Fiber Polymer Composites Research Articles

Effect of tungsten carbide on mechanical and tribological properties of jute/sisal/E-glass fabrics reinforced natural rubber/epoxy composites

Natural fiber polymer composites have been largely used in applications like aerospace, automotive, marine, and other civil structures, where mechanical and tribological properties are of prime consideration. The performance of hybrid composites can be improved by using different natural fibers and adding particulate fillers to them. In this study, mechanical and tribological properties of jute/sisal/E-glass fabrics reinforcing matrix such as natural rubber and epoxy filled with different proportion of tungsten carbide (WC) powder were studied. Mechanical properties like tensile strength, flexural strength, impact strength, and also tribological behavior like two-body abrasive wear of composite were studied. Taguchi technique was employed for wear analysis. Results revealed that there is a significant change in the mechanical properties and enhancement of wear behavior was noticed due to the incorporation of filler (WC) particles.

A Novel Technique to Simulate Reduced Residual Stresses in Laminated Composites Using Nanoparticles

Because of the natural inconsistency of mechanical and thermal properties of fiber and matrix, residual stresses are introduced during the curing process of fibrous polymer composites. Considering high Young’s modulus and negative coefficient of thermal expansion (CTE) of carbon nanotubes (CNTs), incorporation of CNTs into the matrix makes the matrix properties closer to the fiber ones and reduces residual stresses in laminated polymeric composites. In the present research, through a systematic theoretical study, effects of addition of small amounts of CNTs on micro- and macro-residual stresses in carbon fiber (CF)/epoxy laminates were investigated. First, micro-mechanics equations were employed to investigate CNTs effects on CTE and Young’s modulus of CNT/epoxy and CNT/CF/epoxy composites. Then, the micro- and macro-residual stresses were calculated using the energy method and classical lamination theory (CLT), respectively. The results indicate that addition of low amounts of the CNT causes the matrix CTE to decrease and the matrix Young’s modulus to increase, which in turn leads to a considerable reduction in micro- and macro-thermal residual stresses.

Analysis of stress concentrations in transversely loaded steel-fiber composites with nano-reinforced interphases

Continuous steel fiber polymer composites are susceptible to high stress concentrations under transverse loading. This is due to the high mismatch in elastic properties of steel fiber and polymeric matrix. In the present work, the effect of a nano-reinforced interphase on the stress concentrations is evaluated. Three types of nano-reinforcements are considered: 1) carbon nanotubes (CNTs) grown on fibers and 2) graphene nano-plates deposited on the fiber surface and 3) graphene nano-plates randomly distributed in the matrix. The study is carried out using finite element (FE) analysis with an intermediate homogenization step to obtain elastic properties of the nano-reinforced interphase. These properties are calculated using an inclusion based approach. Results indicate that the presence of the nano-reinforced interphase increases radial stress concentrations and those in the direction of the load. The suppression is only observed for shear stress concentrations in the case of the CNT interphase around the fibers.

Synthesis and Wear Characterization of Reinforced Glass Fiber Polymer Composites with Epoxy Resin Using Granite Powder

Recent research scenario reveals that the amalgamations of micro and nanoceramic fillers into fiber reinforced polymer composites have improved their performances in an excellent manner. In this research work, an investigation was attempted at in analyzing the wear behavior of glass fiber reinforced with epoxy resin using granite powder as a filler material in varying weight percentage ranging from 0-5%. Structural morphology of the prepared laminates was studied using SEM. Epoxy resin which was taken as matrix material was reinforced with a combination of chopped and woven roving mat glass fibers. Pin on disc method was applied for completing the wear test at different constraints of load, sliding distance and velocity for the investigation. Influence of granite powder in the composite was synthesized by calculating the specific wear rate and weight loss occurring at varying speed and normal load were applied on it. On examining by SEM worn surface wear rate of the prepared laminate at 5 wt% of granite provided better wear resistance as compared to other compositions and characterizations of worn surfaces.

Investigation on Mechanical Properties of Coir Fiber Reinforced Polymer Resin Composites Saturated with Different Filling Agents

The main objective of this research article is to assess the mechanical properties and fracture analysis of bone and sea shell powders independently integrated with coir fiber polymer composites. The specimen was fabricated with coir fiber at various dimensions of coir fiber like diameter, length, content and mesh size of the powder. Tensile, compressive, flexural and impact tests were conducted in the prepared composite materials as per the techniques of ASTM standard. The fracture faces were explored with the help of SEM images. From the final results it was concluded that the sea shell powder composite provides good tensile and flexural strength than bone powder composite, while bone powder composite material gives good compressive and impact strength than sea shell powder composite material.

