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Carbon nanofibers (CNFs) were coated by surfactants of polyoxyetheylene alkyl ether (AEO₉, AEO₇) and polyvinyl alcohol (PVA 1799), respectively, after being mixed with surfactant aqueous solution and then treated with ultrasonication, high shear and magnetic stirring. The CNF/epoxy composites were prepared by mixing the surfactant coated CNFs with epoxy. Tensile strength, elastic modulus and ultimate strain of the composites were studied. The tensile strength and the ultimate strain of the composites were increased by 20% and 70%, respectively, after the CNFs were coated by surfactants. However, the elastic modulus of the composite will be lowered when the CNFs were treated by too high a concentration of surfactant solution.

In this study, Sn-Ag-Cu based nanocomposites with carbon nanotubes (CNTs) as reinforcements were successfully synthesized via the powder metallurgy technique. Lead-free solder powders were firstly blended together with varying weight percentages of CNTs. The materials were then compacted, sintered and finally extruded at room temperature. The extruded materials were characterized for their microstructural, thermal and mechanical properties. The porosity of the nanocomposites was observed to increase with increasing weight percentages of CNTs, accordingly the density of the nanocomposites was reduced. Thermomechanical analysis of the solder nanocomposites showed that the use of CNTs as reinforcements decreased the average coefficient of thermal expansion of the solder matrix. Furthermore, the results of mechanical properties characterization revealed that the addition of CNTs aids in enhancing the microhardness and the overall strength of the nanocomposite solder. An attempt is made in the present study to correlate the variation in weight percentages of the carbon nanotubes with the properties of the resultant nanocomposite materials.

The study of crack propagation in rubber has a very high economic significance but is still not well understood. For this purpose the main objective of this work is to study the fracture behavior of two types of rubber: the NR, which crystallizes under stress and the noncrystallizing SBR. To study the cracking behavior of materials we have made tests of cracking follow-up. The mode of crack propagation has been studied in terms of fillers ratio and traction speed. The unfilled SBR and NR showed simple lateral propagation independently of the test speed, whereas the mode of cracking of filled materials was very influenced by the parameters mentioned previously. The filled SBR can present important deviations of the crack when the fillers ratio is sufficiently high; this deviation is even more pronounced when the speed increases. On the other hand, the natural rubber which crystallizes under stress showed particular mode of propagation characterized by the appearance of longitudinal cracks. This mode of cracking is much more important at low speeds than at the high speeds. It is proposed that the fillers increase the breaking strength of a noncrystallizing material and allows that the crack takes a deviated way if the fillers ratio is sufficiently high. But if it is a material which crystallize like the NR, crystallization and fillers will act simultaneously and the material will be much more resistant which gives rise to a particular mechanism which is the appearance of the longitudinal cracks before the catastrophic rupture.

This research aims to study the addition of nanoclays on unsaturated polyester (UP) and epoxy resin (EP) as filling and by weight percentage (2%, 4% and 6%) to this mixture and then study the extent of the effect of this addition on wear rate of the composites’ material where three loads were adopted (10, 15 and 20N), respectively, on the iron hard disk (269 HB) and copper hard disk of 111HB for the resin before and after adding the clays, where the approved sliding velocities were 4.1887, 3.1415 and 2.0943m/sec, respectively, and the test duration was 10 min on the test disc. Immersion of samples in the water for 2, 4, 6 and 8 weeks showed a clear improvement in the wear rate and tear values of dry and submerged conditions in a water under different conditions of load change, slipping speed, time and temperature stability after adding the nanoclays to the polymer.

The paper presents an overview of multiscale modeling of advanced fibrous composite materials. Following the review, a nonlinear, fully three-dimensional, numerical model is proposed which is suitable for multiscale elastic and progressive failure analysis of plain-woven composite materials. The proposed model is developed for implementation into the Finite Element code ABAQUS/Explicit as a user-defined subroutine for constant stress (one integration point) solid elements.

The multiscale strategy applied in this paper uses a closed-form solution approach for homogenization of the mesoscale properties of a woven composite. A mosaic model of the woven composite's Representative Volume Element (RVE) is used for deriving the micromechanical relations used for homogenization. The composite RVE model used herein is composed of UD interlacing yarns (fill and warp yarns) and matrix-rich regions. For failure and damage analysis, the following features are implemented in this work: material nonlinearity for pure in-plane shear deformation; physically-based failure criteria for matrix failure in the UD yarns; maximum stress failure criteria for failure of fibers in the UD yarns and of the pure matrix in the resin-rich regions and energy-based damage mechanics.

The proposed strategy, which has been implemented and tested for a special case of an in-plane damage, has some evident advantages compared to the other approaches, especially for application to full-scale simulations, i.e., component and structural scales.

