Bartosz Weclawski

This study explores the impact of alkali treatment on the physical, thermal, flexural, and thermo-mechanical properties of Borassus flabellifer husk fiber-reinforced epoxy composites in accordance with standards. Using the hand layup method, composites were fabricated with 10% (wt.) untreated and alkali-treated fibers (0.25–2 hours). SEM analysis confirmed improved fiber-matrix adhesion, leading to enhanced properties. Treated fiber composites exhibited reduced moisture regain (0.57−1.28%) and water absorption (0.59−1.55%), indicating superior moisture resistance. Thermal stability increased with alkali treatment, with integral process decomposition temperature (IPDT) reaching 547°C for 2-hr treated fibers. The glass transition temperature (Tg) peaked at 94.5°C for the 0.5-hr treated Borassus fiber-reinforced epoxy (0.5TBHFE). Flexural modulus (up to 3.2 GPa) and strength (up to 108.7 MPa) exceeded many conventional bio-fibers-reinforced composites, making them rational for structural applications. Dynamic mechanical analysis showed enhanced damping properties (tan δ up to 1.21), improving energy dissipation and impact resistance. Overall, 0.5TBHFE offered an optimum balance between stiffness and damping, making it suitable for aerospace and automotive applications. This study highlights the potential of Borassus husk fibers as a sustainable reinforcement alternative, though further optimization and industrial processing are needed for broader application.

Natural fibers from renewable resources offer a sustainable as well as biodegradable alternative to synthetic reinforcements in polymer composites. This study investigates the thermal and mechanical behavior of Borassus husk fiber-reinforced epoxy composites, fabricated via the hand layup method. The fibers were alkali-treated with 5% sodium hydroxide (NaOH) for varying durations (0.5 to 2 h) to improve interfacial bonding. Thermal and dynamic mechanical properties were analyzed using thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). Alkali treatment enhanced thermal stability, as indicated by increased char residue (up to 9.43%) and higher integral process decomposition temperatures (IPDT), with the 1-h treated sample achieving the highest IPDT of 554°C. Compared to neat epoxy and other natural fiber composites, Borassus fiber composites exhibited superior energy dissipation, stiffness, and mechanical strength. Although the glass transition temperature (Tg) decreased from 149°C in neat epoxy to between 122°C and 140°C in treated composites, the values remained competitive. The 0.75TBHFE demonstrated the best overall performance, with optimal storage modulus, improved damping and minimal mass loss. These findings underscore the potential of alkali-treated Borassus husk fiber/epoxy composites for high-performance applications, such as aerospace, while promoting environmental sustainability and supporting net-zero carbon emission goals.

Natural fibers from renewable resources present a sustainable and biodegradable alternative to synthetic reinforcements. This study explores the thermal and mechanical performance of Borassus husk fiber/epoxy composites, fabricated using a hand layup process with 5% NaOH alkali treatment at varying durations (0.5–2 h). Thermal and thermo-mechanical properties were assessed using thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) followed by scanning electron microscopy (SEM) analysis, and outgassing tests. Results show that alkali treatment significantly improves the composites' thermal stability, indicated by increased char content (up to 8.11%) and higher integral process decomposition temperature (IPDT), with the 0.75-h treated sample reaching 525°C. The composites also demonstrated enhanced energy dissipation and stiffness compared to neat epoxy (NE) and other natural fiber-based composites. Glass transition temperature (Tg) decreased from 150°C (NE) to 126°C–137°C for treated samples, yet remained higher than those reported for other bio-fiber composites. The 0.75TBHFE sample exhibited the best balance between stiffness and damping, supported by improved phase angle and fiber–matrix adhesion observed in SEM analysis. Outgassing results showed an increase in total mass loss (0.11%–0.53%) compared to NE (0.26%), though still within acceptable limits for thermal stability. These findings highlight the potential of alkali-treated Borassus husk fiber/epoxy composites as high-performance, sustainable materials suitable for aerospace applications. Further research is recommended to address property variability in natural fibers and to develop efficient supply chains for large-scale industrial production.

