Fiberglass Recovered from Epoxy Composite Material Using Solvolysis in Pyridine

In this paper work the dynamic structural Finite Element Analysis of internal door panel of a vehicle by considering bamboo fiber reinforced epoxy composite (BFREC) materials was conducted. The objective of the paper is to develop a suitable model of internal door panel for Toyota DX car, to conduct a transient dynamic structural analysis (stress and displacement analysis) of internal door panel by finite element method, to compare the performance of BFREC material with previously recommended materials of internal door panel. The door panel of Toyota Corolla DX model vehicle was used to develop the geometric model of the internal door panel by CATIA V5 R20 modeling software. This 3-D geometric model was imported to using ANSYS Workbench 15.0. The transient dynamic structural FEA was done after assigning loading and boundary conditions. The applied load considered for this analysis is the self-inertial weight of the panel due to the acceleration field produced while the door is closing. The equivalent stress and the displacement are noted and investigated to compare with the literatures revised. The result shows that, bamboo fiber reinforced epoxy composite panel has the smallest mass and equivalent stress values, as compared with the lignocellulosic composite and polypropylene one. Based on these realities, it is recommended that bamboo fiber reinforced with epoxy composite materials are suitable for internal structural automotive panel applications.

Carbon fiber epoxy resin composite and polyimide material are likely to be applied to pulley-guideway system of the new satellite antenna. Their tribological properties have effects on the motion characteristics of the pulley-guideway system. To master the tribological properties of carbon fiber epoxy resin composite and polyimide material, this paper carries out tests of tribological properties and wear behavior of carbon fiber epoxy resin composite and polyimide material at 130°C and 30°C. Carbon fiber epoxy resin composite is used as the grinding specimen and polyimide material is used as the counter-grinding specimen. Tribological properties of this material pairs is studied under diverse linear velocity and external loads. The results show that friction coefficient of this material pairs is stable under different conditions, especially at 30°C. Meanwhile, wear behavior of this material pairs is mainly affected by ploughing of surface roughness at low temperature, while by surface micro-spalling at high temperature.

Epoxy composite materials (ECMs) combine unique adhesive strength, heat resistance, and wear and corrosion resistance and are the basis for producing body components, sliding bearings, and protective coatings. To obtain epoxy composite materials, ED-20 epoxy resin, polyethylene polyamine as a curing agent, modifiers, and superfine reinforcements are used. Methods to control the structure and properties of ECMs with different reinforcement contents are justified, and structurization mechanisms depending on the nature and morphology of the ingredients and their ratios in the system are established. The structure and properties of epoxy composite materials depending on the reinforcement content are analyzed. Predominant factors that influence the properties of low-, medium-, and high-reinforced epoxy composites are identified. Additional ultrasonic treatment of composites in the formation stage is shown to be effective and improve the strength of the system owing to its higher homogeneity per microvolume, better wetting, and more active interaction at the interface.

This study explores the transformative effects of treating durian peel fibers with Ca(OH)2 solution and their subsequent application as a reinforcing agent in epoxy composite materials. Morphological and structural analyses reveal a notable improvement in compatibility and adhesion between treated fibers and epoxy resin, particularly at a 5 % Ca(OH)2 concentration. Durian fruit peel, after being treated with clear lime water (Ca(OH)2), is used to reinforce the epoxy composite material at the ratio of epoxy/durian fiber peel = 70/30. The results were established when durian peel fibers treated with 5 % lime water solution had the best mechanical properties (tensile strength: 65.68 MPa, flexural strength: 92.11MPa, compressive strength: 147.38 MPa, Izod impact strength: 9.07 kJ/m2). In terms of fire retardancy, the best results were also obtained when reinforcing durian peel fibers treated with 5 % concentration of lime solution in Ca(OH)2, specifically: Minimum oxygen index: LOI = 21.9 %, Burning speed according to UL 94: 20.66 mm/min. The structural morphology of the epoxy/durian peel fiber composite was evaluated using SEM. The results demonstrated good compatibility, with no evidence of layer exfoliation or phase separation at the epoxy resin-durian peel fiber interface when subjected to external forces. The results of the project indicate that epoxy composites reinforced with durian peel fibers hold great promise as a green, environmentally friendly material. By utilizing waste from the food industry, these composites offer potential applications across various fields, including the automotive, transportation, and construction industries. HIGHLIGHTS Durian Peel Fiber Treatment: Durian peel fibers treated with 5 % Ca(OH)₂ solution for better adhesion to epoxy. Composite Reinforcement: Epoxy composite reinforced with 30 % durian peel fiber (epoxy/durian fiber = 70/30). Mechanical Properties: Best results with 5 % Ca(OH)₂-treated fibers (tensile strength: 65.68 MPa, flexural strength: 92.11 MPa, compressive strength: 147.38 MPa, impact strength: 9.07 kJ/m²). Fire Retardancy: Improved fire resistance (LOI = 21.9 %, burning speed: 20.66 mm.min-1). Applications: Promising for use in automotive, transportation, and construction industries. GRAPHICAL ABSTRACT