A comparison of the proposed model with experimental data shows a good correlation can be achieved.

Advanced composites are increasingly being used as a structural material because of their balanced properties, higher impact resistance, and easier handling and fabrication compared with unidirectional composites. However, complex architecture of these composites leads to difficulties in predicting the mechanical response necessary for product design. Different methods for micromechanical analysis for the evaluation of effective mechanical properties of advanced composites are compared. Difficulties in modeling are highlighted and recommendations are given for micromechanical analysis using the finite element method.

The present study deals with both experimental and numerical investigation on vibration behavior of laminated composite plates subjected to varying temperature and moisture. Extensive experiments are carried out for free vibration analysis of woven fiber Glass/Epoxy composite plates under hygrothermal conditions. The specimens were hygrothermally conditioned in a humidity cabinet where the conditions were maintained at high temperatures and moisture concentrations.

A recently proposed criterion is used to study the behavior of debonds produced at a fiber–matrix interface. The criterion is based on the Linear Elastic–(Perfectly) Brittle Interface Model (LEBIM) combined with a Finite Fracture Mechanics (FFM) approach, where the stress and energy criteria are suitably coupled. Special attention is given to the discussion about the symmetry of the debond onset and growth in an isolated single fiber specimen under uniaxial transverse tension. A common composite material system, glass fiber–epoxy matrix, is considered. The present methodology uses a two-dimensional (2D) Boundary Element Method (BEM) code to carry out the analysis of interface failure. The present results show that a non-symmetrical interface crack configuration (debonds at one side only) is produced by a lower critical remote load than the symmetrical case (debonds at both sides). Thus, the non-symmetrical solution is the preferred one, which agrees with the experimental evidences found in the literature.

Fibers are structurally interesting components most useful in a range of applications spanning the physical and life science areas of research. These membrane (scaffold) forming fibers have been explored in applications ranging from microfilteration to advanced biological investigations in tissue engineering to controlled and targeted drug delivery. One such robust fiber generation approach investigated for over a century, which has recently been exploited, is the well-established threading process referred to as electrospinning. In this technique, single- or multi-phase media are charged within a conducting needle and later exposed to an electric field which promotes the formation of a continuous micro- to nanosized fiber(s) which over a period of collection time has been reported for forming scaffolds and membranes. This process has been explored for a wide range of polymer composite-based materials and the technique has now reached the point where it has moved into industrial production. We report here as a first example a comparable fiber to membrane fabrication approach completely driven by the coupling of a coaxial needle system with a pressure. We refer to this novel methodology as pressure-assisted spinning (PAS) where the hazardous element of high voltage (as in the case of electrospinning) is nonexistent. Hence, our discovery introduces both a directly competing fiber, scaffold to membrane fabrication approach, which is versatile and has no associated hazards as those in electrospinning. Furthermore as our technique is nonelectric field driven, the media spun into fibers could have a high electrical conductivity, which in this case has no effect on the stability in processing near-uniform fibers/scaffolds to membranes. The fabricated fibers and membranes generated by means of this approach could directly be used for a plethora of applications spanning the engineering and biological areas of research.

A thermotropic liquid crystalline polymer (TLCP) was synthesized from 4, 4'-Oxobisbenzoic acid and methylhydroquinone by low-temperature solution polycondensation. Nanocomposites of TLCP with the content of MWNTs from 0 wt% to 10 wt% were prepared by in situ polymerization. Scanning electron microscopy images showed that the MWNTs were well-separated in the TLCP matrix. Differential scanning calorimetry, thermogravimetric analyzer, X-ray diffraction, and polarized optical microscopy were used to investigate the thermal behavior, crystalline structure and liquid crystalline properties of the pure TLCP and TLCP/MWNT nanocomposites. The thermogravimetric analyses indicated that a small amount of MWNTs could improve the thermal stability of TLCP matrix. Furthermore, the result of differential scanning calorimetry demonstrated that both melt transition temperatures and isotropic transition temperatures of the hybrids were enhanced. Our study provided a design guide for CNT-filled TLCP composites which could be favorable for industrial use.

Owing to the unique microstructure and the excellent dielectric properties, carbon nanotubes (CNTs) were decorated with CoFe₂O₄ nanoparticles to synthesize the CoFe₂O₄/CNTs nanocomposites by the solvothermal method. The phase structure, morphology, magnetic properties and microwave absorption performance of the as-prepared CoFe₂O₄/CNTs were characterized and discussed by X-ray diffraction (XRD), thermal gravity analysis (TGA), transmission electron microscope (TEM), vibrating sample magnetometer (VSM) and vector network analyzer (VNA). All results indicated that the diameter of CoFe₂O₄ nanoparticles decorating on the surface of CNTs increased with the solvothermal temperature. CoFe₂O₄/CNTs prepared at 180°C, 200°C and 220°C exhibited superparamagnetism, while the other samples presented ferromagnetism at room temperature. And with the increasing solvothermal temperature, the saturation magnetization and coercivity increased up to 72 emu/g and 2000 Oe for the sample prepared at 260°C (S-26). And the reflection loss of CoFe₂O₄/CNTs nanocomposites increased with the solvothermal temperature up to -15.7 dB for S-26 with the bandwidth of 2.5 GHz.