Fabrication of Magnetic Polymer Composite Sorbents and its Application for Recovery of Platinum from Acidic Solution

Magnetic MnFe2O4 nanoparticles (MNPs) were fabricated and entrapped in amine-rich chitosan (CS) sorbents containing multi-walled carbon nanotubes (MWCNTs) or polyethyleneimine (PEI). Magnetic polymer composite sponges (MPCSs) and magnetic polymer composite fibers (MPCFs) were prepared through mixing each of MWCNT and PEI with MNPs-CS solution. The successful fabrication of MPCSs and MPCFs was confirmed through FTIR and VSM analyses. The as-fabricated MPCSs and MPCFs were used for adsorptive recovery of Pt (IV) from acidic solution. The maximum uptakes of Pt (IV) ions by the MPCSs and MPCFs were estimated to be 218.2 ± 8.3 and 371.4 ± 16.8 mg/g, respectively. Moreover, the Pt (IV)-loaded MPCSs and MPCFs were easily separated from aqueous solution under magnetic field after sorption process.

Controlling the electrical conductivity of fibre-polymer composites using z-pins

Carbon fibre composites have inherently high through-thickness electrical resistivity, which limits their application when high electrical conductivity is required. The use of z-pins to increase the through-thickness electrical conductivity of composite laminates is investigated in this paper. The through-thickness and in-plane electrical properties of a unidirectional carbon-epoxy laminate reinforced with carbon fibre composite or metal (copper, stainless steel, titanium) z-pins are characterised. Experimental tests and analytical model reveal that z-pins can increase the through-thickness electrical conductivity of the composite material by many orders of magnitude (up to 106). The through-thickness electrical conductivity can be controllably increased via the judicious choice of the material type and volume content of the z-pins. Large improvements to the through-thickness conductivity can be achieved without the z-pins altering significantly the in-plane conductivity of the composite material.

Wettability of carbon nanotube fibers

Carbon nanotube (CNT) fibers are interesting alternatives to carbon fibers as fibrous reinforcement. However, good interfacial adhesion between the fibers and the matrix is difficult to control. Wetting of the fiber reinforcement with the matrix strongly determines the interfacial strength. Therefore, accurate characterization of the wettability of CNT fibers is one of the most important cornerstones to improve the interfacial adhesion. In this work, dynamic contact angle measurements were conducted on individual CNT fibers by using a modified tensiometric method based on the Wilhelmy method combined with a synchronized optical observation. The CNT fiber-liquid interactions were monitored in-situ, and accurate measurements of the contact angles were achieved. Contact angles on CNTs were estimated through a modified Cassie-Baxter model on the basis of the experimental contact angle values of CNT fibers. Subsequently, the non-polar and polar surface energy components of the CNTs were obtained. Then, the wetting parameters (work of adhesion, spreading coefficient and wetting tension) were predicted by using the surface energy values of both the CNTs and a series of polymers (PP, MAPP, PET, PVDF, and PVA). The results indicate that PVA is in terms of wetting the most suitable matrix for the preparation of CNT fiber polymer composites.

Development of reinforced composite materials with a nanoporous textile substrate and a brush-structured polymer interfacial layer

A method for controlling the elastic deformation properties of polymer‒fiber composites was developed. The rigidity of the material is increased by the penetration of the reinforcing polymer into the pore structure of the textile substrate to form а branched interfacial layer. The nanoparticle size distribution in the polymer hydrosol products was analyzed by dynamic light scattering, the porosity of fibrous materials was measured by low temperature of adsorption and desorption of nitrogen vapor, and the polymer‒polymer interactions were studied by IR spectroscopy and differential scanning calorimetry. The method was implemented in the development of a new range of garment interfacings and allowed solution of engineering problems associated with imparting to garments a complex geometric shape and its retention in wear.

Fibridization Effect on the Mechanical Behavior of PA66/PTFE Blend Based Fibrous Composites

The use of natural fiber along with the glass fiber in polymer composites is one of the present material combinations for automotive industries. This article deals with the hybrid effect of 10 wt% short glass fibers (SGF) and 10 wt% short basalt fibers (SBF) on the mechanical behavior of 80 wt% PA66/20 wt% Teflon (PA66/PTFE) blend. These composite materials were prepared by melt mixing method, by using twin screw extruder followed by injection molding. The mechanical performance of the composite materials was tested as per ASTM method. The experimentally determined mechanical properties were tensile behavior, flexural behavior and impact behavior. Hardness and density of the blended composites were also studied. Experimental results revealed that the effect of hybrid short fibers on the blend greatly enhanced the mechanical behavior. Increase in tensile strength and flexural strength by 33% and 57% respectively and 6% reduction in elongation was exhibited by the blend due to the hybrid effect of fibers. The synergistic effect between the fibers and the matrix blend improved the mechanical behavior. The strain rate of the hybrid composites was deteriorated due to the hybrid effect. The enhancement of load carrying capacity by 17.35, 8.5 and 36% was exhibited by SGF, SBF and hybrid fiber filled PA66/PTFE blend composites respectively. The impact strength of the hybrid composites was reduced due to the brittle nature of the hybrid filled composites. Fiber fracture, fiber pull out and fiber misalignment were the certain mechanisms observed during mechanical performance. The fractured surfaces were analyzed through Scanning Electron Microscopy photographs.

