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Reactive polyimide (PI) containing phenolic hydroxyl groups was prepared by the polymerization of 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane and mixed thiodiphthalic anhydride. A series of epoxy resin composites were obtained by adding reactive PI to N,N,N′,N′ -tetraglycidyl-4,4′-diamino-diphenylmethane (TGDDM) epoxy resin in different proportions. The effect of PI content on curing behavior, thermal properties, and mechanical properties was carefully investigated. Even a small amount of PI addition improved the mechanical properties and heat resistance of the epoxy resin, particularly the fracture toughness. Among them, epoxy resin composites EP-PI-1.5 with the addition of 1.5 wt% PI showed the best mechanical properties, whose impact strength, fracture toughness, and tensile strength were increased by 114%, 59%, and 34%, respectively. The phase morphology was also investigated to illustrate the fracture mechanism by scanning electron microscope (SEM) characterization. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) impart great multi-functionality when reinforced with a polymer matrix. This paper shows the qualitative and quantitative improvements of the mechanical, electrical, and electromagnetic interference shielding effectiveness properties with the additions of the multiwalled carbon nanotubes (MWCNTs) and functionalized MWCNTs (FMWCNTs) in ethylene methyl acrylate (EMA) polymer. Mechanical characterization is performed through tensile testing, and electromagnetic interference shielding effectiveness (EMI SE) is calculated from the scattering parameters obtained from the vector network analyzer. Both properties improve compared to neat polymer with the reinforcement loadings up to a critical value, from where the properties start to degrade due to the agglomeration of the CNTs. FMWCNTs provide better performance in terms of properties over the MWCNT reinforced nanocomposites. Morphological characterization using a scanning electron microscope justifies a lower percolation threshold of FMWCNT/EMA composite by better electrical conductive network formation. At 10 wt% of FMWCNT loading, the FMWCNT/EMA composite shows 25.1 dB of EMI shielding efficiency combined with excellent mechanical and electrical properties extending its potential use in both industry and academia as an excellent flexible EMI shielding material. [ABSTRACT FROM AUTHOR]

Polymer composite materials were prepared using kaolinite nanoclay as reinforcement in different weight fractions (3, 5 and 7) %, and blends of epoxy and polymethyl methacrylate (PMMA) as matrices. The current work aims to prepare a composite material with good thermal and acoustic insulation, besides improved mechanical properties, and the investigation of the effect of this nano additive on the compatibility between the two constituents of the blend, and how this compatibility might be beneficial to the performance of the prepared composite. The blend with an optimum mixing ratio (OMR) was chosen via impact test results; thus, the (80:20) percentage of epoxy and PMMA was chosen. The reinforced specimens showed an improvement in mechanical (impact and flexural) properties besides sound insulation and thermal conductivity, with the specimen reinforced with 7% nanoclay having the highest impact strength (97*10−3) KJ/m2 and the highest thermal conductivity value of (0.34) W/m.°C, with a sound intensity value 95.6 decibels at frequency 10,000 Hz. The scanning electron microscope images showed two separate phases in the unreinforced blend. In comparison, the 7% reinforced specimen showed a rough interface between the two polymer phases, suggesting a positive effect of nanoclay addition on compatibility. The differential scanning calorimeter showed two distinct glass transition temperatures for both reinforced and neat specimens, which belong to the glass transitions of both constituents (epoxy and PMMA). The main difference is the lower temperature gradient accompanied with the (nanoclay/blend) composite than the neat one. Although the blend remained immiscible, nanoclay had contributed to the compatibility and improved mechanical properties. [ABSTRACT FROM AUTHOR]