In this study, we conducted the hygrothermal aging of an epoxy composite insulation material at 95% relative humidity (RH) and temperatures of 95 °C, 85 °C, and 75 °C. We measured electrical properties, including volume resistivity, electrical permittivity, dielectric loss, and breakdown strength. It was found to be impossible to estimate a lifetime based on the IEC 60216 standard, because it uses breakdown strength as its criterion even though breakdown strength hardly changes in response to hygrothermal aging. In analyzing variations in dielectric loss with aging time, we found that significant increases in dielectric loss correlated well with lifetime prediction based on the mechanical strength of the material, as described in the IEC 60216 standard. Accordingly, we propose an alternative lifetime prediction criterion by which a material is deemed to reach its end of life when its dielectric loss reaches 3 and 6-8 times the unaged value at 50 Hz and low frequencies, respectively.

Dynamics of graphite/epoxy composite under delamination fracture and environmental effects

Composite materials have a wide range of applications including as an automotive components. In certain applications it is exposed to various heat conditions and might affect its mechanical properties. It is important to be able to predict the behavior of the composites under different temperature settings in order to prevent failure. The GIIC properties of composite epoxy laminate with silk fibre at various temperatures have yet to be investigated by any researcher. This study was carried out to analyse the Mode II interlaminar fracture properties, GIIC of the silk fibre / epoxy composite materials when treated with silane coupling agents at different test temperatures. This property is important since it provides the measure of the material’s resistance to delamination crack propagation. Composite specimens were produced using compression moulding technique with sixteen layers of silk fabric. The matrix is an epoxy D.E.R 331 and Hardener Joint mine 905-3S. The weight ratio of mixing epoxy and hardener is 2:1. Six sets of sample were prepared using silk fibre which has undergone surface treatment for 24 hour using silane coupling agent surface treatment solution. Specimens were tested by Instron Universal Testing Machine using a three-point bending based on an end notched flexural (ENF) method. The tests were carried out at six different temperatures which are at 20 oC, 23 oC, 26 oC, 38 oC, 50 oC and 75 oC. The temperature of the specimens during testing was monitored using a thermal imager in order determine the exact test temperature. It was found that as the temperatures increases, the mode II fracture toughness decreases by up to 71%. The length of crack propagation shows that higher temperature leads to longer crack length. This could be due to the residual tension between the fibre and matrix as they have different thermal coefficient of expansion.

Mixing operations play a vital role in various industrial processes, with the structural integrity of mixer shafts being crucial for optimal performance and reliability. This study investigates the design, modeling, and Finite Element Analysis (FEA) of a paddle mixer shaft, comparing two configurations—one with stiffeners and one without. The shaft assembly, including components such as the pipe, end shafts, stiffeners, and paddles, was modeled using Pro-E software, while ANSYS 13.0 was used for FEA to assess stress distribution, deformation, and structural performance under applied loading conditions. A static analysis was conducted, considering self-weight, gravity, and applied pressure of 0.77 MPa, with uniform boundary conditions applied to both configurations. The results indicate that the stiffened paddle shaft exhibited lower maximum stress (105.26 MPa) and deformation (1.5 mm) compared to the shaft without stiffeners (173.05 MPa stress and 2.1 mm deformation). Theoretical calculations confirmed that stress values remained within permissible limits for Stainless Steel (SS), making the stiffened shaft the preferred design. Additionally, the study explores potential weight reduction by replacing SS with carbon/ epoxy composite materials, demonstrating significant weight savings while maintaining structural integrity. Manufacturing processes, material specifications, and experimental validation through hydrostatic and load trials confirmed the reliability of the selected design. The trials showed an 8% deviation between experimental and simulated deformation, reinforcing the accuracy of the FEA approach. This research underscores the importance of structural reinforcement in paddle mixer shafts and provides valuable insights into design optimization, material selection, and performance validation. Future studies could explore further weight reduction using advanced composites, ensuring both durability and cost-effectiveness. Major Findings: The study revealed that the stiffened paddle shaft exhibited superior structural performance, with lower maximum stress (105.26 MPa) and deformation (1.5 mm) compared to the unstiffened shaft (173.05 MPa stress and 2.1 mm deformation), highlighting the effectiveness of stiffeners in enhancing structural integrity. Experimental validation through a hydrostatic test at 7.7×10⁻² MPa showed an 8% deviation between Finite Element Analysis (FEA) predictions and experimental results, confirming the accuracy of the simulation approach. Additionally, the study explored the potential of replacing stainless steel with carbon/epoxy composites, demonstrating significant weight reduction while maintaining mechanical strength and durability, offering insights into future lightweight design optimizations.