Characterization of Willow Bast Fibers (Salix spp.) from Short-Rotation Plantation as Potential Reinforcement for Polymer Composites

Short-rotation coppices have potential to be the future source of raw materials for many applications in the wood and paper industries. It is important to establish methods and products to handle their waste biomass. In this paper, the properties of bast fibers extracted from the bark of willow trees (Salix spp.) were evaluated for potential future use in the production of natural fiber-polymer composites. The anatomy of the fibers was investigated through optical and electron microscopy. The thermogravimetric analysis of these fibers showed that the major mass loss occurs at 257 °C. The density of the fibers was measured with a gas pycnometer (1.19 ± 0.2 g/cm3). The chemical analysis showed that willow bark fibers have a composition similar to willow wood. As an indicator of mechanical properties, single willow bast fibers were characterized by tensile tests. The results revealed values for tensile strength (307.6 ± 130.1 MPa) and Young’s modulus (16.9 ± 8.4 GPa) that are comparable to some commonly used natural fibers. The overall results showed that willow bast fibers have the required mechanical properties as well as thermal stability for application in reinforcement of polymers.

Modelling the effect of temperature on the probabilistic stress–life fatigue diagram of glass fibre–polymer composites loaded in tension along the fibre direction

Predicting the fatigue performance of composites has proven to be a challenge both conceptually, due to the inherent complexity of the phenomenon, and practically, because of the resource-intensive process of fatigue testing. Moreover, mechanical behaviour of polymer matrix composites exhibits a complicated temperature dependence, making the prediction of fatigue performance under different temperatures even more complex and resource intensive. The objective of this paper is to provide a method for the prediction of fatigue life of glass–polymer composites loaded in the fibre direction at various temperatures with minimal experimental efforts. This is achieved by using a static strength degradation approach to fatigue modelling, where only two parameters (including static strength) are temperature dependent, in conjunction with relationships for these two fatigue model parameters temperature dependence. The method relies on fatigue data at a single temperature and simple static tests at different temperatures to predict the effects of temperature on the material’s fatigue behaviour. The model is validated on experimental data for two unidirectional and one woven glass–epoxy composites and is found to accurately predict the effect of temperature on fatigue life of composites. A method to obtain probabilistic stress-life [Formula: see text] fatigue diagrams including temperature effects is also presented.

Influence of Distinct Environment on the Mechanical Characteristics of Arhar Fiber Polymer Composites

Over the past decades the need for eco-friendly, non-toxic and biodegradable material is growing significantly. Natural fiber polymer composites have become the prior choice for many applications, as the natural fiber polymer composites are economical and eco-friendly materials in contrast with synthetic fiber reinforced composites. In the current study arhar fiber is used as a reinforcing material. Arhar fiber epoxy composites are fabricated using the hand lay-up technique. The materials were tested for weight gain in different environments (saline water, mineral water and subzero temperature condition). The composite samples immersed in the different environments were tested for tensile strength. It is observed that weight gain is more in mineral water and saline water, minimum weight gain is observed in subzero condition. Maximum tensile strength is observed in 10%fiber content samples. Strength depreciation ismore in samples immersed in the saline water environment.

Application of Analytic Hierarchy Process (AHP) in the analysis of the fuel efficiency in the automobile industry with the utilization of Natural Fiber Polymer Composites (NFPC)

A systematic method of material analysis aiming for fuel efficiency improvement with the utilization of natural fiber reinforced polymer matrix composites in the automobile industry is proposed. A multi-factor based decision criteria with Analytical Hierarchy Process (AHP) was used and executed through MATLAB to achieve improved fuel efficiency through the weight reduction of vehicular components by effective comparison between two engine hood designs. The reduction was simulated by utilizing natural fiber polymer composites with thermoplastic polypropylene (PP) as the matrix polymer and benchmarked against a synthetic based composite component. Results showed that PP with 35% of flax fiber loading achieved a 0.4% improvement in fuel efficiency, and it was the highest among the 27 candidate fibers.