This article addresses the effect of nanocrystalline cellulose (NCC) on the mechanical and thermal properties of polypropylene (PP). A new approach was adopted to produce mechanically improved and thermally stable PP-NCC nanocomposite. This approach involved producing optimized PP-NCC nanocomposite by adding NCC nanoparticles to PP matrix at different concentrations by means of injection molding process. The aim of this work was to find the optimum NCC concentration to enhance the mechanical and thermal properties of the PP matrix. The mechanical and thermal behavior of PP-NCC nanocomposite was studied by performing three-point bend, nanoindentation, differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and Fourier transform infrared (FTIR) spectroscopy tests. The results showed that the mechanical properties of strength, modulus, and hardness of the nanocomposites increased with the addition of NCC by 6.5%, 19%, and 150%, respectively. DSC results showed that the addition of NCC to PP does not affect the thermal stability (melting temperature). However, TGA showed that upon inclusion of NCC nanoparticles, the thermal stability of the samples improved compared to pure PP except for the 5% added NCC. This is attributed to the presence of NCC rod-like particles that dissipated heat by generating tortuous paths, as depicted in the SEM results and verified by FTIR results. [ABSTRACT FROM AUTHOR]

As a rapidly developing additive manufacturing technology, fused deposition modeling (FDM) has become widespread in many industry fields. It can fabricate complicated geometries using filament of thermoplastic materials such as PP, polylactic acid, acrylonitrile butadiene styrene, etc. However, poor mechanical properties of raw materials limit their application. Poly-ether-ether-ketone is a type of special engineering plastic with high performance, which could be further reinforced by adding carbon fibers (CFs). During FDM process, the mechanical properties of printed parts are largely subject to careful selection of process parameters. To improve the mechanical properties of PEEK and CF/PEEK 3D-printed parts, the effects of various process parameters including building orientation, raster angle, nozzle temperature, platform temperature, ambient temperature, printing speed, layer thickness, infill density, and number of printed parts on mechanical properties were investigated. The tensile fracture interfaces of printed parts were observed by scanning electron microscope (SEM) to explain the influence mechanism of process parameters. In the single factor experiments, flat and on-edge specimens show the best tensile and flexural strength, respectively; the specimens with raster angle ±45° and 0° show the best tensile and flexural strength, respectively. When the nozzle temperature at 500°C, platform temperature at 200°C, ambient temperature at 150°C, printing speed is 20 mm/s, layer thickness is 0.2 mm, and infill density is 100%, the printed parts exhibit the best mechanical properties. [ABSTRACT FROM AUTHOR]

In order to understand the evolution of the structure–property relationship between the crosslink density and mechanical properties of polyurethane-urea/sodium silicate (PU/SS) hybrid composites, a series of PU/SS composites with 2.5 wt% organofunctional silanes and pure PU/SS composites are investigated at different curing time. Mechanical properties, the fracture surface morphology, and thermo-mechanical properties of these PU/SS composites are characterized by electron omnipotence experiment machine, scanning electron microscope, and dynamic mechanical analysis (DMA), respectively. The mechanical test results show the strength and fracture toughness of the PU/SS composites first increase and then stabilize during cure, and the modification leads to PU/SS composites with significantly higher mechanical properties. Further, the morphology of fractured samples also reveals that the longer curing time and the modification of the PU/SS composites means a higher curing degree. Moreover, the increase in the crosslink density calculated from the DMA tests quantitatively confirmed the positive influence of the curing time and the modification in enhancing mechanical properties. In addition, it is also found that the mechanical properties of the PU/SS composites not only depend on the crosslink density but also on the well-dispersed hybrid PU/SS system. [ABSTRACT FROM AUTHOR]

In this work, a comparative assessment of the mechanical properties of chopped glass-carbon-aramid fiber reinforced polypropylene (PP) composites was carried out. Reinforcement and matrix materials were mixed with the extrusion method, and then composite materials were produced in the form of plates with the press molding technique. The composites' tensile, 3-point bending, and drop weight tests were carried out and the surface morphology of the fractured surfaces was examined by Scanning Electron Microscope (SEM). The tests' results indicate that the mechanical properties increase significantly in the presence of fiber. On the other hand, it is observed that the effect in percentage decreases as the fiber content increases. Moreover, It was observed that some of the fiber materials were pulled out from the matrix as a result of stress. ANOVA analysis using S/N values, and F-Test were performed to observe the effectiveness of each test factor (fiber type, and fiber additive content) on the test results. Finally, an optimization study was carried out to obtain the mathematical expression by fitting the experimental data. [ABSTRACT FROM AUTHOR]

