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Converting CO2 to valuable materials is attractive in environmental protection and resource utilization. In this study, a vapor–liquid interface reaction system for mass production of high-quality graphene is reported. The graphene obtained has high crystallinity and few defects during the reaction of CO2 and Mg melt. The growth mechanism of graphene is demonstrated in vapor–liquid interface area by combining the CO2 bubbles as a soft template to guide growth with the confinement effect of dense MgO nanoparticles. The quality of the graphene is verified by epoxy composites with high electromagnetic shielding effectiveness. Additionally, the V–L reaction method ingeniously solves the dispersion of graphene in metal, providing a preparation strategy of Mg matrix composites with structure and function integration.

In recent decades, one can observe a great increase in the replacement of traditional materials with polymer composites in high-strength and lightweight applications. High fuel consumption by automobile and aerospace vehicles built from legacy alloys has been a great challenge to material engineers. This has called for researches into lighter material development of the same or even superior mechanical properties to the existing materials in this area of applications. In the present study, epoxy based simple and hybrid composites were prepared with the incorporation of industrial waste as fillers at different weight percentages. Effect of filler type, combination and its concentration on mechanical properties such as tensile, impact and flexural strength were investigated. SEM analysis was carried out for fractured surfaces of composites, wherein minor voids, crack initiations and filler pullouts were seen indicating the necessity of coupling agent addition for still better performance. Among hybrid composites, epoxy/fly ash/red mud/aluminium powder (91/6/1.5/1.5 wt%) has showed the highest ultimate tensile modulus, flexural strength and hardness value compared to other composites under study.

In the design and fabrication of any structural system for space application, balance between mass, stiffness and strength is crucial. Structures in space environments are exposed to high radiation levels and thermal shock, due to the sun irradiance and rotation around Earth. Therefore, accurate determination of the thermal and radiation properties is a key issue for the materials used in such applications. This study reports the thermal and mechanical performance of particle composites (epoxy resin and ZnO particles) after gamma and UV radiation. Composites are exposed to gamma and UV radiation at rates of 1 kGy and 10 kGy and characterized after exposure. For the evaluation, DMA, TGA and three-point bending mechanical test are performed to determine thermal properties and possible material degradation after radiation exposure. The incorporation of the filler in the thermal, radiation and mechanical response of the epoxy system improves as a function of its concentration. Then, epoxy resin reinforced with ZnO particles can be a potential candidate as a polymeric matrix for fiber-reinforced composites for nanosatellites.

The mechanical properties of two commercial epoxides have been investigated in both unfilled and filled with varying the weight fraction of Nano Aluminum powder and Nano Aluminum with Nano Titanium powder. The values of Young’s modulus, modulus of rigidity, yield stress, tensile strength, flexural strength have been studied at room temperature to identify the specific influence of Aluminum powder (the particle size for Aluminum powder is less than or equal to 50 nm (d ≤ 50). The weight fraction has different values (equals to 10%, 20% and 30%), and Nano Aluminum with Nano Titanium powder for Aluminum powder, the particle size (d) is less than or equal to 50 nm (d ≤ 50). The weight fraction has different values (equals to 10%, 20% and 30%). Also for Titanium powder, the particle size is less than or equal to 50 nm (d ≤ 50), and the weight fraction is 1% for each different weight fractions of Aluminum powder to epoxy resin. The experimental results obtained from laboratory have been analyzed in order to achieve the best result. It is concluded that Young’s modulus and modulus of rigidity increase when the weight fraction for Nano Aluminum powder and Nano Aluminum with Nano Titanium powder increase.

Nowadays, environmental sustainability is the responsible of engineering community for which the usage of waste or recycling is essential towards ecological sustainability, for which green materials are considered widely in all sectors. Because of the significance of characteristic filler supported composites in the advancement of lightweight materials, this research exploration centers around utilizing biodegradable garbage such as used tea dust powder reduces the impact of environmental pollution. In this study, effect of organic residue, tea dust is effectively recycled/utilized for fabricating polymer composite to find its suitability in engineering applications. Epoxy polymer is considered as matrix material and different volume fractions of used tea dust powders (10, 20, 30, 40, 50, and 60 vol%) are used as reinforcement. Hand-layup approach is adopted for fabricating the polymer composite and the samples are tested for their mechanical properties viz., impact, flexural and tensile strength. Based on the mechanical strength the best combination is found to be 40% vol. in epoxy matrix; higher addition than 40% reduces the strength due to lower bonding between the powders and matrix.

The study is aimed to utilize the silica fume coated plastic waste in the concrete in place of uncoated plastic waste. The main aim of the study is to evaluate the effect on fresh and mechanical properties of concrete after coating the plastic waste with mineral admixture i.e silica fume. The study of utilization of different kinds of plastics forms in concrete has been carried out earlier as well. The major concern is the bonding between concrete mix and the plastic by which the strength could not be attained as desired as per the grade. The present investigation is an endeavor to enhance the bonding characteristics of waste PET fibers with concrete mix by coating them with mineral admixture such as silica fumes by utilizing epoxy resins as an adhesive. The examination was done by utilizing waste PET fibers in aspect ratio AR 25 (50 mm נ2 mm), AR 50 (100 mm נ2 mm) and AR 75(150 mm/2 mm) and consolidate them as bond weight in separate interims of 3%, 6%, 9% and 12%. The modern and mechanical qualities of concrete mix investigated with incorporation of silica fume coated waste PET fibers and ordinary waste PET fibers were contemplated.

This study reports the synthesis of a kind of biomass-based plasticizer: epoxy eleostearic acid catechol ester (EEAE), originating from biomass resources eleostearic acid and catechol by way of esterification and epoxidation. Its effect on the plasticization, mechanical properties and migration resistance of poly(vinyl chloride) (PVC) film was investigated. The results showed that epoxy groups were covalently bonded on the branched chains of EEAE and the epoxy groups and ester groups of EEAE formed hydrogen bonds with the α-hydrogen of PVC, which had a better plasticizing effect on PVC than commercial diisobutyl phthalate. When the mass of EEAE increased from 0.2 to 0.8 g in PVC films, the glass transition temperature (T g) decreased from 86.7 to 54°C and the elongation at break of the PVC films increased from 124.24 ± 6.00 to 321.12 ± 6.13%, while the tensile strength decreased from 40.12 ± 1.23 MPa to 19.67 ± 2.33 MPa, which illustrated that EEAE had an efficient plasticizing effect on PVC. The plasticizer showed marginal resistance to volatilization and solvent extraction. The thermal stability and compatibility of PVC films plasticized with EEAE were also improved.