In this work, Ni-doped ZnO/Al composites were prepared by a facile chemical co-precipitation method. The morphology and structure of the as-prepared composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), respectively. It was found that the flake-like Al powders were successfully coated by Ni-doped ZnO nanoparticles with slight aggregation and Ni${}^{2+}$ was successfully doped into the crystal lattice of ZnO. Moreover, the effects of ZnO concentration and doped Ni concentration on the infrared emissivity of ZnO/Al composites at the waveband range of 8–14$\mu$m were studied. The results showed that the ZnO/Al composites exhibited the lowest infrared emissivity of 0.34 with 50wt.% ZnO concentration. Meanwhile, the electromagnetic parameters and microwave absorbing properties of Ni-doped ZnO/Al composites in the frequency range of 2–18GHz were explored. Significantly, 12mol.% Ni-doped ZnO/Al composites presented the lowest infrared emissivity of 0.37 and the maximum reflection loss reached $-$32.5dB at 13.6GHz with a thickness of 4.5mm. The excellent microwave absorbing properties could be attributed to the good impedance match, crystal lattice defects and interfacial polarization. It was believed that the Ni-doped ZnO/Al composites could be used as potential infrared-microwave compatible stealth materials.

Polyvinyl alcohol (PVA) was grafted on graphene nanosheets (GN) in the reduction of graphene oxide with hydrazine hydrate. The obtained GN-PVA (GP) suspension was treated with the freezing–thawing cycle to fabricate 3D porous monolithic GP materials, which were modified with carbon disulfide to introduce xanthan groups on the wall of porous materials, marked as GPCs. The characterization of GPCs confirmed that PVA was attached on the surface of GNs, and xanthan groups were effectively functionalized on the porous structures, which were composed of randomly oriented GNs. The Pb${}^{2+}$ adsorption pattern for GPC materials was investigated. The kinetic adsorption and isotherm data fit the pseudo second-order kinetic and the Langmuir isotherm models, respectively. The maximum adsorption capacity of Pb${}^{2+}$ reached 242.7mg/g. And GPCs for Pb${}^{2+}$ adsorption could be regenerated with ethylenediamine tetracetic acid (EDTA) solution for repetitious adsorption.

The properties of fiber-matrix interface pay an important effect on the mechanical properties of carbon fiber-reinforced composites. To improve the interfacial properties in carbon fiber/phenolic resin (CF/PF) composites, CF adhered CNTs (CNTs-CF) were prepared by CVD method. The surface of treated CF and the distribution of CNTs in the interfacial region of CF were detected by scanning electron microscopy (SEM). SEM images identified 700${}^{\circ }$C being the optimum growth temperature to obtain CNTs-CF, in which CNTs randomly dispersed surrounding the individual fiber surfaces. Compared to crude CF/PF composites, the tensile strength, bending strength, shear strength, impact strength, thermal conductivity at 25${}^{\circ }$C of CNTs-CF/PF composites increase by 144.5%, 59.2%, 129.0%, 75.9% and 41.7%. The improvement of mechanical properties is due to that the homogenously dispersed CNTs serve as a supplementary reinforcement to the interface and further reduce inter-laminar stress concentration. This represents an important step toward CNT-reinforced polymers with high mechanical properties.

In this work, graphene aerogels (GAs) with three-dimensional interconnected networks were prepared by chemical reduction and self-assembly of graphene oxide sheets. After microwave treatment, obtained microwave reduced graphene aerogels (MRGAs) were used in the preparation of bismaleimide (BMI) composites. The results show that the microwave treatment significantly enhanced the quality of GAs, and the three-dimensional networks in the GAs were well retained. Moreover, the MRGAs were highly efficient in endowing BMI with high electrical conductivity and excellent electromagnetic interference shielding effectiveness (EMI SE). The conductivity of MRGA/BMI composites was 42–68% higher than that of GA/BMI composites. When the filler content is 1.6 wt.%, the EMI SE of MRGA/BMI composite was 32.3% higher than that of GA/BMI composite in the X band.