The main objective of this research was to study the influence of an enzymatic treatment process of date palm fibers on their chemical and morphological properties as well as the physical and mechanical characteristics of composites filled with raw and treated fibers. To this end, three extraction approaches were considered (a combination of xylanase and pectinase enzymes, xylanase enzymes followed by a pectinase one and pectinase enzyme followed by xylanase). Chemical and morphological analyses were performed on raw and treated fibers. The tensile test of the manufactured composites was achieved, using extrusion and injection molding process. These composites were also subjected to water absorption tests. The results showed that non-cellulosic components decreased after enzymatic treatments while the cellulose content increased significantly. The scanning electron microscope morphological analyses showed that the extraction with the combination of these enzymes is very effective as a fibrillation phenomenon. Composites with high rigidity were observed in the case of enzymatically treated fibers. These composites reveal a better moisture resistance compared to the untreated fibers. Graphical Abstract [ABSTRACT FROM AUTHOR]

Thermal, electrical, as well as mechanical behavior of blends of polyamide 6/polystyrene (PA6/PS) (50/50 wt/wt%) loaded with different concentrations of lead dioxide (PbO2) were investigated for X-ray shielding. Thermal stability and hardness (shore D) of these composites are studied. Addition of PbO2 decreases the thermal stability of the prepared composites. Stability of thermal properties confirmed by determining the activation energy for the thermal decomposition of unfilled PA6/PS and filled composites according to the Horowitz and Metzger method. Dielectric properties of bulk PbO2 have been investigated as a function of frequency and temperature in the frequency range from 40 Hz to 5 × 106 Hz and in the temperature range from 293 K to 423 K. The characterization of the prepared composites is done using scanning electron microscope. With PbO2-loaded PA6/PS blends composites, the dielectric properties were significantly influenced by γ-irradiation effects that ε ′ and ε ″ values increase with radiation dose up to 100 kGy for samples loaded with PbO2. Linear attenuation coefficient μ and half-value layer (HVL) of all composites strongly depend on the concentration of the filler used and the applied voltage of X-ray machine. HVL of the obtained composites that loaded with 100 wt/wt% of PbO2 nearly 3 mm can be used as X-ray tube housing, equipment housings and castings, electronic devices protection, and so on. [ABSTRACT FROM AUTHOR]

This study investigated the effect of carbon black (CB) filler loading on mechanical and rheological properties of natural rubber (NR)/styrene-butadiene rubber (SBR)/nitrile butadiene rubber (NBR) ternary rubber nanocomposites. The nanocomposites were prepared using a melt mixing method. Four different samples with different filler loadings namely S2 (15 phr), S3 (30 phr), S4 (45 phr), and S5 (60 phr) were prepared in this work. The mechanical properties of these samples were investigated such as tensile strength, stress at 100, 200, and 300% elongations, elongation at break %, tear strength, compression set, compression stress, and crosslink density. Results indicate that minimum torque, maximum torque, tensile strength, stress at 100, 200, and 300% elongations, elongation at break %, tear strength, compression set, compression stress, and crosslink density were increased while the scorch time, cure time, cure rate index, elongation at break %, swelling coefficient, and filler–rubber interaction decrease with increasing CB loading. The higher value of tensile strength for these samples was S4 (loading with 45-phr CB). Therefore, had higher stiffness compared to the other content ratio. Additionally, S4 showed 233.58% increment in tensile strength. These results showed that the optimum filler loading can increase the compatibility between CB and NR/SBR/NBR. These results were confirmed by scanning electron microscope micrography. [ABSTRACT FROM AUTHOR]