Spacesuits and spacecraft must endure high velocity impacts from micrometeoroids. This work considers the impact of 100 μm diameter projectiles into composite targets at velocities from 0.5 km/s to 2 km/s. This work begins by presenting an energy-based theoretical model relating depth of penetration (DoP) and impact force to impact velocity, characteristic time, and threshold velocity and force. Next, this work compares numerical simulations of normal impact on composites to the theoretical model. Numerical simulations are conducted with LS-DYNA and the well-known composite model, MAT-162. The numerical models consider unidirectional S2-glass fiber reinforced SC-15 epoxy composite laminates. The numerical model shows good correlation with the theoretical model. The numerical model also investigates lateral impact, parallel to the fiber direction, and oblique impact at angles from 30° to 82.5°. This work decomposes oblique impact into normal and lateral components, and compares them with normal and lateral impact results. The results show good correlation of the normal component of oblique results with the theoretical model. This numerical and theoretical study focuses on DoP, velocity, and penetration resistance force as functions of time. The theoretical model and numerical simulations are used to determine new DoP parameters: characteristic time of depth of penetration and threshold impact velocity. These models are a first step in developing the capability to predict DoP for oblique, microscale, high-speed impact on composite materials.

The amalgamation of metallic alloys and fiber-reinforced composites has helped Fiber Metal Laminates (FMLs) like Carbon fiber reinforced aluminum laminates (CARALL) and Glass laminate aluminum reinforced epoxy (GLARE) overcome the limitations of standalone metals and composites. As a result, they have found increasing applications in the aircraft and defense industries. Moreover, the inhomogeneous nature and poor machinability of the materials make hole drilling a challenging task. Therefore, to enhance drilling performance, the paper reports a systematic analysis on the effect of spindle speed and axial feed on key performance measures, including thrust force, machining temperature, surface roughness, hole size, burr size, and chip morphology. Experimental outcomes indicate a significant reduction in the thrust force while utilizing higher spindle speed (4000 rev/min) and lower axial feed (0.1 mm/rev), while the surface finish improved under high feed conditions (0.4 mm/rev). The analysis revealed that machining temperature increased with the employment of higher spindle speed and lower axial feed. Higher spindle speeds and axial feeds are desirable from the perspective of hole accuracy as they help produce holes within H9 diameter tolerance. Burr size was verified to be larger at the hole exit compared to hole entry, with the size of the burr increasing with an increase in spindle speed and axial feed. The results show that the axial feed was the significant variable affecting chip size followed by spindle speed. Higher axial feed (0.4 mm/rev) and spindle speed (4000 rev/min) helped improve the chip breakability, thus helping in better chip evacuation.

Superhydrophobic coating has been widely studied for its great applicational potential, such as for corrosion protection of magnesium alloys while it has been restrained by expensive materials, sophisticated preparation process and infirm rough structures. In this study, the electrochemical method was adopted by using a two-electrode system for rapid hydrophobic modification to obtain superhydrophobic kaolin. By mixing the modified superhydrophobic kaolin with commercial epoxy resin and polydimethylsiloxane glue, a paint can be formed and easily used on various substrates for preparation of superhydrophobic coating via spraying method. The influence factors on wettability of the modified kaolin and the mixing ratio of each component of the coating were explored. Also, the wettability, durability and anticorrosion of the prepared coating were evaluated comprehensively. The coating was able to maintain superhydrophobic after immersed in HCl solution at pH 1, the NaOH solution at pH 14, and 3.5 wt.% NaCl solution for 16, 21, 30 days, respectively. In addition, the coating exhibited 4A grade adhesion, high hydrophobicity after abraded for 200 cycles on a 600-mesh sandpaper with 100 g weight, and 99.86% anticorrosion efficiency after soaked in 3.5 wt.% NaCl solution for 20 days, demonstrating a good robustness and anti-corrosion property. Furthermore, the coating showed good transparency, flexibility and was easy to make in a large scale by the spraying method, which is of great significance to promote the practical application of superhydrophobic coatings and the anticorrosion Mg alloys.

The paper presents tribological tests of selected materials used as liners in a composite hydraulic cylinder. Three coating materials were used for the analysis: Sika F180 polyurethane, Huntsman Araldite LY1564 with Aradur 3487 amine hardener and Bezlona 1111 Super Metal. In addition, uncoated carbon epoxy laminate (CFRP) samples were used as reference material. The instantaneous course of the friction force, its maximum and average value, were the analysed parameters. Ball-on-disk tests were performed on a specialised tester that allows, among other things, to control the operating conditions (clamping force, operating temperature, speed, friction path) and measurement of the instantaneous value of the friction force. After these tests, the friction paths were observed using a Leica DCM8 contactless profilometer with an EPI 20x lens. The amount of energy dissipated due to friction was also determined. The conducted tests and comparative analyses allowed to conclude that the F180 material is the most desirable in terms of tribological properties.

High-performance ballistic fibers, such as aramid fiber and ultra-high-molecular-weight polyethylene (UHMWPE), are commonly used in anti-ballistic structures due to their low density, high tensile strength and high specific modulus. However, their low modulus in the thickness direction and insufficient shear strength limits their application in certain ballistic structure. In contrast, carbon fiber reinforced epoxy resin matrix composites (CFRP) have the characteristics of high modulus in the thickness direction and high shear resistance. However, carbon fibers are rarely used and applied for protection purposes. A hybridization with aramid fiber reinforced epoxy resin matrix composites (AFRP) and CFRP has the potential to improve the stiffness and the ballistic property of the typical ballistic fiber composites. The hybrid effects on the flexural property and ballistic performance of the hybrid CFRP/AFRP laminates were investigated. Through conducting mechanical property tests and ballistic tests, two sets of reliable simulation parameters for AFRP and CFRP were established using LS-DYNA software, respectively. The experimental results suggested that by increasing the content of CFRP that the flexural properties of hybrid CFRP/AFRP laminates were enhanced. The ballistic tests’ results and the simulation illustrated that the specific energy absorption by the perforation method of CFRP achieved 77.7% of AFRP. When CFRP was on the striking face, the shear resistance of the laminates and the resistance force to the projectiles was promoted at the initial penetration stage. The proportion of fiber tensile failures in the AFRP layers was also enhanced with the addition of CFRP during the penetration process. These improvements resulted in the ballistic performance of hybrid CFRP/AFRP laminates was better than AFRP when the CFRP content was 20 wt% and 30 wt%.