In this paper, various research works have been performed on synthesis and functionalization after the invention of graphene (Gr) and its spectral properties. The reinforcing of Gr family members into the matrix leads to the development of novel composites. Its characterization in terms of morphological and physicochemical properties is required for the discovery of wide-ranging applications. This paper reviews the various emerging features and future scope for reduced graphene oxide (rGO). The possibilities of composites development through the different matrix are proposed to evaluate application potential, various fabrication techniques for Gr, and its role in improving composite properties. The work initially examines multiple ways to synthesize rGO. Its addition to different materials includes metals, metal oxides, ceramics, polymers, and organic compounds through various composite preparation techniques. Finally, this paper gives an overview of the enhancement in properties obtained due to the addition of rGO, which opens the door for a broad set of applications. This paper concludes with a comparative study that defines a suitable preparation technique according to the required material composites, desired properties, and specific applications. An attempt has been proposed to examine the exceptional feature of rGO/composite for cost-effective functions in manufacturing sectors.

Interlaminar delamination and brittle fracture of matrix have been a dilemma that fiber-reinforced composites have been faced with. Herein, the polyimide (PI) nanofiber-toughened glass fiber fiber-reinforced epoxy composites were prepared by electrospinning method and subsequent vacuum assistant resin transfer molding. The effect of spinning parameters including PI concentration, applied voltage, collector distance, jet speed and ambient humidity on the resultant fiber diameter and its distribution was systematically evaluated. The surface properties of obtained PI nanofibers were characterized by FT-IR, TG-DSC and water contact angle. The effect of PI concentration on tensile strength of PI membranes was also studied. The mode I (G${}_{\mathrm{\text{Ic}}})$ and mode II (G${}_{\mathrm{\text{IIc}}})$ interlaminar fracture toughness were measured. The results indicated that G_Ic and G_IIc increased by 127.69% and 85.33%. The improvement of interlaminar fracture toughness may be attributed to the bridging effect of PI nanofibers.

In this paper, we have developed self-assembled nanoscale assemblies that were prepared by conjugating furan-2-carboxylic acid-3-aminopropyl amide with the short peptide sequence Gly-His (abbreviated Gly-His-FCAP). To mimic the extracellular matrix of mammalian fibroblasts and keratinocytes, the assemblies were then conjugated with Type I collagen. We then integrated the collagen bound Gly-His-FCAP assemblies with a short peptide sequence derived from salamander skin into the nanoscale assemblies for the first time to impart regenerative and wound healing properties to the composites. The antioxidant, antimicrobial and biodegradable properties were examined and results indicate that the nanocomposites displayed antioxidant properties as displayed by 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The biodegradability was found to be gradual. The nanocomposites were also found to inhibit the growth of the fungus Rhizopus sporangia over an 18h growth period. As proof of concept, to demonstrate the development of three-dimensional (3D) engineered skin in vitro, 3D printed PLA scaffolds of 2.5mm thickness were submerged in media containing nanocomposites and co-cultures of dermal fibroblasts with epidermal keratinocytes mimicking three dimensional skin substitute was examined. Our results indicated that the nanocomposites adhered to and supported cell proliferation and mimicked the components of skin and may have potential applications in skin tissue regeneration.

The influence of the thermal residual stress and reinforcement geometry on the creep behavior of a composite disc has been analyzed in this paper. The creep analysis in a rotating disc made of Al-SiC (particle/whisker) composite having hyperbolically varying thickness has been carried out using anisotropic Hoffman yield criterion and results obtained are compared with those using Hill's criterion ignoring difference in yield stresses. The steady state creep behavior has been described by Sherby's creep law. The creep parameters characterizing difference in yield stresses have been used from the available experimental results in literature. It is observed that the stresses are not much affected by the presence of thermal residual stress, while thermal residual stress introduces significant change in the strain rates in an anisotropic rotating disc. Secondly, it is noticed that the steady state creep rates in whisker reinforced disc with/without residual stress are observed to be significantly lower than those observed in particle reinforced disc with/without residual stress. It is concluded that the presence of residual stress in an anisotropic disc with varying thickness needs attention for designing a disc.

In this paper, an effort has been made to study the effect of anisotropy on the steady state creep behavior in the functionally graded material disc with hyperbolic thickness made of Al-SiC (particle). The content of silicon carbide particles in the disc is assumed to decrease linearly from the inner to the outer radius of the disc. The creep behavior of the disc under stresses developing due to rotation at 15,000 rpm has been determined by Sherby's law. The creep parameters of the FGM disc vary along the radial distance due to varying composition and this variation has been estimated by regression fit of the available experimental data. The creep response of rotating disc is expressed by a threshold stress with value of stress exponent as 8. The study reveals that the anisotropy has a significant effect on the steady state creep response of rotating FGM disc. Thus, the care to introduce anisotropy should be taken for the safe design of the rotating FGM disc with hyperbolic thickness.