In recent times, polymer composites have played an epochal role in transforming material science. Some of their properties such as toughness, strength, flexibility and rigidity have helped them supplant conventional materials such as iron, steel, and aluminium on several occasions. Apart from this, they are light in weight and more cost-efficient, which make them a viable alternative. They have found their application in several fields such as automobile industry, aerospace industry, construction and pipeline industry. Owing to its excellent impact strength, tensile and hardness, natural fibres serve as an excellent replacement. Natural fibres are an environmental friendly, biodegradable and are readily available. The present investigation uses a new fibre for manufacturing the eco-friendly composite material. Mechanical properties such as tensile strength, shear stress, flexural rigidity, impact strength and hardness of a coconut fibre-reinforced polymer composite material are evaluated as per respective ASTM standards. A surface analysis of the material using a scanning electron microscope is also performed. The results are categorized and tabulated accordingly. The values obtained appear to fall in line with the experimental data and hence can be espoused as an alternative material especially in the automotive sector. [ABSTRACT FROM AUTHOR]

In this study, bamboo and glass fibers were successfully added into bisphenol A–aniline-based benzoxazine resin by hot pressing method. The effect of water absorption on the mechanical properties of the neat benzoxazine and its composites was studied. The composites prepared in this study has been proved to exhibit better water resistance than some conventional natural fiber/polymer composites due to good hydrophobicity of the benzoxazine matrix. From the mechanical tests, the tensile performance of both neat benzoxazine and the composites degraded seriously after prolonged immersion in water. However, neat benzoxazine and the composites maintained relatively higher residual flexural properties (residual mechanical properties refer to the ratio of strength and modulus of the saturated samples to that of the nonaged samples) after 20 days of water immersion. The effect of water molecules on the fracture surface morphologies of the composites was studied using a scanning electron microscope (SEM). The SEM images showed that the interfacial bonding between fibers and the matrix degraded seriously due to the attack of water. [ABSTRACT FROM AUTHOR]

Hybrid matrices (epoxidized of ethylene–propylene–diene monomer (eEPDM) -g- aminopropyltriethoxysilane (APTES)/hydroxyl terminated polydimethylsiloxane (HTPDMS)/polyurethane (PU)) were developed based on eEPDM with 3-APTES coupling agent and varying weight percentages (0.75, 1.50, 2.25, and 3.00 wt%) of PU prepolymer as coreactant using 7.5 wt% of HTPDMS as chain extender using suitable experimental conditions. The formation of hybrid matrices and their structure were characterized by Fourier transform infrared (FTIR). The thermal and morphological properties of the hybrid matrices were analyzed using differential scanning calorimetry and scanning electron microscope, respectively. Mechanical properties (tensile strength, elongation at break (%), Young's modulus, and hardness) were characterized as per ASTM standards. Data resulted from mechanical studies, it was noticed that the incorporation of 3-APTES, HTPDMS, and PU into eEPDM has improved the elongation at break (%) and lowered the values of tensile strength, Young's modulus, and hardness according to the percentage concentration. Morphological studies indicate the presence of heterogeneous morphology. Data obtained from different studies, it suggested that the hybrid matrices developed in the present work can be used as cable insulates for high-performance industrial and engineering applications. [ABSTRACT FROM AUTHOR]

Chemically reduced graphene (C- r GO) nanosheets were first prepared from graphene oxide (GO), and then the polypropylene (PP) composites synergistically reinforced–toughened by styrene–butadiene rubber (SBR), and C- r GO nanosheets were fabricated via melt blending. The mechanical properties of PP can be considerably improved by synergistically filling with C- r GO nanosheets and SBR, especially for the notched Izod impact strength (IS). The results from the X-ray diffraction, polarizing optical micrographs, scanning electron microscope, differential scanning calorimetric, dynamic mechanical analysis, and thermogravimetric analysis measurements reveal that: (1) the β -phase crystal structure of the PP is formed when the C- r GO and SBR are synergistically filled with PP and its formation plays a role for the enhancement of the impact strength for PP/SBR/C- r GO composites; (2) the dispersion of the C- r GO and SBR in the PP/SBR/C- r GO composites is homogeneous, indicating that synergistic incorporating method decreases the aggregation of nanosheets and thus increases the sites for dissipation of shock for impact energy in the PP/SBR/C- r GO composites; and (3) the thermal analysis shows high thermal stability for the PP/SBR/C- r GO composites. [ABSTRACT FROM AUTHOR]