The present study investigates the mechanical and thermal behavior of polyurethane electrostatic powder coating waste reinforced epoxy composites. Different percentages of electrostatic powder coating waste (3, 6, and 9 wt. %) reinforced epoxy composites were manufactured. The mixture of polyurethane powder coating waste and epoxy was mixed with a magnetic stirrer to ensure that the polyurethane powder coating waste was dispersed well in the epoxy, and then the mixture was placed under vacuum and air bubbles were removed. Tensile and three-point tests were performed to determine the changes in the mechanical properties of the materials, and thermogravimetric analysis was conducted to determine the thermal properties. In addition, images were taken with scanning electron microscopy for morphological features. The study revealed that the three-point flexural strength was increased by up to 8% and 15%, respectively, in the samples with 3 wt% and 6 wt% powder coating waste additives. The material's tensile strength decreased by up to 27% with powder coating waste reinforcement. However, the opposite trend was observed in the modulus of elasticity. Additionally, no significant difference was observed in the thermal properties of the materials. Also, from scanning electron microscopy analysis, it was observed that the inclusion of powder coating waste changed the damage mechanism of the material.

The dispersion of nanoparticles plays a key role in enhancing the mechanical performance of polymer nanocomposites. In this work, one hybrid epoxy nanocomposite reinforced by a well dispersed, zinc oxide functionalized, multi-wall carbon nanotube (ZnO-MWCNT) and core-shell rubber (CSR) was prepared, which possesses both high modulus and fracture toughness while maintaining relatively high glass transition temperature (Tg). The improved fracture toughness from 0.82 ​MPa ​m1/2 for neat epoxy to 1.46 ​MPa ​m1/2 for the ternary epoxy nanocomposites is resulted from a series of synergistic toughening mechanisms, including cavitation of CSR-induced matrix shear banding, along with the fracture of MWCNTs and crack deflection. The implication of the present study for the preparation of high-performance polymer nanocomposites is discussed.

Epoxy resin powder coating has been successfully applied on the corrosion protection of magnesium lithium alloys. However, poor wear resistance and microcracks formed during the solidification have limited it extensive application. There are limited approaches to exploit such anti-corrosion and mechanical properties of magnesium lithium alloys. Herein, the epoxy resin powder coating with polydopamine modified molybdenum disulfide (MoS2@PDA-EP powder coating with 0, 0.1, 0.2, 0.5, 1.0 wt.% loading) was well prepared by melt extrusion to investigate its anticorrosion performance and wear resistance. The results revealed that the addition of MoS2@PDA enhanced the adhesion strength between coatings and alloys, wear resistance and corrosion protection of the powder coatings. Among them, the optimum was obtained by 0.2 wt.% MoS2@PDA-EP powder coating which could be attributed to well dispersion and efficient adhesion with coating matrix. To conclude, MoS2@PDA-EP powder coating is meaningfully beneficial for the anticorrosive and wear performance improvement of magnesium lithium alloys.

Epoxy is being extensively used in various engineering and structural applications. Epoxy is non-biodegradable, thus creating ecological problems. Apart from ecological problems, epoxy resin shows poor biofouling prevention in marine, freshwater and offshore environments. In the search for an eco-friendly solution to this problem, epoxy/chitosan/silver nanocomposites were devised. Chitosan was extracted from shrimp shells following deacetylation of chitin, and silver (Ag) nanoparticles synthesized using a chemical reduction process of silver salts. All the composite samples were prepared utilizing the solution casting method. The X-ray diffraction pattern and Fourier transform infrared analysis predict the successful creation of silver nanoparticles and chitosan, respectively. Different mechanical testings elaborate the fact that addition of chitosan into epoxy resin increases hardness, lowering tensile and flexural strength, whereas incorporation of silver nanoparticles reverses those properties, resulting in mechanical properties analogous with neat epoxy resin. Additionally, soil burial biodegradation testing ensured relatively greener characteristics of the final nanocomposites. Herein, the combined effect of chitosan and silver nanoparticles on an epoxy matrix is reported for the first time.

With the rapid development of the electronic industry, the requirements for packaging materials with high thermal conductivity (TC) are getting higher and higher. Epoxy is widely used as package material for electronic package applications. But it's intrinsic TC can't meets the increasing demands. Adding high TC graphene into epoxy matrix is a proper way to reinforce epoxy composites. This review focuses on the filler modification, preparation process and thermal properties of graphene-filled epoxy resin composites. Different ways of covalent and non-covalent modification methods are discussed. The various kinds of graphene coating layer are also summarized. Then we analysis the hybrid filler system in epoxy composite. We hope this review will provide guidance for the development and application of graphene-filled epoxy resin composites.

This article addresses the response of GLAss fiber REinforced aluminum to hypervelocity impacts of micrometeoroid analogs at impact velocities of 7 km/s and beyond. In relation, the damage modes of different GLAss fiber REinforced aluminum configurations have been exemplified. The GLAss fiber REinforced aluminum configurations comprised six to twelve variably thick aluminum layers and up to four plies of glass fiber reinforced epoxy per composite laminate. Hypervelocity impact experiments have been conducted with the help of a two-stage light-gas gun, wherein aluminum- and stainless steel projectiles were launched at velocities up to 7.15 km/s. Visual inspection of the damage area suggested the dissipation of impact energy in elastic-plastic deformation, petalling, delamination, debonding, tensile failure of fibers, and pyrolysis of epoxy. A prevailing damage mode was not apparent albeit. The quasi-isotropic ply orientation of S2-glass/FM94-epoxy laminates promoted the interference of shock- and rarefaction waves and suppressed the damage area of GLAss fiber REinforced aluminum. To discriminate between the impact performance of different GLAss fiber REinforced aluminum configurations, the energy dissipated in different damage modes of GLAss fiber REinforced aluminum has been assessed quantitatively. In terms of normalized energy, the cross-ply GLAss fiber REinforced aluminum dissipated higher energy in petal formation than in other primary damage modes. The normalized petalling energy was found to decline with the increase of impact energy. The outcomes of this study will help to optimize the GLAss fiber REinforced aluminum laminate, which will be employed as a bumper shield to prevent the fatal damage and the unzipping of a spacecraft pressure bulkhead.

