Epoxy Resin Research Articles

Life cycle assessment of glass fibre versus flax fibre reinforced composite ship hulls

A comparative Life Cycle Assessment (LCA) was conducted between a recreational ship hull made of flax fibre-reinforced bio-based epoxy resin and a traditional ship hull made of glass fibre-reinforced polyester. Since small fibreglass boats pose an environmental problem after the end of life (EoL), the primary aim of this study was to evaluate the sustainability of the biocomposite material and identify recommendations for the future eco-design of recreational boats. The LCA study was developed according to the ISO 14,040 (ISO 14040, 2006), 14,044 (ISO 14044, 2006) methodology and the OpenLCA 2.0.4 software with the Ecoinvent v.3.9.1 database. Compared to the traditional one, the LCA of the biocomposite ship hull showed positive environmental impacts for all indicators except Terrestrial Ecotoxicity (TETP), which increased by 357% due to the use of fertilisers in flax production. Remarkably, the Global Warning Potential (GWP) decreased by 14%, the Human Toxicity Potential (HTP) diminished by 13%, and the Abiotic Depletion Potential (ADP) related to material resources was reduced by 75%. The sensitivity analysis shows that electricity consumption is the primary environmental impact driver for the FFRB ship hull. Thus, selecting renewable energy sources, such as solar or wind power, can significantly enhance sustainability. It is important to note that these impacts are influenced by the system and boundary conditions considered in the study. It was suggested that the local production of flax fibre and the use of recyclable bio-resin could improve the eco-design of the ship hull.

Effect of ammonium polyphosphate and benzoxazine synergistic modification on the flame retardancy of epoxy resin

The development of flame-retardant resin with low viscosity and minimal curing shrinkage for the resin transfer molding (RTM) process in aviation is not yet fully mature. Thus, ammonium polyphosphate (APP) and benzoxazine (BOZ) resin were used for the synergistic modification of epoxy to enhance flame retardancy and minimize curing shrinkage in this work. The curing reaction characteristics, rheological properties, flame-retardant performance, and mechanical properties of the modified resin were investigated. The results show that neither APP nor BOZ can simultaneously improve the flame retardancy and mechanical properties of the resin, respectively. However, when 10 wt% APP and 5 wt% BOZ are employed together for synergistic modification, the modified resin (entitled 10A5B) demonstrates an optimally balanced low viscosity and minimal curing shrinkage. Thanks to the combination of the acid source formed by APP, the carbon source formed by the reaction of BOZ with EP, and the non-flammable gases, 10A5B achieves the highest limited oxygen index of 31.3% and the lowest peak heat release rate, total heat release, peak smoke release rate, and total smoke release among the modified resins. The synergistic effect of a stable, continuous, thick, and expanded char layer, along with the dilution of non-combustible gases, significantly contributes to the excellent flame retardancy of 10A5B. Moreover, its tensile strength and impact strength are enhanced by 8.2% and 3.8%, respectively, while the curing shrinkage is reduced by 13% compared to the resin modified with the same mass fraction of APP alone.

Tailoring Epoxy Network Architecture and Stiffness-Toughness Balance Using Competitive Short- and Long-Chain Curing Agents: A Multiscale Simulation Study

Designing high-performance crosslinked polymers requires overcoming the inherent stiffness–toughness trade-off through precise control of the network topology. Using epoxy resin as a model system, we establish a multiscale simulation framework to investigate curing reaction kinetics, network evolution, and structure–property relationships. By employing m-phenylenediamine (mPDA) and 1,3-bis(3-aminophenoxy)benzene (DABPB) as competing short- and long-chain curing agents, we demonstrate how network architecture dictates mechanical performance. Simulations reveal that mPDA produces a dense, heterogeneous network with enhanced stiffness, whereas DABPB forms a more uniform structure with greater chain mobility, leading to improved toughness. Through stoichiometric tuning, we achieve fine control over crosslink density and mechanical properties. Furthermore, we decouple cavity formation mechanisms into pendant chain slippage and bond rupture, offering molecular-level insights for the rational design of epoxy resins with programmable mechanical behavior.