This work deals with the synthesis of biodegradable and UV resistant wood polymer composites (WPCs) via compression moulding technique. As outdoor applications become more widespread, durability becomes an issue. Ultraviolet exposure can lead to photodegradation, which results in a change in appearance and mechanical properties. In this study, we examined the performance of WPCs after UV exposure and microbial attack. The rate of degradation was found to decrease by the addition of a higher percentage of rosin derivatives. The bacterial growth on the samples and morphological features of the bacterial-degraded samples were investigated by UV spectrophotometry and Scanning Electron Microscope (SEM) study, respectively. The UV-degraded samples were also analysed by Fourier Transform Infrared (FTIR) spectroscopy and SEM study. It was observed that with the incorporation of 40 wt-% of divinylacrylicpimaric acid (DAPA) significantly improved the UV stability, mechanical, thermal and other physical properties of the WPCs. [ABSTRACT FROM AUTHOR]

In this study, the effect of polypropylene (PP) as the backbone polymer of Metal injection moulding (MIM) feedstock has been investigated on the micro-structural phase constituents, mechanical and rheological properties of 4605 low alloy steel compacts. For this purpose three binders systems consisting of paraffin wax (PW), stearic acid (SA) and carnauba wax (CW) having different contents of PP (20, 24 and 28 mass %) were compounded. The sintered samples were then tested for mechanical (tensile and hardness), micro-structural (X-ray diffraction (XRD) and scanning electron microscope (SEM)), density and rheological (viscosity) properties. The results show that an increase in the PP percentage results into the improvement of mechanical and physical properties while decreasing the rheological properties. From the microstructure point of view it was observed that the amount of PP, is directly related to the residual carbon content of the sample which affects the grain size, total porosity and phase constituents. [ABSTRACT FROM AUTHOR]

This work investigates the mechanical, fracture toughness, and thermomechanical peculiarity of a novel functionally graded materials (FGMs)–based glass fiber–filled polyamide 66 (PA66) composites. FGMs-based PA66 are fabricated through a particularly designed mold and a punch. Punch is a rotating element of the mold and rotates at 1800 r/min for two min for the fabrication of FGMs. Gradation of fibers takes place in FGMs toward the periphery of the punch cavity due to the centrifugal force. Neat PA66 and homogeneous composites are also fabricated through the same mold for comparative study. Punch remains stationary during the fabrication of neat PA66 and homogeneous composites. PA66 granules filled with 15 wt% and 30 wt% of glass fibers are used to manufacture FGMs and homogeneous composites. Ignition loss test, hardness measurement, and scanning electron microscope (SEM) analysis are used to verify the gradation of glass fibers within FGMs. Result analysis concluded that FGMs performed better as compared to neat PA66 and homogeneous composites. FGMs-based thermoplastic composites have full scope to fabricate polymer gears used in low load applications. This manufacturing route shows a promising potential for fabrication of FGMs-based thermoplastics which otherwise is difficult to manufacture because of their high solidification rate at room temperature. [ABSTRACT FROM AUTHOR]

Response surface methodology (RSM) is used to study the mechanical and morphological properties of glass fiber (GF)/epoxy composites. The Box–Behnken method was used to design the experiments and quantify the effects of GF content, glass fiber length (GFL), and silica nanoparticles (SiO2). Each variable consisted of three levels: GF (5, 10, and 15 wt%), GFL (3, 6, and 9 mm), and SiO2 (0, 0.75, and 1.5 wt%). Tensile tests were performed to obtain the tensile strength and elongation at break of the samples, and morphology properties were studied by a scanning electron microscope (SEM). The results showed that at high levels of GF, the tensile strength, and elongation at break decreased up to 42% and 30%, respectively. Although increasing the GFL from 6 mm to 9 mm deceased tensile strength by 13%, the elongation at break increased by 7%. The presence of SiO2 at medium level in the composites decreased the elongation but enhanced the tensile strength by 10%. In addition, RSM was employed to develop the mathematical model between process variables. The developed models were validated by the analysis of variance. The R 2 obtained from analysis of variance results and normal probability plots showed that the experimental data had a good agreement with those predicted by the models (above 0.95 for all responses). [ABSTRACT FROM AUTHOR]