My Mechanical Engineering capstone project focused on optimizing the intake system of the University of Virginia’s (UVA) 2023 Formula Society of Automotive Engineers (FSAE) vehicle intended to compete in the Formula SAE competition in Brooklyn, Michigan in May 2023. The intake system includes three main components: Restrictor, Plenum, and Runners. Goals included decreasing the weight of the system, increasing engine horsepower, and improving fuel efficiency. My capstone group went through design constraint screening and scoring over 12 potential intake designs which were completed in the first half of the Fall 2022 semester before focusing on one design. This is UVA’s FSAE team’s third year of competition and improving the functionality of the intake system can help propel the team to a higher overall ranking at the Michigan competition. My capstone group went through extensive research and development of the intake system in the Fall 2022 semester while manufacturing components in the Spring 2023 semester. In the Fall, multiple designs of each component were created on Fusion 360 and went through numerous computation fluids dynamics (CFD) and vibrational analysis simulations to adjust each part’s designs and wall thicknesses. 3D-printers and a computer numerical control (CNC) milling machine were used to manufacture the intake components. This vehicle runs on a 600 cubic centimeter (cc) motorcycle internal combustion engine (ICE) and the UVA team is hoping to transition to an electric Formula SAE car within the next few years. It is important to consider the impact that ICE vehicles and the use of fossil fuels have on the environment. Switching to an electric vehicle will have a positive impact on the environment in addition to giving UVA students an opportunity to enter the workforce with electric vehicle experience. My STS research discusses the need to transition away from a majority fossil fuel source of energy and to nuclear which is much cleaner and sustainable for the environment. Additionally, my research discusses the need for accountability in nuclear disasters. Actor-network-theory (ANT) is used to explore the relationships between the various people and objects involved in producing, regulating, and obtaining nuclear energy. The social construction of technology (SCOT) also explores the technology that safeguards nuclear energy. By exploring the impacts of the Chernobyl nuclear disaster of 1986, the actions of the Soviet Union can be shown to have negatively impacted residents in the area. I expect to discuss the flaws in the reaction to the disaster by the Soviets and how the entire world was needed to help impacted residents. My capstone project and STS research have similar themes of positively impacting the environment and transitioning to more sustainable energy sources: electricity for cars and nuclear for power.

A novel castor-oil-based and phosphorus-containing epoxy resin (flame-retardant epoxy resin (FREP)) and a curing agent – castor oil polybasic acid (AACO) – with high flame retardancy and flexibility were successfully synthesized. The chemical structures of FREP and AACO were characterized by Fourier transform infrared spectrometry (FTIR) and hydrogen-1 (1H) nuclear magnetic resonance spectroscopy. The epoxy resin components were prepared by using bisphenol A epoxy resin (diglycidyl ether of bisphenol A (DGEBA)) with different mass contents of FREP and AACO. DGEBA with 40 wt% FREP (FREP40) possessed a large limiting oxygen index of 29.3%. Cone calorimetry showed that the heat release and smoke production were reduced for both DGEBA with 20 wt% FREP (FREP20) and FREP40 in comparison with those of pure resin (FREP0), indicating that the smoke release and fire hazard of epoxy resin composites with FREP were reduced. Thermogravimetry–infrared spectroscopy suggested that the yields of toxic carbon monoxide (CO), carbon dioxide (CO2) and other pyrolysis products were significantly reduced. FTIR and X-ray photoelectron spectroscopy showed that FREP40 outperformed FREP0 in carbon-forming capacity. The introduction of FREP and AACO effectively increased the elongation at break of pure epoxy resins. FREP and AACO provide a promising strategy for synthesis of epoxy resins with excellent flame retardancy, smoke suppression and flexible performance.

Porous-stabilized rare-earth barium copper oxide (REBCO) tape is an effective structure to solve a trade-off between the current-limiting and recovery performances of the resistive-type superconducting fault current limiters (RSFCLs). In the present study, a current-transfer-type porous-stabilized REBCO tape was proposed to suppress hot spots on the tape, which caused a recovery delay. In this type of REBCO tape, two porous stabilizers with different roles are utilized. The boiling heat transfer performance is improved with one of the porous stabilizers fixed with insulating epoxy on the tape while the current is transferred to the other porous stabilizer to decrease the Joule heating in the hot spot. To design the structure of the current-transfer-type porous-stabilized REBCO tape, the heat transfer performance with a porous medium and insulating epoxy was evaluated. The results indicated that there were suitable specifications for the porous medium and insulating epoxy for high heat transfer performance. The recovery performance of the current-transfer-type porous-stabilized REBCO tape was evaluated with the prototype using the selected porous stabilizer and insulating epoxy. The experimental results showed that the tolerable Joule heating was dramatically improved via current transfer to the porous stabilizer owing to the suppression of the temperature rise of the hot spot. The recovery time was shortened to 0.8 s. The present study showed one way to suppress the hot spots with a simple structure while maintaining the high electrical resistance of the REBCO tape.

A series of experimental tests on reinforced concrete specimens with normal uncoated and epoxy-coated reinforcing bars (ECRBs) was carried out. A comprehensive report of the specimens, from material level to overall performance, is presented in this paper. At the material level, evaluation of the epoxy coating thickness showed that the production quality was not good. Some mechanical properties of bars with a thinner coating were better than those of their uncoated counterparts, while an increase in coating thickness offset the better mechanical properties and decreased the bond strength. Regarding durability, a comparison of the corrosion behaviour of the reinforcing bars and chloride penetration of the concrete cover in unloaded, statically-loaded and fatigue-loaded test specimens showed that higher fatigue loads and longer fatigue loading cycles decreased the corrosion resistance of the bars and increased the chloride penetration. The ultimate loads of the specimens were reduced and comparatively lower values were obtained for beams with bars with thicker coatings. The results of this work highlight the interrelationships among materials performance, durability and ultimate performance to achieve sustainable design for concrete elements with ECRBs in chloride-containing environments.

Biomass-derived dynamic covalent thermoset has been considered as a promising solution to the high dependence on fossil resources and the difficulty in recyclability after curing of conventional bisphenol A epoxy resins. However, the design and preparation of a dynamic covalent biobased epoxy thermoset with both comparable thermal and mechanical performances to bisphenol A epoxy resins and reprocessibility remains a significant challenge. Herein, based on imine chemistry, a novel Schiff base-containing dynamic covalent epoxy thermoset was facilely fabricated from biobased protocatechualdehyde and synthetic siloxane diamine. Due to the more reactive epoxides in the epoxy monomer than in bisphenol A epoxy oligomer, the thermoset exhibited a high cross-linking density, resulting in high thermal stability and glass transition temperature. The rigid aromatic Schiff base moieties endowed the thermoset with excellent mechanical properties: thanks to the plasticization of the flexible siloxane, the thermoset displayed high impact strength. Meanwhile, owing to the high segmental mobility, the fast exchange of imine bonds was guaranteed; and the thermoset was able to be recycled through reprocessing. Taking these features, this work provided great potential for designing and preparing sustainable substitutes for bisphenol A epoxy resins in the high-performance applications.

The woven glass fiber reinforced composites (GFRP) subjected to high-speed impact is investigated to identify the hygrothermal aging effect on the impact resistance. Both the hygrothermal aged and unaged glass/epoxy laminates are subjected to different impact velocities, which is confirmed as a sensitive factor for the failure modes and mechanisms. The results show the hygrothermal aging effect decreases the ballistic limit by 14.9%, but the influence on ballistic performance is limited within the impact velocity closed to the ballistic limit. The failure modes and energy dissipation mechanisms are confirmed to be slightly influenced by the hygrothermal aging effect. The hygrothermal aging effect induced localization of structural deformation and degradation of mechanical properties are the main reasons for the composite undergoing the same failure modes at smaller impact velocities. Based on the energy absorption mechanisms, analytical expressions predict the ballistic limit and energy absorption to reasonable accuracy, the underestimated total energy absorption results in a relatively poor agreement between the measured and predicted energy absorption efficiency.

