This study investigates the effect of alkali treatment on the physical, thermal, flexural and thermos-mechanical properties of Borassus husk fibre-reinforced epoxy composites according to different authorized standards. Composites were fabricated using the hand layup process with untreated and alkali-treated Borassus fibres (0.25-2 hours treatment duration). The results revealed that alkali treatment significantly improved fibre-matrix adhesion, aided by scanning electron microscopic (SEM) images, leading to enhanced composite performance. The treated fibre composites exhibited lower moisture regain (0.57%-1.28%) and water absorption (0.59%-1.55%) compared to untreated composites, demonstrating improved moisture resistance. Thermal stability increased with alkali treatment, as evidenced by higher integral procedural decomposition temperature (IPDT) values, reaching 547°C for 2-hour treated fibre composites. Additionally, the glass transition temperature (Tg) improved, peaking at 94.5°C for 0.5-hour treated fibre/epoxy. Mechanical properties, including flexural modulus (up to 3.2 GPa) and strength (up to 108.7 MPa), surpassed many conventional bio-fibre composites, making these composites suitable for structural applications compared to existing conventional bio-fibres based composites. Dynamic mechanical analysis indicated superior damping properties (tanδ, up to 1.21), highlighting their enhanced energy dissipation and impact resistance. Among the treated composites, the 0.5-hour alkali-treated Borassus husk fibre/epoxy composite (0.5TBHFE) demonstrated an optimal balance between stiffness and damping, making it a promising material for aerospace and automotive applications. The study underscores the potential of Borassus husk fibres as a sustainable reinforcement alternative in high-performance composite applications. However, further optimization and industrial-scale processing strategies are required to fully harness their potential.

Bio-based materials play a significant role in developing efficient engineering materials because of availability, recyclability and eco-friendliness. Products from Borassus flabellifer are found in both urban and rural locations in Bangladesh, and its fruits, leaf stems, and leaves are utilised in domestic applications, while some, mainly the fruit shells (husk), are discarded as agricultural waste. The objective of this study is to characterise the physical and chemical properties of the Borassus husk fibre experimentally, and it has been found that the density of the husk fibre is 0.74 g/cm 3, water absorption is 47.25%, moisture regain is 4.41%, and porosity is 34.58%. Scanning electron microscopy (SEM) analysis reveals cross-linked, non-uniform, cylindrical tubular fibers. Fourier transform infrared spectroscopy (FTIR) confirms the presence of hemicellulose, cellulose, lignin, and other components, aligning with the composition of natural bio-fibers such as jute, sisal, and flax. This indicates the material’s potential as an alternative natural fiber for lightweight engineering applications.

This study examines the impact of elevated temperatures on the mechanical properties of Borassus husk fibre-reinforced epoxy composites, focusing on the effects of alkali treatment (5% NaOH) on the fibres with varying treatment durations. Dynamic Mechanical Analysis (DMA) was conducted according to ASTM 5418-01 standards. The results showed that both untreated and alkali-treated fibres increased the storage modulus of the composites. The loss modulus significantly increased only for the alkali-treated composites, where the 1-hr treated fibre composite show the highest value. The glass transition temperature (Tg) of neat epoxy was 82 °C, which increased to 89 °C for composites with 0.75-hr treated fibres but decreased to 79 °C for untreated fibres. The tan δ (damping factor) also increased significantly with alkali treatment, with the highest value (1.2) observed for the 0.75-hr treated fibre composite, 33% higher than neat epoxy (0.9). Cole-Cole plots revealed improved resin-fibre adhesion for composites incorporated with 0.75 and 1 hour treated husk fibre. Phase angle data confirmed enhanced energy dissipation and viscoelastic properties in the treated fibre/epoxy composites. Furthermore, the total mass loss (TML) was the lowest for the 0.75-hr treated fibre/epoxy composite (0.4%), about 33% lower than neat epoxy, indicating better thermo-mechanical stability. Overall, alkali-treated Borassus husk fibre composites demonstrated superior mechanical stiffness, damping capacity and thermal stability compared to neat epoxy, making them promising materials for applications in aerospace and automotive industries, where performance, vibration reduction and sustainability are essential.

The quest for materials combining high thermal stability with environmental sustainability is intensifying in modern engineering. Synthetic fibres, while effective, often undermine sustainability goals due to their adverse environmental impact. This study explores the potential of Borassus flabellifer fruit shell (husk), typically discarded as agricultural waste in Bangladesh, as a bio-fibre alternative for thermal insulation applications. This work investigates the morphological, chemical, and thermal properties of the husk following alkali treatments with 5% sodium hydroxide (NaOH) of varying durations. The findings demonstrate that alkali treatment significantly enhances the thermal properties of Borassus husk, with observed increases in char content from 25% to 32% and Integral decomposition process temperature (IDPT) ranging from 905 to 1048 °C, which is around 12-30% higher than its untreated fibre, indicating enhanced thermal stability. Additionally, these treatments resulted in a reduction in specific heat capacity (Cp), which may be corresponded with an increase in integral process decomposition heat (IPDH). Scanning electron microscopy (SEM) analysis revealed that treated husks exhibit a rougher and cleaner surface, likely enhancing their adhesion properties in composite preparation. Fourier Transform Infrared Spectroscopy (FTIR) analysis supported these findings, showing reduced hemicellulose peaks, which align with lower moisture absorption as confirmed by thermogravimetric analysis (TGA). The optimum results were particularly observed in samples treated for 0.25 hour and 0.75 hour, indicating that Borassus husk treated with alkali for short durations could be an effective material for advanced engineering applications, which would promote eco-friendly, energy-efficient, and sustainable development.

Advancements in modern engineering designs require materials that exhibit thermal and mechanical stability under varying conditions. To promote sustainability and eco-friendliness, researchers are increasingly exploring natural alternatives to synthetic fibres. Among these, Borassus flabellifer fruit shell (husk), a material often discarded as waste in Bangladesh, holds

Bio-based materials play a significant role in developing efficient engineering materials because of availability, recyclability and eco-friendliness. Products from Borassus flabellifer are found in both urban and rural locations in Bangladesh, and its fruits, leaf stems, and leaves are utilised in domestic applications, while some, mainly the fruit shells (husk), are discarded as agricultural waste. The objective of this study was to characterize the physical and chemical properties of the Borassus husk fibre experimentally, and it has been found that the density of the husk fibre is 0.74 g/cm 3 , water absorption is 47.25%, moisture regain is 4.41%, and porosity is 34.58%. While scanning electron microscopy (SEM) outcomes show cross-linked, non-uniform, and cylindrical-shaped tubular fibre, fourier transform infrared spectroscopy (FTIR) shows the presence of hemicellulose, cellulose, lignin, and other components. Hence, this can be used as an alternative potential natural fibre for lightweight engineering designs.