The present research venture focuses on utilization of food and agricultural waste Citrus limetta (musambi) peel by using it as a filler material to develop novel epoxy (EP) composites. Experimental investigation has been performed to analyse the influence of C limetta (musambi) peel particles (CLPP) on mechanical properties (tensile, flexural and impact strength) of the developed composites. Different loadings by weight percentages (0, 5, 10 and 15 wt%) of filler have been used to explain the variation in mechanical properties. Along with effect of different filler percentages, failure characteristics of the prepared samples have also been studied. The results indicate that higher CLPP content in EP matrix has a detrimental effect on mechanical properties of manufactured biocomposites. Thermal characterization was performed to analyse the degradation behaviour and the onset temperature. Morphological analysis of the fractured surfaces was also conducted with the help of a scanning electron microscope. The current experimental investigation has revealed that CLPP can be used as a potential filler for manufacturing biocomposites with applications in general purpose interior fitments in addition to various non-structural components. [ABSTRACT FROM AUTHOR]

Present investigation elucidates the effect of surface treatment on the mechanical response of carbon fiber (CF)/polyimide (PI) composite loaded with a range of graphene oxide (GO) content. Incorporation of 0.5 wt% GO in CF/PI exhibited 21.1% improvement in flexural strength. The state of interface and its impact on the tensile behavior at various testing temperatures have been discussed. Scanning electron microscope (SEM) analysis of fractured surfaces has been carried out to comprehend various interfacial strengthening and failure micromechanisms. Surface-treated CFs were incorporated into PI matrix to fabricate a high-performance multiscale composite. To improve the stress transfer between PI and CFs, GO was also grown on fibers to produce GO-grown short CFs. The synergic reinforcing effects of combined fillers were analyzed on the fracture surface of composites through SEM. [ABSTRACT FROM AUTHOR]

Theoretical and experimental studies on the compressive mechanical behavior of 4-harness satin weave carbon/epoxy composite laminates under in-plane loading are conducted over the temperature range of 298–473 K and the strain rate range of 0.001–1700/s in this article. The stress–strain curves of 4-harness satin weave composites are obtained at different strain rates and temperatures, and key mechanical properties of the material are determined. The deformation mechanism and failure morphology of the samples are observed and analyzed by scanning electron microscope (SEM) micrographs. The results show that the uniaxial compressive mechanical properties of 4-harness satin weave composites are strongly dependent on the temperature but are weakly sensitive to strain rate. The peak stress and elastic modulus of the material have the trend of decrease with the increasing of temperature, and the decreasing trend can be expressed as the functional relationship of temperature shift factor. In addition, SEM observations show that the quasi-static failure mode of 4-harness satin weave composites is shear failure along the diagonal lines of the specimens, while the dynamic failure modes of the material are multiple delaminations and longitudinal splitting, and with the increasing of temperature, its longitudinal splitting is more serious, but the delamination is relatively reduced. A constitutive model with thermomechanical coupling effects is proposed based on the experimental results and the increment theory of elastic–plastic mechanics. The experimental verification and numerical analysis show that the model is shown to be able to predict the finite deformation behavior of 4-harness satin weave composites over a wide range of temperatures. [ABSTRACT FROM AUTHOR]

In this study, series of blends were prepared by blending unextracted polyamide-6 (PA6) and thermoplastic ester elastomer (TPEE) in certain ratios. The morphologies, thermal behaviors, and mechanical properties of blends have been investigated. Scanning electron microscope results revealed that the morphology of blends was improved significantly when the content of TPEE is less than 50 wt%. Tensile fracture surface images confirmed reactive compatibilization and stress-induced crystallization in blends. The effect of unextracted PA6 content on the elasticity and tensile strength of blends was also studied, and higher elongation rate at break and breaking strength could be achieved when the content of TPEE is ≥50 wt%. The most interesting finding in this study is that the glass transition temperature for rubber phase of blends shifts to lower temperature and decreases with the increase of unextracted PA6 content at certain ratios range. [ABSTRACT FROM AUTHOR]