Interconnected Ni(OH)2 nanoflakes and polyether amine (PEA) were deposited on carbon fiber tows via a facial and effective process of chemical bath deposition and dip coating. Based on this, a win–win benefit of simultaneously improvements in interfacial shear strength (IFSS) of carbon fiber/epoxy composites and the electrochemical activity has been achieved. Compared with CF and CF-Ni(OH)2 composites, the IFSS of CF-Ni(OH)2-PEA/epoxy composite respectively increased 7.9% and 45.4%, which was put down to the covalent bonding of Ni(OH)2-PEA coating with fiber and epoxy matrix, as well as the effective stress transfer by the uniform honeycomb structure of Ni(OH)2. In aqueous KOH electrolyte, the CF-Ni(OH)2-PEA electrode presented the maximum specific capacitance of 689.98F·g−1 at 5 mV·s−1, 572.28F·g−1 at a current density of 0.5 A·g−1 due to the strong adhesion of carbon fiber with Ni(OH)2 by PEA, the reservation of the three-dimensional hollow honeycomb structure of Ni(OH)2 for easy ion-transport and –NH2 functional groups from PEA for providing more active sites. The excellent performance of CF-Ni(OH)2-PEA reinforcement demonstrates its promising potential for application in high performance composites with integrated structure and function, which shows great advantages in various fields of aerospace, energy, electronics, automobile, civil engineering, sports, etc.

In this study, a segmented degradation model was established for the first time to predict and evaluate the dynamic degradation characteristics of carbon fibre-reinforced epoxy composite (CFRC) shells accurately by considering temperature variations during heating, maintenance, and cooling. The model is based on the Reddy's high-order shear deformation theory, complex modulus method, and coefficient fitting approach. First, explicit expressions of material parameters and thermal expansion coefficients (TECs) in different thermal degradation stages were proposed, followed by the derivation of the differential equations to solve the structural dynamic degradation characteristics. Moreover, an identification method for the fitting coefficients of the CFRC material was described, which is based on experimental tests and iterative calculations of elastic moduli, loss factors, and TECs at different degradation time points in different thermal degradation stages. Finally, the natural frequencies, damping ratios, and time-domain responses were measured using a novel testing system for the dynamic degradation of specimens subjected to a pulse excitation load to validate the developed model. Theoretical and experimental results indicate that the natural frequencies decreased as the degradation time increases at the heating-up and temperature maintenance stages, whereas they increased at the cooling stage. However, an uptrend in the damping and response behaviours was observed in the first two stages, whereas a downtrend was recognized at the cooling stage.

Bio-based epoxy thermoset prepared from renewable biomass raw materials can alleviate fossil energy crisis and reduce environmental pollution, which satisfies the needs of sustainable social development. In this study, a bio-based epoxy thermoset precursor (MGOL-EP) was synthesized from a naturally occurring magnolol through a facile and efficient one-step process. And the fully bio-based epoxy thermoset (MGOL-EP-SC) was obtained by self-curing without adding any other hardener. MGOL-EP-SC revealed an extremely high glass-transition temperature (Tg) of 265 °C and char yield of 53.2% (in N2), which were at the highest level among the fully bio-based epoxy thermosets reported so far. In addition, when the MGOL-EP was cured with 4,4′-methylenedianiline (DDM), Tg of the MGOL-EP/DDM was decreased by 61 °C and the other comprehensive performance had also been decreased, which was due to a reduction in biphenyl structure content and cross-linking density by adding the external curing agents. Moreover, the MGOL-EP-SC presented certain killing rate (48.4%) to Staphylococcus aureus. These findings provide a new design strategy for engineering high-performance and functional epoxy thermoset with high biomass content.

Aluminum-based composite abradable seal coatings are pivotal to improving the efficiency of aero engines or gas turbines. However, the adhesive transfer frequently occurs between metallic blade tips and aluminum-based composite coatings, resulting in engine vibration and even jam. Many past studies had tried to solve this problem by reducing coating hardness, improving lubrication, or strengthening blade tips, but all had failed. In this paper, we proposed a novel epoxy-based composite abradable seal coating, eliminating adhesive transfer by changing metal-to-metal scraping pair to metal-to-polymer scraping pair. The coating was developed via a hierarchical structure design. Large spherical pores were uniformly distributed in the continuous epoxy matrix with fine graphite dispersion. By adding 20 vol.% graphite and 50 vol.% hollow microspheres, a self-lubricating epoxy-based coating of 0.26 friction coefficient with thermal conductivity of 0.28 W/(m·K), coating HR15Y hardness at 54.8, and bonding strength at 18.7 MPa can be reached. When the metallic blades scrape the epoxy-based composite coating, no adhesive transfer occurs. Besides, a smooth scraped surface is formed by pseudoplastic deformation. This epoxy-based composite abradable seal coating opens a new way to improve the efficiency and reliable operations of air engine compressors.

In this study, the behavior of two different disks consisting of aramid–epoxy and carbon–epoxy materials under a constant temperature was investigated by using the numerical analysis method. In this study, assuming that the modulus of elasticity does not change with temperature, temperature distributions of 20, 40, 60, 80 and 100°C were applied. It was found that the radial and tangential stress values calculated at high temperatures were higher than those at low temperatures. It was observed that the absolute tangential stresses were much higher than the radial stresses. It is concluded that the elastic stresses occurring in the carbon–epoxy disk are higher than the elastic stresses in the aramid–epoxy disk.

Waterborne epoxy (WEP) resins are of great significance as multifunctional properties recently. Nevertheless, their curing process, which involves the formation of numerous micro-pores via water evaporation, has limited applications in the industrial utilizations. In this work, we have synthesized and enhanced the water-dispersible Zirconium phosphate decorated graphene oxide (ZrP@GO) nanocomposites through a one-step preparation method of graphene oxide (GO) sheets decorated with ZrP nanoparticles, and the as-prepared ZrP@GO nanocomposites were introduced as nanofillers for WEP system in order to enhance its multifunctional properties. The as-prepared GO, ZrP, and ZrP@GO hybrids were scrutinized by XRD, XPS, Raman, TGA, and its morphology study were investigated with the assistance of AFM, TEM, and FESEM. The anticorrosive properties were analyzed using natural salt spray tests (NSS). The ZrP@GO mixed WEP coatings exhibit better protection towards corrosion when compared to WEP/GO and WEP/ZrP coatings. Also, the excellent mechanical and thermal properties were achieved with the incorporation of ZrP@GO hybrids with the WEP system. The better performance of ZrP@GO was achieved through enhanced dispersion, exfoliation, and the outstanding shielding effect of the smectic aligned layers of ZrP@GO hybrids. Besides, a finite element model proposed through this research to predict the tensile behaviors are good in agreement with the measured vales.