Epoxy composite materials with special properties

Experiments were conducted to determine the effects of damage growth caused by humidity cycling between 95% RH and 0% RH at 40°C on AS4/3502 graphite/ epoxy composite material. Tests were performed to measure tensile and compressive moduli, Poisson's ratios, and ultimate strengths. Fracture behavior was determined from double cantilever beam tests in which energy release rates were measured. In virtually all cases it was found that the cycling conditions utilized in this work did not lead to any sig nificant changes in moduli, Poisson's ratio, ultimate strength, or energy release rates de spite the fact that micro-level damage was known to be present.

Nanomaterials are integrated within consumer products to enhance specific properties of interest. Their release throughout the lifecycle of nano-enabled products raises concerns; specifically, mechanical strains can lead to the generation of fragmented materials containing nanomaterials. We investigated the potential release of single-walled carbon nanotubes (SWCNTs-brand TUBALL™) from epoxy composite materials. A pin-on-disk-type tribometer was used for the accelerated mechanical aging of the nanocomposites. A pristine nanocomposite material, abraded material and debris obtained from the abrasion in the tribometer were analyzed by Raman spectroscopy. The airborne-produced particles were captured using particle collectors. Stat Peel's Identifier C2 system was used to monitor the SWCNT content of respirable particles produced during the abrasion test. The SWCNT amounts found were below the LoQ. The Raman spectra conducted on the Stat Peel filters helped identify the presence of free SWCNTs released from the epoxy matrix, although they were notably scarce. Raman spectroscopy has been proved to be a crucial technique for the identification, characterization and assessment of structural changes and degradation in SWCNTs that occurred during the abrasion experiments.

The construction of steel deck pavements is still considered difficult worldwide, and interfacial bonding is a major factor influencing this construction. With the recent developments in the field of pavement materials, high-performance cement-based concrete is used to construct steel bridge deck pavements. However, ensuring adequate interface-bonding strength remains particularly complex and difficult. In this study, with the aim of striking the right balance between rigidity and flexibility, an interface-bonding material was formed using modified epoxy resin, cement, and rubber powder. Polymer lattice porous concrete was used as the paving material, and the interface-bonding effect was studied experimentally by employing three methods using the material: pull-off, dual-interface shear, and flexural tensile tests. The results showed that (1) the interface pull-off strength was higher than 4 MPa, that is, higher than twice that of epoxy asphalt pavements used currently on steel bridge decks, and the failure surface was located on the pavement material rather than on the bonding interface; (2) the interface flexural strength and tensile strength were significantly higher than those of epoxy asphalt at room temperature and those of the ordinary epoxy resin; (3) the dual-interface shear strength was nearly four times higher than that of epoxy asphalt. Therefore, the modified epoxy resin composite interface-bonding material suggested in this study is an excellent bonding material that can serve as a reference for interface-bonding of steel bridge deck pavements.

Synthesis and characterization of epoxy and natural fiber composite material

The aim of this work is to define the cutting conditions that allow the dry drilling of carbon fiber reinforced epoxy (CFRE) composite materials taking into consideration the quality of the drilled holes (the exit delamination factor and the cylindricity error) and the optimum combination of drilling parameters. A further aim is to use grey relational analysis to improve the quality of the drilled holes. The machining parameters were measured according to 33 full factorial parameter designs (27 experiments with independent process variables). The experiments were carried out under various cutting parameters with different spindle speeds and feed rates. Drilling tests were done using WC carbide, high-speed steel (HSS), and TiN-coated carbide drills. The experiment design was accomplished by application of the statistical analysis of variance (ANOVA). Results show that the thrust force is mainly influenced by the tool materials and the feed rate, which has a strong influence on the exit delamination factor. On the other hand, the spindle speed particularly affects the cylindricity error of the holes. Correlations were established between spindle speed/feed rate and the various machining parameters so as to optimize cutting conditions. These correlations were found by quadratic regression using response surface methodology (RSM). Finally, tests were carried out to check the concordance of experimental results.

In this work, silicone polymer (PSOL)/glass fiber (GF)/epoxy (EP) composites were prepared by employing PSOL as interfacial modifier into GF/EP composites. The mechanical and dynamic mechanical properties of the composites were investigated to determine the optimal PSOL content. The effect of PSOL on the wettability of EP on GF was investigated. The micromorphology of the GF/EP composites was also examined by scanning electron microscope. The results demonstrate that the interfacial bonding between GF and epoxy resin was improved significantly by the addition of PSOL. Specifically, the interlaminar shear strength, tensile strength, elongation at break, and blending strength of the PSOL/GF/EP composites increased by 9.28%, 13.61%, 12.66%, and 19.22%, respectively. Moreover, the original thermal stability of the composites was improved by the incorporation of PSOL. This study highlights the effectiveness of PSOL as an interfacial modifier, enhancing the overall performance of GF/EP composites while improving their thermal stability.Highlights Silicone polymer (PSOL)/glass fiber (GF)/epoxy (EP) composite material is made of glass fiber and epoxy resin by hand paste molding. Silicon polymers as interface modifiers can improve the interface between glass fiber and epoxy resin. PSOL/GF/EP composites have good mechanical properties. The glass transition temperature of GF/EP composites was increased by silicon polymer.