite showed enhanced results. For further improvement in the properties, chemical modification such as silane treatment was given to the fibers. As expected, the mechanical properties of coconut sheath-reinforced composites were improved. [ABSTRACT FROM AUTHOR]

Polypropylene (PP) sheets obtained through a two-step process (masterbatch method) were crosslinked by electron beam irradiation. The crosslinked PP sheets were foamed in an oven under different processing conditions. The effects of foaming temperature and time on the mechanical properties and cell structure of PP foams were studied. With the foaming temperature increasing and foaming time lengthening, both the compression modulus and compression strength dropped. Scanning electron microscope (SEM) was employed to study the morphology and cell structure of different samples and the related morphology parameters were acquired. The results showed there was an optimum temperature and time that produced the maximum expansion ratio or the minimum foam density. As foaming temperature or time increased, the cell size increased and the cell density decreased regularly. Excessively high foaming temperature and overly long foaming time caused the coalescence and even the collapse of the cells. [ABSTRACT FROM AUTHOR]

Polyamide-CaCO3 nanocomposites were prepared by melt intercalation on twin-screw extruder. Various particle sizes (23, 17 and 11 nm) of CaCO3 were synthesized by in-situ deposition technique. The shape and sizes of nano-CaCO3 particles were confirmed by transmission electron microscopy (TEM). Nano-CaCO3 was added from 1 to 4 wt% in the polyamide. Properties such as Tensile strength, Elongation at break, Hardness, and Flame retardency were studied. These results were compared with commercial CaCO3 filled composites. Nano-CaCO3 filled in polyamide shows, 3 fold improvement in Young's modulus in comparison to commercial CaCO3 and 4-7 folds to virgin polyamide. Besides that, a polyamide nanocomposite shows 2 times improvements in flame retarding and vicat softening properties compared to commercial CaCO3. Moreover, thermal degradation was studied on TGA and found to be improved compared to commercial CaCO3. This was due to uniform dispersion of nano-CaCO3 with greater surface area in comparison to commercial CaCO3 in the polyamide matrix. Extent of dispersion of nano-CaCO3 was studied along with microcracks generated during tensile testing using scanning electron microscope (SEM). [ABSTRACT FROM AUTHOR]

In this article, the effect of aging time in Al-Li-Hf alloy was studied. The samples were homogenized at 600°C and aged from 0.166 to 100 h at 190°C in thermal oil. According to scanning electron microscope (SEM) images, the effect of aging in the intermetalic precipitates changes its morphology as well as composition. For as cast alloys small Hf-Li precipitates with high Hf content exist. When considering aging samples the size precipitates increases, as does Hf content, from 30.74% for 1 h to 59.85% for 100 h. For an aging time of 100 h, the microhardness Vickers show better values which can be attributed to the Hf-Li solubility into the Al matrix to the point where their precipitation of intermetalic precipites and further cause changes in the dendritic arm spacing. [ABSTRACT FROM AUTHOR]