Hierarchical layered structures, whether in a compact form like nacre or a porous manner like bone, are well known for their combined features of high stiffness, strength, and lightweight, inspiring many man-made materials and structures for high performance applications. The use of nacre/bone like hierarchical structures in polymer nanocomposites can achieve excellent mechanical and functional properties with high filler volume fractions after carefully aligning functional nanofillers, although the fabrication and processing remain a great challenge. In this work, a bio-inspired lightweight nano-cellular epoxy/graphene-Fe3O4 nanocomposite with high nanofiller loading of 75 wt.% was successfully fabricated by combining features from both nacre and bone structures, via a simple compression molding process together with an eco-friendly supercritical CO2 foaming process to achieve robust mechanical strength and excellent electromagnetic interference (EMI) shielding effectiveness (SE) simultaneously. Highly aligned graphene-Fe3O4 nanoplatelets with well controlled nanoscale porous structures (52.6 nm) enabled both low density (1.26 g/cm3) and high specific EMI SE >5200 dB/cm2/g, as well as preserved tensile strength of 67 MPa. This study provides a sustainable route to fabricate nature mimicked structures with high performance and high flexibility for a wide range of applications, from portable electronics to healthcare devices.

Molecular self-assembly is the most important strategy for the development of chiral aggregates and chiral functional materials. In this study, we rationally designed and synthesized chiral fluorescent heteroclusters that were self-assembled into microscale cubosomes with a three-dimensional (3D) bicontinuous cubic phase nanostructure. The cubosomes exhibited chirality, indicating that chirality is transferred from the molecules to the 3D nanostructure. Therefore, we confirmed the formation of a chiral bicontinuous cubic phase nanostructure for the first time. We also showed that this chirality originates from the continuous change in the saddle-splay distortion of the molecules within the curved bilayer. At the same time, transparent films of chiral composites were prepared by mixing the chiral cubosomes with an epoxy resin and then curing the mixture. Therefore, we demonstrated an effective method for preparing chiral composites.

Using epoxy to repair concrete crack is widely used for restoring concrete structure. Epoxy is used as a base material in composite materials with fillers to improve mechanical and physical properties. The study aims to modify the properties of the epoxy by adding (alumina, silicon carbide, silica fume, pumice) and using This compound is for repairing concrete cracks. Each of the materials (alumina, silicon carbide, silica fume, pumice) were used to harden the epoxy in different proportions (5, 10, 15) by weight. It has particle sizes (45 - 65μm), to prepare composite particles that can be used in construction applications. Further tests are performed to verify whether or not composites are suitable for applications. For the crack repair application, the resulting composites were tested for compression and bending. The resulting compound was applied to treat cracks in previously prepared concrete samples and several tests were performed (compression, bending, and UPV) to determine the effectiveness of this compound in treating cracks in the structural elements.

A graphene/epoxy composite based broadband all-optical tunable fiber microcavity filter is presented. The graphene/epoxy composite based microcavity shows the excellent all-optical controlability. Since the light acts on the graphene/epoxy composite directly, the microcavity has stronger optical Kerr effect and photothermal effect induced by the optical pump. Experimental results show that its wavelength tuning range and tuning step reach 25.54 nm and 832 pm/mW, respectively. It is expected to be applied in the fields of tunable optical filters, optical communication, optical sensors, fiber lasers, and spectrum scanning.

Herein, Pebax functionalized h-BNNSs (P-BNNSs) fabricated by a mechanical exfoliation and in-situ modification process are employed to improve the thermal conductivity and antiwear performance of epoxy resin (EP). Pebax can effectively improve the dispersibility of P-BNNSs, achieving hierarchical assembly of P-BNNSs in EP matrix during EP curing process to form a multinetwork structure only at a low P-BNNS filling contents (≤6 wt%). This multinetwork structure can act as excellent heat conductive pathways to realize simultaneously vertical and horizontal heat diffusion, obtaining quasi-isotropical thermal conductive P-BNNS/EP composites. Fascinatingly, a through-plane thermal conductivity of 3.9 W/(m·K) and an in-plane thermal conductivity of 2.9 W/(m·K) are obtained. More importantly, this special structure can simultaneously improve the antiwear, mechanical and electrically insulating performances of pure EP. The friction coefficients and wear rates of P-BNNS/EP composites (P-BNNS contents ≤ 6 wt%) are dramatically decreased to less than 0.2 and 1 × 10-5 mm3/(N·m), comparing with those of pure EP which are over 0.6 and 2 × 10-5 mm3/(N·m), respectively. The enhanced tensile stress of over 110 MPa and electric volume resistivity of over 1.50 × 1013 Ω·cm are also observed for P-BNNS/EP composite films. These improved properties make the P-BNNS/EP composites very promising as packaging or heat dissipation materials in the high density integration systems and high frequency printed circuit boards.

Novel epoxy resin (E)/CNW nanocomposite coatings were developed with different total contents of rare-earth doped aluminate nanoparticles (REA NPs). The produced epoxy-cellulose nanowhiskers-rare earth doped aluminate nanoparticles (E-CNW-REA) coatings were applied onto mild steel. The epoxy/CNW nanocomposite coatings were characterized by X-ray fluorescence analysis (XRF), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDXA), transmission electron microscope (TEM) and infrared spectra (FT-IR). Both colorimetric properties and transparency of the nanocomposite coatings were proved by exploring UV–Vis absorption spectroscopy and CIE Lab parameters. The hardness and superhydrophobic properties were also explored. The photoluminescent transparent coatings showed an excitation at 365 nm, and a bright green emission wavelength at 517 nm under UV light. The corrosion protection performance of the coated mild steel samples soaked in an aqueous solution of sodium chloride (3.5%) was investigated using electrochemical impedance spectroscopy (EIS). The coatings with CNW were found to have anti-corrosion properties. Moreover, the nanocomposite coating with CNW (1 w%) was monitored to exhibit the most pronounced long-persistent photoluminescence for 60 min in the dark. The photoluminescent coatings exhibited highly durable long-lasting phosphorescence. Thus, the current strategy can be considered as a simple promising technology for industrial production of anti-corrosive, superhydrophobic and long-persistent phosphorescent.