Natural fibers from renewable resources provide a sustainable alternative to synthetic reinforcements. This study examines the thermal and mechanical properties of Borassus husk fiber/epoxy composites, fabricated using untreated and alkali-treated fibers through the hand layup process. Fibers were treated with sodium hydroxide (NaOH) for 0.25–2 hours, and their thermal and thermo-mechanical properties were analyzed through thermogravimetric analysis (TGA) according to ASTM E2550, and dynamic mechanical analysis (DMA) was conducted adhering ASTM D5418–01 followed by scanning electron microscopy (SEM) analysis. Alkali treatment significantly enhanced thermal stability, as indicated by increased char content (11.5%) and higher integral process decomposition temperature (IPDT) values, with the 0.75-hour treated fiber/epoxy achieving the highest value (580°C). The composites exhibited superior mechanical stiffness and energy dissipation compared to neat epoxy (NE) and other bio-fiber composites. The glass transition temperature (Tg) increased significantly for 0.5TBHFE (94.6°C). Additionally, storage modulus and tanδ improved, with 0.5TBHFE offering the best stiffness–damping balance. A 34% reduction in total mass loss clearly indicates improved thermal stability, which is further supported by SEM images showing enhanced fiber–matrix interlocking. These findings highlight alkali-treated Borassus husk fiber composites can be promising structural materials for aerospace and automotive applications, contributing to eco-friendly and sustainable development.

The demand for materials that combine high thermal stability and environmental sustainability is growing in modern engineering. While synthetic fibers are effective, their environmental impact often undermines sustainability goals. This study explores the potential of Borassus flabellifer fruit husk, typically discarded as agricultural waste in Bangladesh, as a bio-fiber alternative for thermal insulation applications. The research investigates the morphological, chemical, and thermal properties of the husk after alkali treatment with sodium hydroxide (NaOH) for varying durations. The results show that alkali treatment significantly enhances the thermal properties of Borassus husk. Notably, char content increased by up to 32%, surpassing other biofibers such as hemp, sisal, jute, and kenaf. The integral process decomposition temperature (IPDT) was found to be up to 30% higher than the untreated husk fiber, indicating improved thermal stability. Additionally, specific heat capacity (Cp) decreased by approximately37%, correlating with an increase in integral process decomposition heat (IPDH). Scanning electron microscopy (SEM) analysis revealed that treated husks had a rougher and cleaner surface, which may improve thermal insulation properties by creating more voids and enhancing adhesion in composite materials. Fourier Transform Infrared Spectroscopy (FTIR) analysis showed reduced and shifted hemicellulose peaks, consistent with lower moisture absorption, as confirmed by thermogravimetric analysis (TGA)and differential scanning calorimetry (DSC). Optimal results were observed in samples treated for 0.25 and 0.75 h, suggesting that alkali-treated Borassus husk could serve as an alternative eco-friendly material for energy-efficient and sustainable engineering applications

Advancements in modern engineering design require materials that maintain thermal and mechanical stability under diverse conditions. To promote sustainability and eco-friendliness, researchers are increasingly exploring natural alternatives to synthetic fibers. Among bio-fibers, Borassus flabellifer fruit shell (husk), has no other uses than disposal or waste-to-energy in Bangladesh. While other parts of the plant, such as, the fruit and leaf stalks, are commonly utilized for fine and coarse fibers, the husk fiber remains underexplored. Hence, this study investigates exclusively the thermal properties of untreated Borassus husk fibers according to ASTM E2550 and ASTM E1269-11 standards and evaluates their curved specimens' mechanical properties using ASTM D2344 and ASTM D6415 standards. The findings reveal that raw Borassus husk fibers exhibit remarkable thermal stability, characterized by a higher char content and an elevated integral process decomposition temperature compared to the its fine and coarse fibers. During cellulose decomposition, the husk fibers demonstrate a specific heat capacity of 1.6 J/g°C, which surpasses that of coconut fibers. Additionally, mechanical testing indicates that the curved husk possesses competitive inter-laminar tensile strength and short-beam strength, comparable to glass fiber-reinforced polymers, curved woven glass/polyester composites and some bio-composites. Fracture surface analysis reveals a unique morphology, featuring non-uniform, cross-linked, and porous tubular structures, which contribute to the material's distinct thermal and mechanical properties. These results highlight the potential of untreated Borassus husk fibers as a viable material for engineering applications. Utilizing this underexplored resource could promote the cultivation and preservation of B. flabellifer trees, thereby encouraging sustainable development.

Bio-based materials are gaining importance in engineering due to their availability, recyclability, and eco-friendliness. Among them, Borassus flabellifer (Palmyra palm) fruit shell (husk) is an underutilized biofiber in Bangladesh, currently limited to disposal or waste-to-energy applications despite its potential for high-value uses. This study explores the physical, chemical, and microstructural properties of untreated Borassus flabellifer husk to evaluate its suitability as a sustainable material for engineering applications. The physical properties, including density, water absorption, moisture regain, and porosity, were assessed according to BS EN ISO 1183-1:2019, ASTM D750, ASTM D2654-22, and ISO 2738 standards. The husk was found to be significantly lighter than its fine as well as coarse fibers and conventional natural fibers like jute, flax, and sisal, making it ideal for lightweight engineering designs. FTIR analysis (qualitatively) revealed the presence of cellulose, hemicellulose, and lignin, which contribute to its mechanical strength, water absorption, and thermal insulation properties, respectively. SEM analysis further demonstrated a cross-linked, porous, and tubular fiber structure, enhancing its thermal and sound insulation features. The findings suggest untreated Borassus flabellifer husk can be a promising alternative for applications requiring lightweight, thermally, and acoustically insulating materials. While its moisture and water resistance outperform some biofibers, chemical treatments could enhance these properties further. To maximize its potential, efficient collection and supply chain systems are essential for industrial-scale production. Harnessing this abundant resource could support sustainable development while encouraging the cultivation and preservation of Borassus flabellifer trees.