UHMWPE composites: Effect of flame retardant tannic acid as coating agent and hardener for epoxy resin systems

AbstractThis study investigates the dual functionality of Tannic Acid (TA), a bio‐derived polyphenol, as a surface modifier for ultra‐high molecular weight polyethylene (UHMWPE) fibers and as a hardener for diglycidyl ether of bisphenol A (DGEBA) epoxy resin, aimed at enhancing composite laminate performance and sustainability. The surface characteristics of UHMWPE fibers were investigated by Fourier transform infrared spectroscopy and scanning electron microscopy. The TA‐modified fibers exhibited functional groups that enhanced their polarity and improved their compatibility with the epoxy matrix. Furthermore, thermogravimetric analysis revealed an increase in thermal degradation onset from 336°C to 357°C after TA treatment. The hand lay‐up method was used to manufacture composite UHMWPE laminates impregnated with TA‐hardened resins at different TA concentrations. Cone calorimetry results revealed improved fire resistance for TA‐loaded composites, with a 44% reduction in peak heat release rate (PHRR) respect to the control sample, as well as a better fire performance index. Composite laminates manufactured with TA‐modified fibers and TA‐hardened resin demonstrated up to 45% improvement in tensile strength.Highlights Tannic acid (TA) proves to be a sustainable alternative to petroleum‐based hardeners. TA enhances UHMWPE fibers' thermal stability and adhesion to epoxy. TA‐modified fibers show an increase in thermal degradation onset. TA‐hardening of epoxy improves fire resistance, reducing PHRR by 44%. Composite laminates with TA show a 45% increase in tensile strength.

Adhesive system containing Bioglass 45S5 particles in teeth affected by molar-incisor hypomineralization and quality of life impact: study protocol for a randomized clinical trial

BackgroundMolar-incisor hypomineralization (MIH) is a systemic condition characterized by a qualitative defect in the dental enamel. It primarily affects the first permanent molars and is often associated with the permanent incisors. Resin restorations in MIH-affected teeth consistently show worse results than those in normal teeth because of the ultrastructure of hypomineralized enamel, which compromises adhesion. The incorporation of bioactive particles into adhesives is a promising option for inducing remineralization. This study protocol describes a randomized clinical trial evaluating restorative treatment using an adhesive system containing 45S5 bioactive glass for MIH-affected teeth.MethodsRestorations will be performed on the upper or lower first permanent molars in children with MIH aged 6–12 years. The inclusion criteria will include MIH teeth with post-eruptive enamel fractures that compromise the middle third of the dentin, with at least two surfaces of hypomineralized enamel near the cavity, without caries, pulpal, or periradicular involvement. Before treatment, children will complete the Child Perceptions Questionnaire 8–10 and 11–14 (CPQ8–10 and CPQ11–14). The teeth will be divided into two groups: a control group (commercial self-etching adhesive system: Clearfil SE Bond (CF) Primer + Bond) and an experimental group (CF Primer + experimental Bond using 10% 45S5 bioglass [Bond 45S5 10%]). Restorations will be made using composite resin, and quality will be assessed using digital radiographs (interproximal and periapical), intraoral photographs, and epoxy resin replicas. Clinical evaluation of the restorations will be performed immediately following the procedure (baseline) and after 1, 3, 6, and 12 months using the World Dental Federation (FDI) criteria. The impact of the treatment on the quality of life will be assessed after 3, 6, and 12 months through the re-administration of CPQ8–10 and CPQ11–14.Discussion45S5 bioactive glass is capable of enhancing the effect of materials on bone and dental structures, promoting remineralization. The results of this study may aid in the clinical management of patients with MIH, given the challenges of treating sensitive and compromised teeth and the difficulty in achieving long-term restorative success while addressing the individual patient needs.Trial registrationRebec, U1111-1259-1738. Registered on January 10, 2021.