Graphene oxide (GO) can enhance the corrosion resistance of epoxy coating, but there are problems such as poor filler dispersion and mechanical damage that will reduce the coating corrosion resistance. To resolve these problems, here, we used a facile and green liquid-phase synthetic strategy to grow covalent organic framework (COF) on GO sheets with 1,3,5-Triformylphloroglucinol and p-phenylenediamine as monomers for the COF synthesis. The COF could not only improve the compatibility of GO with epoxy coating, but also act as a nanocontainer for loading corrosion inhibitors. Electrochemical impedance spectroscopy showed that the low-frequency impedance of GO/COF-2% coating immersed in 3.5 wt% NaCl solution for 60 days was 8.58 × 108 Ω cm2. This was one order of magnitude higher than that of GO-2%, showing excellent corrosion resistance. Then, corrosion inhibitor of benzotriazole (BTA) was loaded into GO/COF, where the adsorption and release of BTA was controlled by environmental pH values. Results proved that the GO/COF@BTA-2% reinforced epoxy coating had superior corrosion resistance as well as self-healing ability because of the good compatibility, greater crosslinking density and controllable release of BTA.

In this study, a new self-healing strategy that can simultaneously recover the corrosion resistance and the adhesion strength of coatings was introduced. The coating was based on a shape memory epoxy resin containing ethylene vinyl acetate (EVA) microspheres loaded with Ce(NO3)3 inhibitors, and was cured at a relatively high temperature to facilitate the fusion of adjacent microspheres for a strengthened self-healing effect. The electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM) results demonstrated that the shape memory effect of epoxy matrix, the filling of molten EVA microspheres as well as the release of Ce(NO3)3 inhibitors contributed synergistically to suppress the corrosion reaction at the coating damage. After healing, the low frequency impedance modulus of the coatings containing Ce(NO3)3-EVA microspheres was three orders of magnitude higher than that of the blank epoxy coating. The adhesion strength of the coatings containing Ce(NO3)3-EVA microspheres on the metal substrate was also largely repaired thanks to the strong bonding effect of the EVA microspheres.

Graphene-based nanomaterials encapsulated with corrosion inhibitors are promising materials for achieving smart coatings with healable properties. However, the low loading contents of inhibitors (10%–20%) and the cumbersome synthesis processes remain as urgent problems for practical applications. Here, we propose a novel strategy for preparing healable coatings with the enhanced loading of inhibitors enabled by ultra-highly exfoliated graphene and mussel-inspired chemistry. Ultra-highly exfoliated graphene (1355 m2/g) was achieved via a unique one-pot method of H2O2/KOH catalytic exfoliation and etching with residual KOH. Polydopamine (PDA), as a green corrosion inhibitor, effectively promoted the adsorption of benzotriazole (BTA) on graphene via facile co-adsorption. The corrosion perception of this smart coating with the dual healable effect of BTA/PDA was triggered by PDA decomposition from corrosion-induced pH variations. Thus, the coating exhibited an increased impedance modulus (3.31 × 1010 Ω cm2) even after 30 days of immersion (three orders of magnitude higher than that of an epoxy coating), owing to the outstanding barrier effect of the ultra-highly exfoliated graphene and high loading content of inhibitors (30%). This study has a great significance for the design of high-loading smart nanomaterials for sustainable smart systems.

The anisotropic mechanical properties of ultrasound freeze cast epoxy-ceramic composite materials were studied by measuring flexural strength and fracture resistance curves (R-curves) using both unnotched and notched three-point beam bending experiments, respectively, cut in three different orientations relative to the directional freezing axis. Three ultrasound frequencies of 0.699, 1.39 and 2.097 MHz were used in order to introduce different length scales into the microstructure, with 0 MHz used as the control samples. For all cases, the composites showed higher strength and fracture resistance when the crack plane cut across the direction of ice growth (denoted as the YX orientation). The anisotropic properties were more evident for the material produced without ultrasound (0 MHz) where the flexural strength was approximately 160% higher for the YX orientation compared to two orthogonal orientations. Most of the fracture resistance increase was found to occur within a crack extension, Δa, of ∼0.5 mm. Comparing the fracture resistance at Δa = 0.5 mm for the highly anisotropic 0 MHz samples showed that the YX orientation was approximately 86% tougher than the two orthogonal orientations. When the ultrasound operation frequencies of 0.699, 1.39 and 2.097 MHz were applied, the amount of anisotropy in the strength and fracture resistance gradually decreased as the operating frequency increased. The high strength and fracture resistance for the YX orientation was attributed to the alignment of the ceramic particles along the freeze front direction creating a barrier for crack propagation. Ultrasound modifies the material microstructure, introducing relatively dense ceramic layers perpendicular to the freezing front direction that act as an additional, orthogonal barrier to crack propagation. The addition of the denser layers acts to improve the mechanical properties in the weaker orientations and reduce the overall anisotropy.

In order to improve the anticorrosive performance of waterborne epoxy (WEP) coating, small amounts of polyaniline (PANI) were blended under ultrasonic irradiation to obtain PANI/WEP composite coatings with high dispersibility of PANI particles. The PANI/WEP composite coatings were characterized by Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM). Their adhesive force level and hardness grade were tested based on the Chinese National Standard GB/T9286-1998 and GB/T6739-1996, respectively. These results indicated that, compared to the pristine WEP coating, the addition of PANI with suitable content could completely fill the micropores or microcracks and remarkably improve the hardness grade of composite coatings. The electrochemical impedance spectra (EIS) and Tafel polarization curves revealed that the addition of PANI not only could increase the impedance arc, but also could increase the impedance modulus at low frequency. Then, the salt spray tests were employed to observe the anticorrosive performance of PANI/WEP composite coatings. Finally, the enhanced anticorrosive mechanism of WEP coating by the addition of small amounts of PANI was proposed and discussed. The addition of PANI with suitable content could play an important role of physical and chemical barriers to improve the anticorrosive performance of waterborne epoxy coating.

In the recent decade, a strong push toward development of more biobased binders for coating applications as part of the transition toward independence from nonrenewable fossil-based raw materials has been seen. Here we present a biobased epoxy lignin/rapeseed fatty acid derivative (eFA-L), which has been applied in coating systems, leading to coatings with >97% biobased content and Y = 130 MPa. To approach the strength of classical epoxy systems, a series of bimodal systems, containing low molecular weight adducts of biobased diglycidyl furan-2,5-dicarboxylate (DGFDC) and fossil-based diglycidylether bisphenol A (DGEBA) were prepared. In these bimodal systems, it was shown that DGEBA contributes to higher mechanical strength compared to DGFDC at equivalent cross-linking density, which was attributed to increased π–π stacking interactions. The biobased bimodal binder system composed of eFA-L and DGFDC (30 wt %) resulted in a coating with a biobased content of 93 wt %, Y = 440 MPa, and Tg > 50 °C. Better mechanical properties (Y = 700 MPa) were achieved by use of DGEBA (30 wt %), but it results in a significant reduction in biobased content to 62 wt %.