This study investigates the effect of elevated temperatures on the mechanical properties of Borassus husk fiber‐reinforced epoxy composites, focusing on their potential for aerospace internal structural components. Composites were fabricated using Borassus husk fibers incorporated with epoxy resin, including 5% alkali‐treated fibers (treated for varying durations) to improve adhesion. Dynamic Mechanical Analysis (DMA) was performed according to ASTM D5418‐01 standards. Results revealed that both untreated and alkali‐treated fibers enhanced the storage modulus of the composites. The highest loss modulus was observed for the composite with 1‐h treated fibers. The glass transition temperature ( T g ), determined from the peak loss modulus, was significantly higher (84°C–89°C) for treated Borassus husk fiber/epoxy composites compared to neat epoxy and composites reinforced with other natural fibers, such as flax, jute, palm sprout, date palm, sisal, and kenaf. Alkali treatment also notably increased the tan δ (damping factor), with the highest value (1.2) for the 0.75‐h treated fiber composite, outperforming several other natural fiber‐epoxy composites. Cole–Cole plots indicated improved resin‐fiber adhesion for composites containing 0.75‐ and 1‐h treated husk fibers. Phase angle data confirmed enhanced energy dissipation and viscoelastic behavior. Thermo‐mechanical stability improved, with the 0.75‐h treated fiber composite showing the lowest total mass loss (0.4%). Overall, alkali‐treated Borassus husk fiber composites exhibited superior mechanical stiffness, damping capacity, and thermal stability, making them ideal for aerospace and automotive applications requiring strength, impact resistance, and sustainability. It will also contribute to achieving the “net‐zero” target established in the 2015 Paris Agreement.

This study investigates the effect of Electromagnetic Field Treatment (EMFT) on the mechanical properties of polyacrylonitrile (PAN)-based single carbon fibres, which are critical materials in high-performance composites widely utilised in the aerospace and automotive sectors due to their superior strength and stiffness. Carbon fibres were subjected to controlled electromagnetic field exposure, with both treated and untreated fibres rigorously evaluated through tensile testing. The treated fibres exhibited a notable 6.12% increase in yield strength, along with a substantial improvement in tensile modulus compared to the control samples. Scanning Electron Microscopy (SEM) analysis revealed a smoother surface morphology in the treated fibres, potentially contributing to enhanced flexibility and a reduction in microscale defects. These findings suggest that EMFT may serve as an effective technique for optimising the mechanical performance of carbon fibres, thereby enhancing their suitability for advanced applications.

Fire and mechanical performances of a bio-based flax/furan resin composite are evaluated and, in order to assess their commercial potential, compared with those of conventional carbon/glass fiber-reinforced composites. Fire retardant (FR) variants of flax/furan were obtained by adding FRs to the resin and using (i) flax or (ii) FR-treated flax fabrics. With (i), the fire hazard of the composite could be reduced to minimum, without detrimental effect on the mechanical properties. However, use of FR-flax fabric (ii) led to impairment of mechanical properties. This indicated that for optimized fire and mechanical properties, use of a FR in the resin matrix suffices; there is no advantage in using a FR-treated flax fabric. Natural aging of the samples for 10 years followed by water aging indicated that water absorption in flax/furan composites was much higher than in comparable carbon/epoxy composites. While there was evidence of released acidic components such as acetic acid, oxalic acid, and so forth, in flax/furan composites, mainly from oxidative degradation of furan resin, there was no evidence of leaching of FR additives from the matrix. However, FR treatment of flax fabric affected the fiber-matrix interfacial adhesion, leading to considerable water absorption during aging and disintegration of the reinforcement.Highlights Furan resins are naturally fire retardant, burn only under forced combustion. FR flax/furan composites obtained by adding FRs to the resin or the flax fabric. FR treatment of the flax impairs mechanical properties and water tolerance. FRs in the resin neither affect mechanical properties nor leach out in water.
Fabrication of fire retardant (FR) flax/furan composites by adding FR to the resin and using FR-treated flax fabric, and their fire safety indices as compared to conventional carbon/glass fibre - reinforced composites. image