Application of Bio-Based Epoxy Resin Synthesized from Eugenol in Composites Reinforced with Flax, Nettle, and Basalt Fabrics

ABSTRACT The main aim of the study was to evaluate the use of bio-based epoxy resin obtained from eugenol derivatives as a matrix in reinforced composites with flax, nettle and basalt fabrics. Triethylenetetramine (TETA) and isophoronediamine (IDA) were used as curing agents. For the bio-based epoxy monomer, the dynamic viscosity was determined at different temperatures. Fourier-Transform Infrared (FTIR) confirmed the chemical structure of cured composites. The morphology of the composites was assessed by scanning electron microscopy (SEM). The differential scanning calorimetry (DSC) method was used to evaluate the glass transition temperature of composites. Thermal stability was measured by thermogravimetric analysis (TGA) connection with an FTIR spectrometer. Studies confirmed that the eugenol-based resin can be used for the impregnation of natural fiber and the preparation of composite materials. The composites were characterized by multi-stage thermal decomposition confirmed by TGA analysis and low degradation rate determined from DTG curves. The thermal stability of the tested composites with flax and nettle fabrics was on average 235°C, while with basalt fabric it was about 270°C. Composites cured with TETA showed a glass transition temperature Tgof 47.0°C on average compared to composites cured with IDA that showed a Tg of 54.0°C.

The Development of Porosity-Enhanced Synthetic Coal Plugs for Simulating Deep Coalbed Methane Reservoirs: A Novel Laboratory Approach

Deep coal seams in the Junggar Basin, China, have demonstrated high gas yields due to enhanced pore structures resulting from hydraulic fracturing. However, raw coal samples inadequately represent these stimulated reservoirs, and acquiring fractured core samples post-stimulation is impractical. To address this, a novel and operable laboratory method has been developed to fabricate porosity-enhanced synthetic coal plugs that better simulate deep coalbed methane reservoirs. The fabrication process involves crushing lignite and separating it into three particle size fractions (<0.25 mm, 0.25–1 mm, and 1–2 mm), followed by mixing with a resin-based binder system (F51 phenolic epoxy resin, 650 polyamide, and tetrahydrofuran). These mixtures are molded into cylindrical plugs (⌀50 mm × 100 mm) and cured. This approach enables tailored control over pore development during briquette formation. Porosity and pore structure were comprehensively assessed using helium porosimetry, mercury intrusion porosimetry (MIP), and micro-computed tomography (micro-CT). MIP and micro-CT confirmed that the synthetic plugs exhibit significantly enhanced porosity compared to raw lignite, with pore sizes and volumes falling within the macropore range. Specifically, porosity reached up to 27.84%, averaging 20.73% and surpassing the typical range for conventional coal briquettes (1.89–18.96%). Additionally, the resin content was found to strongly influence porosity, with optimal levels between 6% and 10% by weight. Visualization improvements in micro-CT imaging were achieved through iodine addition, allowing for more accurate porosity estimations. This method offers a cost-effective and repeatable strategy for creating coal analogs with tunable porosity, providing valuable physical models for investigating flow behaviors in stimulated coal reservoirs.

Performance of Carbon Fiber-Reinforced Date Palm Midrib Composites

This paper evaluates the performance of composites made from date palm (Phoenix dactylifera L.) midribs reinforced with carbon fiber. Two types of adhesives—unsaturated polyester and epoxy resin—were used as binder for the experimental panels. The physical properties and mechanical strength of the composites, as a function of fiber types, lamination configuration, as well as adhesive types, were determined. The density levels of the panels made using epoxy and unsaturated polyester resin were found to be 1103 kg/m3 and 1133 kg/m3, respectively. Panels made using polyester adhesive had 6.05% and 3.98% for water absorption and thickness swelling values, respectively. Corresponding values of 3.09% and 6.35% were found for the panels made using epoxy resin. Mechanical properties of the samples revealed that carbon fiber-reinforced epoxy hybrids offer superior mechanical performance, whereas polyester-based hybrids may be more suitable for impact-resistant applications. Stereo-microscopy and vertical density profile (VDP) analysis of the panels resulted in variations in layer adhesion and density distribution. Based on the findings in this work, carbon fiber-reinforced epoxy-bonded hybrid panels exhibited superior mechanical properties, while those panels made using polyester-based binder would be more suitable where impact resistance is desired. The combination of date palm fibers and carbon fiber presents significant potential for sustainable applications, offering a balance of strength and durability.