The AlFeCoNiCrTi high-entropy alloy (HEA) powders were prepared by high-energy ball milling. The ultrafine-grained WC–HEA and WC–Co-cemented carbides were fabricated through planetary ball milling and heat-pressure sintering. The microstructures and properties of the sintered alloys were compared using scanning electron microscope, X-ray diffraction, mechanical property testing and electrochemical testing. It has been shown that the AlFeCoNiCrTi HEA can be used as a binder for the ultrafine-grained WC-based cemented carbide. The WC–HEA-cemented carbide has better performances than the WC–Co-cemented carbide. The suitable contents of HEA can inhibit the WC grain growth and improve the mechanical properties and corrosion resistance of cemented carbides. [ABSTRACT FROM PUBLISHER]

Natural fibres used as reinforcing materials in polymer matrix composites provide positive environmental benefits with respect to ultimate disposability and best utilization of raw materials. Banana fibre is waste from banana trunks or stems which are abundant in many places in the world. To benefit the environment, agricultural industry as well as other industries, there is a need for development of new usage of agricultural waste. Natural fabric based green composites were prepared by hand lay-up technique with natural woven banana fabric (WBF) and Isophthalic acid based unsaturated polyester resin (UPR) as matrix. The mechanical, dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA) and morphological properties of these green composites were investigated. The WBF were treated with 6% aqueous solution of NaOH. Untreated and NaOH treated fabric surfaces were analyzed by using Fourier transform infrared spectroscopy (FT-IR) and Scanning electron microscope (SEM) studies was carried out to evaluate fabric/matrix interactions. Thermogravimetric analysis of the samples indicated better thermal properties of the alkali treated fibres. The improved fabric--matrix interaction is evident from the enhanced tensile and flexural properties. Reduction in water absorption of alkali treated WBF/UPR composite was observed. The results proved that appropriate alkali treatment of banana fabric improved interfacial adhesion, and in turn mechanical and water absorption properties of the green composite made in this study. [ABSTRACT FROM AUTHOR]

Microcellular injection molding is capable of fabricating light weight, dimensionally stable plastic parts while using less material and energy. Two kinds of blowing agents, namely, supercritical nitrogen and expandable thermoplastic microspheres, were employed to produce foamed polylactic acid parts. The surface characteristics were evaluated with a two-dimensional surface roughness analyzer and a three-dimensional white-light interferometer surface profiler. Through surface roughness comparisons, injection molded American Society for Testing Material tensile test bars with expandable thermoplastic microspheres exhibited better surface quality than their supercritical nitrogen counterparts. The tensile properties of injection molded polylactic acid tensile bars with nitrogen and expandable thermoplastic microspheres at various weight concentrations were investigated. The results showed that the polylactic acid/nitrogen parts possessed a better Young’s modulus and tensile strength. The microstructure on the fractured cross-sectional surfaces was characterized using a scanning electron microscope. As reflected by the testing results, the cell microstructure – such as cell size and cell density, and multi-layered structure with a foamed core sandwiched by skin layers – played an important role in the surface quality and mechanical properties. In addition, while an appropriate expandable thermoplastic microspheres content had a positive effect on the cell microstructure and weight reduction, too high of a concentration of expandable thermoplastic microspheres adversely affected the tensile properties and surface roughness of the microcellular polylactic acid tensile test bars. [ABSTRACT FROM PUBLISHER]