In this work, the hybrid natural fiber composites (NFCs) were prepared using a standard hand lay-up technique from Banana fiber (B), Sisal fiber (S), and sawdust (SD) with different compositions viz. S-I (B 60%–S 20%–SD 20%), S-II (B 80%–S 5%–SD 15%) and, S-III (B 80%–S 15%–SD 5%) bounded with 80% epoxy resin LY556 and hardener LY953 in the 4:1 ratio as per ASTM standards. All the specimens were made with proper composition of 20 wt% of reinforcing materials and 80 wt% of the matrix material. The mechanical (tensile strength, compressive strength, flexural strength, and impact strength) properties and Brinell hardness of prepared specimens were conducted according to ASTM standards. The tensile, compressive, flexural, and impact strength, as well as Brinell hardness of the prepared NFCs, were found to increase with the increase in sawdust content in the epoxy matrix. Further, an improvement in the water absorption property was registered with the increment of sawdust content in the banana-sisal/epoxy composite. The value of dielectric permittivity increased while that of tangent loss decreased with increasing sawdust content. The improved mechanical, dielectric as well as water absorption properties and better Brinell hardness, foreshadow the industrial promises of the present NFCs a better alternative for synthetic fiber-reinforced composite materials.

This study proposes an innovative carbon fibre reinforced polymer composite-geopolymer concrete (CFRP-GPC) system to improve the durability and structural performance of existing deteriorated reinforced concrete (RC) bridges. A rigorous experimental program is designed to investigate the transport mechanism of corrosive agents such as acids and chloride in the constituents via mechanical and microstructural analysis and to develop diffusion models for CFRP-GPC systems considering synergistic effects of temperature and pH fluctuations. Experimental results show that tensile strength of CFRP and epoxy resin reduces by up to 25% and the failure of composite mainly occurs at the fibre-epoxy interface after exposure to acid. The compressive strength of geopolymer concrete decreases by 66% and 61.3% while the mass loss reduces by 5.3% and 3.7% for samples after exposure to the 10% and 32% hydrochloric acid solution, respectively. The diffusion coefficients of the constituent materials vary from 10-8 to 10-6 mm2/s whilst the diffusion rate within the CFRP is the lowest due to the presence of carbon fibres. Furthermore, a computational model is established to evaluate the performance of the proposed hybrid system in improving long term durability performance of a roadway geopolymer concrete bridge in Australia. The numerical results indicate that the proposed CFRP-confined GPC can substantially impede the acid diffusion into the bridge column, and reduce the level of diffusion and thereby improve the service-life. Parametric study shows that the diffusion rate in CFRP-GPC columns increases up to 58% and 394% for epoxy and CFRP when temperature elevates from 23 °C to 80 °C. In addition, elevation in the exposure temperature from 23 °C to 80 °C increases the mass loss to 22% and 25% under pH = 1 and 7. The findings of this research provide a framework for durability design of hybrid CFRP-GPC systems.

Surface initiated electro-polymerization of acrylamide on carbon fiber with methodically varied amounts of acrylamide monomer and N,N′-methylene bis-acrylamide crosslinker is explored in this study. The effect of the polymer coating on tensile strength, Young's modulus, and interfacial properties of carbon fibre in an epoxy resin was determined. A significant improvement in tensile strength, tensile modulus, and interfacial shear strength (IFSS) across all modified samples was observed, with the most notable improvements to tensile strength, tensile modulus and IFSS being 38%, 15% and 192.5%, respectively. This covalently bound polymer coating provides the best kind of solution for the two most crucial limitations of carbon fibre, with the minimum amount of effort, time, and cost.

Natural fiber reinforced polymer composites are attracting many scientist and researcher across the world to develop low cost, biodegradable and environmentally friendly materials. Therefore, for the present study a cantilever beam prepared from natural fiber reinforced polymer composite has been selected for the finite element analysis. We have considered nettle/polyester and chicken feather/epoxy composites material for the development of a cantilever beam to analyze the vibration behavior using ANSYS. The modal analysis was carried out to predict the natural frequencies and mode shapes of the beam structure. During the study natural frequencies and mode shapes of the nettle/polyester and chicken feather/epoxy beam structures were compared with each other. It is found from this analytical study that the natural frequencies of nettle/polyester cantilever were more than chicken feather/epoxy. The natural frequency of nettle/polyester and chicken feather/epoxy cantilever beam varies from 30.196 Hz to 1031.7 Hz and 16.371 Hz to 559.84 Hz respectively. These result obtained through modal analysis will be beneficial for engineers and scientists to find safe working condition while developing mechanical and structural member with these composite materials.

Polymer matrix composites with different fibre glass reinforcements like wool, woven ring and mesh has been prepared through hand layup method for the experimental investigation on compression strength and weight evaluation. EPOXY/PVC blend has been used as matrix material with different weight percentages of PVC such as 5%, 15% and 25%. The prepared specimen has been subjected to heat treatment in a oven for different timing such as 15, 30 and 45 min. The present study considers the percentage of PVC, fibre glass type and heating time as input factors to observe their effect over weight and compression strength of the specimen through Taguchi’s L27 Orthogonal array. The statistical analysis of experimental results through signal to noise ratio method and ANOVA reveals that the type of fibre used for making the specimen has more influence over both the output parameters. The heat treatment provided to the specimen and the percentage of PVC has no significant effect and the residual error in analysis is around 10%.The investigation carried out reveals that 5% PVC composition with woven rings reinforcement material has shown the maximum compression strength and highest specimen weight and the changes in matrix material combinations with different PVC compositions, fiber glass with increased or decreased thickness may be considered as the future directions of the current study.

Thermoplastic blend effect in modifying DGEBA matrix is found to be effective in improving the mechanical as well as the micro-crack resistance properties of the prepared composites. The thermoplastic content is selected to be 1.5 wt% of DGEBA resin for modification via melt mixing. The modified epoxy along with 2x2 twill weave carbon fiber was used to develop specimens for testing via vacuum assisted resin transfer molding (VARTM). The blend effect of poly(acrylonitrile-butadienestyrene) (ABS) in polycarbonate (PC) shows enhancement in impact resistance (maximum 20% increase) of DGEBA based carbon fiber (CF) composites compared to the unmodified system under room conditions. The SEM images reveal high levels of heterogeneity for the modified system with lesser levels of deeper cracks and delamination, making it more stable under room conditions. The laser scanning optical profilometry reveals minimal micro-cracks formed on the modified system under 150x magnification, making it more effective for aerospace applications.