Advances in Toughening Modification Methods for Epoxy Resins: A Comprehensive Review

This work provides a comprehensive review of the recent advancements in the toughening modification methods for epoxy resins. The study explores a variety of approaches, including the incorporation of liquid rubbers, core–shell rubber particles, thermoplastic resins, hyperbranched polymers, and the nanoparticle toughening method, each of which contributes to improving the mechanical properties and fracture toughness of epoxy resins. Special attention is given to the mechanisms underlying these toughening methods, such as reaction-induced phase separation, crack pinning, and energy dissipation through particle deformation. The paper also examines the synergistic effects achieved by combining different toughening agents, such as phenoxy thermoplastic rubber and core–shell rubber particles, which significantly enhance the critical fracture energy and impact strength of epoxy composites. Additionally, the challenges associated with each method, such as the potential reduction in mechanical properties and the influence of phase separation on material performance, are discussed. Through a detailed analysis of experimental studies, this paper highlights the effectiveness of various toughening strategies and suggests future research directions aimed at further optimizing epoxy resin toughening techniques for diverse industrial applications. Emerging computational modeling and machine learning applications in epoxy resin development are also systematically reviewed to highlight their potential in advancing predictive design frameworks.

Preparation and Properties Investigation of Polyphenylene Oxide Modified Epoxy Resin Composites for High‐Frequency Copper Clad Laminates

ABSTRACTAs electronic technology swiftly progresses, conventional epoxy resins can no longer fully meet the demands of copper‐clad laminates (CCLs). To develop an epoxy resin exhibiting superior thermal performance, low dielectric properties, and reduced moisture absorption, low‐molecular‐weight TMBPA‐MPPO‐2OH was successfully synthesized using TMBPA and DMP as comonomers. The molecular structure of TMBPA‐MPPO‐2OH was comprehensively characterized by FT‐IR and 1H NMR spectroscopy. Subsequently, the synthesized monomer was employed to modify epoxy resin E51 in combination with 4,4′‐diaminodiphenylmethane (DDM). Modified epoxy resin composites (E51/DDM/TMBPA‐MPPO‐2OH) were prepared through a casting method, with TMBPA‐MPPO‐2OH and E51 mixed in varying mass ratios. The effects of TMBPA‐MPPO‐2OH incorporation on both the curing kinetics and final characteristics of the modified epoxy resin systems were systematically investigated. Results showed that E51/DDM/TMBPA‐MPPO‐2OH composites possessed a high glass transition temperature (Tg = 178.77 ~ 194.16°C), along with excellent thermal stability (Td5% = 355 ~ 360°C) and flexural strength (67.31 ~ 75.28 MPa). Additionally, the inclusion of TMBPA‐MPPO‐2OH reduced the dielectric constant, dielectric loss tangent, and moisture absorption rate of E51/DDM/TMBPA‐MPPO‐2OH. When the TMBPA‐MPPO‐2OH content was 20 wt%, the dielectric constant (10 MHz, 3.2), dielectric loss (10 MHz, 0.015), and moisture absorption rate (1.7%) of E51/DDM/TMBPA‐MPPO‐2OH showed reductions of 16%, 58%, and 32%, respectively, compared to the pure epoxy resin.

Flame Retardant Performance of Phosphatized Starch in Epoxy Resins: A Sustainable Approach to Enhancing Fire Safety

ABSTRACTThe imperative to protect human life and property from the threat of fires underscores the need for effective flame retardants (FRs). In response to growing calls for sustainability, bio‐based FR options have emerged, among which phosphatized starch (PS) has shown considerable promise. This study investigates the FR mechanisms and FR performance of thermally stabilized PS in epoxy resin‐based thermosets through thermo‐gravimetric analysis, thermo‐gravimetric Fourier‐transform infrared spectroscopy mass spectrometry, and cone calorimetry. PS primarily acts in the condensed phase by promoting the formation of char and an intumescent layer. Incorporating 25% of PS into the thermoset significantly reduces the peak heat release rate, total heat release, and total smoke release by 70%, 52%, and 53%, respectively. As the global pursuit of responsible and environmentally conscious fire safety solutions intensifies, exploring PS as a bio‐based FR represents a promising step toward a safer and more sustainable future.