Comparative assessment of the explosive blast performance of carbon and glass fibre-polymer composites used in naval ship structures

An experimental investigation is presented into the explosive blast response of fibre-reinforced polymer laminates used in naval ship structures. Blast tests using plastic explosive charges were performed in air on square target plates made of carbon-polyester, glass-polyester, carbon-vinyl ester or glass-vinyl ester laminates, which are composite materials used in naval ships. The laminates were dynamically loaded by shock waves of increasing pressure and impulse, and the deformation, damage and residual mechanical properties were determined. The amount of blast-induced damage and the post-blast mechanical properties depend on both the fibre reinforcement and polymer matrix. E-glass laminates have higher resistance to blast-induced delamination cracking and tow rupture than carbon fibre composites. Furthermore, glass or carbon fibre laminates with a vinyl ester matrix have superior blast damage resistance compared to composites with a polyester matrix. The higher damage resistance is attributed to the higher flexural strain energy capacity and interlaminar fracture toughness properties of laminates containing glass fibres or vinyl ester matrix.

Finite element estimates of viscoelastic stiffness of short glass fiber reinforced composites

An unstructured mesh Galerkin finite element method is used to obtain estimates of the viscoelastic moduli of short glass fiber reinforced polymer composites. Periodic Monte Carlo models with 125 identical inclusions are studied. Both spheroidal and spherocylindrical inclusions are considered. The estimates are compared against predictions of the dilute approximation, Mori-Tanaka (MT) and self-consistent (SC) models. It is shown that at small fiber fractions, the dilute approximation (Eshelby) model is exact. However, for the axial stiffness the dilute regime is limited to fiber volume loadings of a few tens of a percent while typical short glass fiber polymer composites have fiber loadings from 10 to 20 percent. It is found that in this concentrated regime, both MT and SC models give excellent predictions for all but the axial stiffness modulus. To assess the feasibility of reliable stiffness and vibration damping design of composite structures from short fiber reinforced polymers, Monte Carlo models with various fiber orientation distribution (FOD) states are studied. It is shown that the quick Voigt (constant strain) orientation averaging procedure gives excellent viscoelastic stiffness predictions provided that the finite element estimates are used for the required moduli of the basis FOD state with fully aligned fibers.

Wear rate and surface coating optimization of coconut coir-based polymer using fuzzy logic

The use of fuzzy logic for modeling surface parameters of coconut coir-based composite is the focus of this research paper. Natural fiber–polymer composite has been developed by combining coconut coir as a stimulator and polyester as a fixative. This sturdy material is resistant to scratches in the coating process on the surface layer of composite material. The specimen of this composite material is fabricated by different coir fiber and resin content. A polyurethane coating is also applied with varied thickness to give better wear rate and surface coating properties. A fuzzy logic approach is adopted to invent the optimal wear rate and surface coating using coating thickness and fiber content properties. The results indicate the best combinations of coating thickness and its surface roughness of the sandwiches. MATLAB 7 is used in this work.

Reinforcement effect of graphene oxide in glass fibre/epoxy composites at in-situ elevated temperature environments: An emphasis on graphene oxide content

The unique and exceptional properties of graphene based nanofillers have impelled material scientists for their possible exploitation in fibrous polymeric composites. Present investigation elucidates the effect of environmental temperature on the mechanical response of glass fibre/epoxy (GE) composite loaded with a range of graphene oxide (GO) content. Incorporation of 0.5wt.% GO in GE exhibited 21.1% improvement in flexural strength. The state of interface (both GO/epoxy and glass fibre/epoxy) and its impact on the flexural behaviour at various testing temperatures has been discussed. The viscoelastic properties of all the materials have been further evaluated in the temperature range of 40–200°C. The Weibull design parameters have been analysed as a function of GO content and testing temperature. Scanning electron microscope (SEM) analysis of fractured surfaces has been carried out to comprehend various interfacial strengthening and failure micro-mechanisms.

Acidochromic fibrous polymer composites for rapid gas detection

Electrospun spiropyran-embedded nanofibers for fast photocontrollable and reversible optochemosensing of acidic vapors.

Experimental investigation on Tensile property of Ricinus Communis L plant fiber to make polymer reinforced composites

Day by day demand has been increasing for light weight, high strength, high stiffed and eco-friendly composites in many engineering applications like Automobile, Aerospace, Structural etc. Natural fiber polymer composites are best suitable for making of light weight, high strength, stiffness and eco-friendly composites. Many engineers and researchers are working for the development and improvement of natural fiber reinforce polymer composites. The present work aims at introducing new natural fiber as reinforcement in polymer matrix. The method of fiber extraction is also presented. Cortex (Bark fibers) and Xylem (wood type) fiber of castor oil plant (Ricinus Communis L) are extracted. The tensile properties of single cortex fiber and single xylem fiber are tested as per the ASTM standards. The tensile strength of (323 MPa for 300 µm (0.3mm) diameter) single castor oil plant cortex fiber is comparatively very high as with the tensile strength (100 MPa for 300 µm (0.3mm) diameter) of the single castor oil plant xylem fiber. The preliminary studies of the fiber revealed that the fiber can be used as reinforcement for natural fiber composites.