The effects of different particle size of silica (nano—primary particle size 15 nm and micro—primary particle size 28 μm) on the cure, mechanical, and swelling properties of hybrid materials based on brominated copolymer isobutylene isoprene/chlorosulfonated polyethylene rubber blend were studied. The enhancement in mechanical properties was supported by the data on the increased content of cross-link density obtained from swelling and stress–strain analyses. The interactions between rubber matrix and filler were investigated by Fourier transform infrared spectroscopy with attenuated total reflectance extension and scanning electron microscope. Tg of reinforced blend shifted to −26°C and −30°C for nano and micro silica compounds, respectively. [ABSTRACT FROM PUBLISHER]

In this work, the mechanical behavior of sintered waste material of ethylene-propylene-diene-monomer crumb rubber (EPDMCR) is analyzed, optimizing the temperature and compression pressure. The results obtained showed that an increase in temperature and compression pressure gives a significant improvement in the mechanical properties of the material. We later mixed the EPDMCR particles with different percentages of adhesives with the aim of further improving the mechanical performance obtained from the sintered particles. The adhesives used in this study were latex and polychloroprene, and the optimum mechanical performance obtained came from mixes with polychloroprene, using a mix with 50% adhesive. The study was concluded with an analysis of images of the material using a scanning electron microscope (SEM), in order to observe the EPDMCR–adhesive interaction. [ABSTRACT FROM PUBLISHER]

Jute fiber-reinforced polyethylene terephthalate (PET) matrix composite was prepared by compression molding. Tensile strength (TS), tensile modulus (TM), elongation at break (Eb%), bending strength (BS), bending modulus (BM), impact strength (IS), and hardness of the composites (50% fiber by weight) were found to be 56 MPa, 1950 MPa, 5%, 73 MPa, 3620 MPa, 24 kJ/m2, and 97 Shore-A, respectively. After 6 weeks of soil degradation, composites lost 28.5% and 24.6% of their original TS and BS, respectively. Interfacial characterization was performed by scanning electron microscope. [ABSTRACT FROM AUTHOR]

Hydroxyapatite/poly(vinyl alcohol) (HAp/PVA) nanocomposite samples were prepared by two different methods of direct mixing and an in situ biomimetic HAp crystallisation in the presence of polymer. Polymer weight fraction was the variant in both procedures. The prepared samples were characterised with regard to their mechanical properties by performing tensile tests on hot pressed samples. The phase composition and microstructural studies were conducted using X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques. Fourier transform infrared (FTIR) was used to determine possible interaction between polymer and HAp during mineralisation processes. The results suggest that a molecular interaction is operative between the side groups of the polymer and the growing HAp crystallites in the in situ process. The enhanced interfacial interaction between the polymer and the reinforcement material led to improved mechanical properties (i.e. higher tensile strength and strain at failure values) for the composite samples prepared by the in situ procedure. An increase in the young's modulus values with increasing filler content was observed for the composite samples prepared by both processes. However, the increase was less in the samples prepared by the in situ process indicating higher strain at a particular stress level. [ABSTRACT FROM AUTHOR]

A novel nanomanipulation technique has been developed to measure the mechanical properties of single nanoparticles. The principle of this technique is to compress single nanoparticles between two flat surfaces comprising a glass slide and the tip of a calibrated glass cantilever inside the chamber of an environmental scanning electron microscope (ESEM), so that the force being imposed on them and their deformation can be determined by a series of images of the particles and the position of the cantilever. The cantilever is held by a nanomanipulator that has a resolution of 0·5 nm. The novel nanomanipulation technique, and a previously developed micromanipulation technique, were first used to measure the force required to compress single microparticles (ranging from 1 to 3 μm in diameter) of methacrylic acid copolymer Eudragit E100 to different deformations under dry mode conditions, to validate results from the former. Results showed that there is no significant difference in the data obtained using these two techniques, which implies that the new nanomanipulation technique is highly reliable. The new technique was then applied to single polymethylmethacrylate (PMMA) particles ranging from 530 to 950 nm in diameter. They were compressed and held, compressed and released, and compressed to different deformations, and the force imposed on the particles was determined simultaneously. This work demonstrates the feasibility of measuring the mechanical properties of single nanoparticles, and the developed technique can find wide application in mechanical characterisation of different nanoparticles. [ABSTRACT FROM AUTHOR]