Edgewise Compressive Properties of Ecological Sandwich Panels with Engineered Bamboo Face Sheets and Bamboo Culm Core

Bamboo is a green, renewable material with high strength and low cost, but raw bamboo has limited application in residential buildings due to its irregular shape and dry cracking. In this regard, this work proposed a novel ecological sandwich panel to explore the potential combination of engineered bamboo and raw bamboo culms. Face sheets made of glued laminated bamboo panels were bonded to the bamboo culm core via epoxy resin and mortise–tenon joints. Two groups of specimens with height-to-thickness ratios of 4.63 and 5.37 were tested through edgewise compression to investigate the failure modes, strength and rigidity. The results revealed that the specimens had no overall stability problem under axial loading, but exhibited delamination and local bulging to the face sheets. When the height-to-thickness ratio increased from 4.63 to 5.37, but still belonged to the short member range, the area of the adhesive interface increased by 16.13%, and the edgewise compressive strength and rigidity increased by 17.57% and 35.04%, respectively. This indicated that the capacity and rigidity were mainly determined by the connection strength, which was obviously affected by the manufacturing and assembly errors. Accordingly, increasing the connection strength could be helpful for improving the load-carrying capacity and ductility of such panels.

A Strategy for Designing Hierarchical Structure Flame Retardant ZM@APP for Improving Flame Retardancy, Mechanical Performance, and Smoke Suppression of Epoxy Resin

ABSTRACTImproving flame retardancy without compromising mechanical properties is a significant challenge in epoxy resin (EP) applications. In this study, an inorganic–organic hybrid flame retardant (ZM@APP) with a hierarchical structure was designed by loading the compounds with a shell‐core structure ZM (a complex of ZIF‐67 and melamine) on the surface of ammonium polyphosphate (APP) through hydrogen bonding. When the loading of ZM@APP was 10.0 wt.%, the tensile strength, flexural strength, and flexural modulus of the EP composites increased by 13.7%, 16.7%, and 87.6%, respectively, compared to pure EP. Surprisingly, modified APP also resulted in the promotion of mechanical performances while APP triggered the decreases in mechanical properties. The 10ZM@APP/EP passed the V‐0 rating in the vertical combustion test and achieved the limiting oxygen index of 28.2%. The peak heat release rate and total heat release decreased by 68.4% and 58.5%, respectively; the peak smoke release rate and total smoke production were reduced by 60.0% and 67.5%, respectively, compared to pure EP. The reason was that the triazine ring, cobalt oxide, and pyrophosphoric acid promoted the formation of contact and continuous char. This study offers a new method for preparing EP composites with enhanced flame retardancy, high mechanical properties, and low smoke release.

Stainless steel wire mesh hybridization for improved bending fatigue performance in fiber reinforced polymer sandwich structures

AbstractSandwich structures are preferred in many engineering applications where they are subjected to not only static but also variable loads. In this study, stainless‐steel wire mesh sheet hybridization was applied to very low‐density polymeric sandwich structures, and their fatigue performance under variable loading was investigated. Plain woven carbon fiber and stainless‐steel wire mesh sheet hybrid structure, epoxy resin, and closed cell polyvinyl chloride (PVC) foam (48 kg/m3) were used for the face sheets, binding matrix, and core, respectively. Specimens were subjected to three‐point bending tests, both quasi‐static and fatigue. It was found that the thickness of the stainless‐steel wire mesh sheet and the hybridization position significantly influenced fatigue life. It was also observed that the hybridization effect became more pronounced as core thickness increased. S–N curves of four configurations were obtained for a detailed fatigue analysis. In 10 mm core sandwiches, hybridization was effective at high loading levels but not at low levels, whereas in 30 mm core sandwiches, it improved performance at all load levels.Highlights Stainless‐steel wire mesh hybridization enhances sandwich fatigue performance. Quasi‐static and fatigue tests confirm improved bending performance. S–N curves provide detailed insights into fatigue life. Face sheet hybridization effects increase with greater core thickness. Fatigue‐induced cavity formation occurs in thicker cores.

Novel reactive phenolphthalein‐based polyether ketone, its scale‐up preparation and high‐efficiency toughening in epoxy resin modification

AbstractIncorporating reactive groups that can participate in epoxy cross‐linking into traditional thermoplastic toughening agents enhances the interfacial compatibility between thermoplastic and thermosetting resins, thereby improving the impact toughness of the system. In this study, hydroxyl end groups were integrated into phenolphthalein polyether ketone (PEKC) molecular chains to engage in the cross‐linking reaction during epoxy curing, significantly enhancing the toughening effect on the epoxy system. The results indicate that hydroxyl‐terminated phenolphthalein polyether ketone (PEKC‐OH) of various molecular weights can enhance the impact strength of the epoxy system (E51/MTHPA). Among these, the PEKC‐OH‐2 resin exhibited the optimal toughening effect at an addition level of 10 phr, increasing the impact strength from 11.85 to 23.46 kJ/m2, representing a 98% improvement, without compromising the operating temperature and mechanical properties of the epoxy system. Additionally, kilogram‐scale toughening agent resins were produced through scale‐up experiments of PEKC‐OH‐2 in a 50‐L polymerization reactor, validating its applicability for industrial epoxy toughening. In summary, the PEKC‐OH synthesized in this study serves as an efficient reactive thermoplastic toughening agent, offering ease of preparation, industrial producibility, and considerable application potential.Highlights Novel hydroxyl‐terminated phenolphthalein polyether ketone (PEKC‐OH). Reactive hydroxyl end groups improved compatibility with epoxy resin. PEKC‐OH formed an interpenetrating network with epoxy, boosting impact toughness. Scaled‐up of PEKC‐OH‐2 in a 50‐L reactor for industrial production. PEKC‐OH is feasible to prepare and has great application prospect.

Study on the static and pseudo-static behavior of a ceramic panel fixed with an anchor and epoxy resin adhesive

Abstract This study investigates ceramic panels’ static and pseudo-static behavior secured with an anchor and epoxy resin adhesive to enhance their load-bearing capacity and safety. The influence of different anchor implantation positions was evaluated through experimental tests and numerical simulations, focusing on the static behavior of independent ceramic panel elements and the pseudo-static response of K-1 specimens. The results demonstrate that compared to traditional adhesive bonding, mechanical fixation using an anchor and epoxy resin adhesive significantly enhanced the shear capacity of ceramic panels, with K-1 specimens showing a 48.44% improvement. This fixation method exhibited excellent seismic performance in pseudo-static tests, maintaining structural stability under large interstorey drift ratios and preventing panel detachment. These findings provide scientific data supporting advanced ceramic panel installation techniques, offering practical solutions to reduce falling incidents and improve building safety and durability.

Methods for measuring fine-scale social proximity in small mammals

Abstract There are barriers to directly observing animals that are cryptic or live in environments inaccessible to humans. Biologgers, animal-attached devices designed to collect data on animals without a human researcher present, have become useful tools for studying species that cannot be directly observed. The use of biologgers has been size-limited until recent efforts to miniaturize the technology opened up the possibility of using them on small animals. In this study, we packaged and deployed proximity logging devices (“ProxLogs” model) for use on a small, socially monogamous, semifossorial mammal, the Prairie Vole (Microtus ochrogaster), as a means to collect high-resolution data on fine-scale spatial proximity between conspecifics. First, we evaluated multiple packaging options for the devices and found that UV-curing epoxy resin containing grit (sand) was the most durable packaging material. ProxLogs recorded voles when they were within 6 cm of each other. We compared the resolution of social proximity data collected by ProxLogs to patterns of social proximity collected through livetrapping and, as expected, found that the ProxLogs generated significantly higher-resolution data than livetrapping. We also found that social proximity data collected through livetrapping significantly predicted social proximity data collected by the ProxLogs. Our findings provide proof of concept that proximity loggers, packaged with UV-curing epoxy resin, are a reliable, high-resolution method to collect 24-h social proximity data on small mammals that are otherwise difficult to observe.

Enhanced mechanical performance and failure mechanisms of woven glass fiber‐reinforced polymer composites with optimized multi‐walled carbon nanotube reinforcement

AbstractThis study investigates the mechanical enhancement of woven glass fiber‐reinforced polymer (WGFRP) composites through incorporating multi‐walled carbon nanotubes (MWCNTs). The composite matrix comprises LY556 epoxy resin and HY951 hardener in a 10:1 ratio, with MWCNTs incorporated at varying weight percentages (0, 0.5, 1, 1.5, and 2 wt%). The effect of MWCNT concentration on ultimate tensile strength (UTS), elongation, peak load, flexural strength, and modulus of elasticity was systematically analyzed. Scanning electron microscopy (SEM) examined fracture morphology, fiber‐matrix interfacial adhesion, and failure mechanisms. The results indicate that the optimal MWCNT concentration of 1 wt% yields superior mechanical properties with UTS of 135 MPa, flexural strength of 178.09 MPa, and flexural modulus of 20,299.16 MPa. The improvements were attributed to the uniform dispersion of MWCNTs, enhancing interfacial bonding and stress transfer. However, at higher concentrations (≥ 1.5 wt%), MWCNT agglomeration leads to stress concentration points, reduced interfacial adhesion, and decreased mechanical performance. SEM analysis revealed failure modes of fiber pullout, delamination, void formation, and brittle fracture, particularly at higher MWCNT loadings. These findings highlight the potential of MWCNT‐reinforced WGFRP composites in aerospace, automotive, and sports industries, where high strength, stiffness, and lightweight characteristics are critical.Highlights Optimal MWCNT (1 wt%): UTS 135 MPa, flexural 178.09 MPa, modulus 20,299 MPa. High MWCNT (>1 wt%): Agglomeration reduces adhesion, weakening properties. Failure Modes: Fiber pullout, delamination, voids, brittle fracture observed. Fabrication: Hand layup, sonication, ASTM D3039 (tensile), ASTM D790 (flexural). Applications: High strength, lightweight, ideal for aerospace, auto, sports.

Synthesis and Mechanical Behaviour of Corn Husk and Sisal Fibre Reinforced Hybrid Polymer Composites

Abstract This paper presents the synthesis and mechanical characterization of hybrid polymer composites reinforced with sisal and corn husk fibres using vacuum bag moulding. The selection of these natural fibres was guided by their availability, low cost, and biodegradability. Composite specimens were fabricated with fibre weight fractions of 5%, 10%, 15%, 20%, and 25%, employing epoxy resin as the matrix material. Mechanical tests including tensile, flexural, impact, and wear evaluations were conducted. The tensile strength increased from 32 MPa to 45 MPa, while the tensile modulus rose from 2.5 GPa to 3.5 GPa with increasing fibre content. Similarly, flexural strength improved from 60 MPa to 85 MPa, and the flexural modulus from 3.0 GPa to 4.0 GPa. Wear rate decreased from 0.8 mm³/Nm to 0.3 mm³/Nm, and both impact resistance and energy absorption capacity increased from 15 J to 35 J. SEM analysis revealed uniform fibre dispersion and strong interfacial bonding between the fibres and the matrix. These enhancements in mechanical performance indicate that the developed composites are environmentally friendly alternatives to conventional synthetic composites, with potential applications in construction, automotive panels, and sports equipment.

Thermo-chemical coupled finite element modeling of epoxy resin frontal polymerization: effects of temperature-dependent properties and boundary materials

Frontal polymerization (FP) offers an efficient and energy-saving alternative to conventional curing methods for epoxy resins. In this study, a transient thermo-chemical coupled heat-transfer model (V-model) was developed using temperature-dependent thermophysical properties. Curing kinetics parameters were first determined by fitting data from non-isothermal differential scanning calorimetry of a BADGE-based resin. Compared to a constant-property model, accounting for changes in thermal conductivity and specific heat capacity significantly improved the accuracy of the predicted temperature profiles, aligning more closely with experimental observations. The validated V-model was then extended to evaluate the impact of boundary materials with different thermal conductivities on FP behavior. Experiments confirmed that high-conductivity boundaries facilitate preheating of unreacted resin, thereby promoting faster polymerization-wave propagation. Meanwhile, insulating boundary materials minimize heat loss, sustaining the FP reaction. This combined computational–experimental approach provides deeper insights into the heat-transfer mechanisms governing epoxy resin FP and guidance for optimizing industrial process parameters.