Chemical and Mechanical Characterization of Bauhinia Racemosa Fibre and its Potential Textile Applications

Abstract

Bauhinia racemosa is an underexplored bast fibre–yielding tree whose bark provides a moderately strong, low density fibre with promising technical and functional attributes. This review synthesizes current knowledge on the extraction, morphology, chemical composition, and mechanical behaviour of B. racemosa bark fibre, along with its existing and potential textile applications. The fibre exhibits typical lignocellulosic characteristics, with high cellulose and comparatively low lignin and wax content, supporting favourable strength to weight ratios and good interfacial bonding in composites. Microstructural studies reveal multicellular fibre bundles with a rough surface conducive to mechanical interlocking, though short, fragile staple length constrains conventional spinning. Mechanical evaluations indicate medium tensile strength and stiffness at the fibre/strand level and significant improvements in tensile, flexural and impact properties when used as reinforcement in polyester and epoxy composites at optimized loadings. Traditional and experimental applications already include ropes, cords, and Ayurvedic sutures, with the latter demonstrating acceptable tensile performance and biocompatibility. The presence of tannins and flavonoid rich phytochemicals in bark and associated tissues suggests additional scope for bio functional textiles, including antimicrobial or wound care materials. Limitations such as fibre shortness, processing variability, and limited standardized textile data are highlighted, alongside research needs in retting optimization, yarn development, bio functional finishing and life cycle assessment. Overall, B. racemosa emerges as a niche, sustainable bast fibre suited for ropes, sutures, agro textiles, geotextiles and composite based technical textiles, rather than mainstream apparel applications.

Introduction

Bauhinia racemosa is a small deciduous tree widely found in India and other tropical regions. Its bark yields a strong bast fibre traditionally used for ropes, cords, torches, and cattle tying. In Ayurvedic practice, its inner bark fibres—known as “Ashman taka”—are used as suturing material due to their fineness and tissue compatibility. Beyond mechanical uses, the plant contains bioactive compounds such as tannins and flavonoids, giving it astringent, antimicrobial, and wound-healing properties. This dual role makes it promising for functional and biomedical textile applications.

Fibre Extraction and Characteristics

The fibre is extracted from stem bark using simple mechanical and water-based methods such as peeling, sun drying, beating, and manual separation. It exhibits typical bast fibre morphology with multicellular bundles and rough surfaces that enhance mechanical interlocking in composites.

Key physical properties:

• Length: Short and fragile (10–12 cm), limiting long-staple spinning.

• Diameter: 0.05–0.40 mm depending on processing.

• Colour: Creamish white with relatively smooth texture.

• Surface roughness supports composite bonding but may require interface treatment for high-performance applications.

Chemical Composition

The fibre is lignocellulosic, primarily composed of:

• Cellulose (~60–70%)

• Lignin (~10–15%)

• Minor hemicellulose, waxes, and ash

High cellulose and low lignin content favor mechanical strength and dyeability. The presence of phenolics and tannins contributes potential antimicrobial and bioactive properties. Thermal behavior is similar to other bast fibres, suitable for moderate-temperature textile and composite processing.

Mechanical Properties

• As suture thread, tensile strength is about 8.8 MPa, adequate for skin closure.

• Compared to some agricultural fibres (banana, elephant grass), it shows higher strength and lower density.

• In polyester and epoxy composites:

  • Tensile strength ≈ 18.8 MPa

  • Flexural strength ≈ 34.1 MPa

  • Performance improves with optimal fibre loading.

• Hybrid composites (e.g., with glass fibre) show enhanced mechanical properties.

Overall, it is a medium-strength bast fibre, suitable for ropes, composites, and semi-structural applications.

Applications

1. Traditional Cordage: Ropes, ladder cords, torches.

2. Biomedical Textiles: Biodegradable sutures, wound-closure materials.

3. Apparel & Home Textiles (Limited): Rustic yarns, mats, rugs (due to short fibre length).

4. Geotextiles & Agrotextiles: Erosion control mats, biodegradable nets.

5. Technical Textiles & Composites: Automotive interiors, panels, construction components.

Advantages

• Renewable and widely available.

• Moderate strength with low density.

• Potential bioactivity from phytochemicals.

• Traditional acceptance and demonstrated biocompatibility.

Limitations

• Short, fragile fibres unsuitable for fine yarn spinning.

• Limited standardized textile property data.

• Moisture sensitivity typical of natural fibres.

• Manual extraction methods limit large-scale processing.

Conclusion

Bauhinia racemosa bark fibre is an emergent bast fibre with documented use in traditional cordage and sutures and growing interest as reinforcement in polymer composites. Chemically, it is a high cellulose, low lignin lignocellulosic fibre, structurally similar to other bast fibres but distinguished by its moderate strength, lower density and the presence of tannin rich, bioactive components. Mechanical studies on short fibre polyester and epoxy composites demonstrate adequate tensile and flexural properties, particularly at optimised fibre loadings around 40 wt%, supporting its suitability for lightweight technical products. From a textile perspective, the fibre’s coarseness, short length and fragility limit its immediate use in mainstream apparel, but it is well positioned for ropes, cords, sutures, agrotextiles, geotextiles and composite based technical textiles. With further research into extraction, spinning, finishing and biofunctionalisation, B. racemosa could evolve from a locally used bark fibre to a niche sustainable fibre for specialized textile applications, especially where biodegradability and functional phytochemistry are valued.

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Copyright

Copyright © 2026 Angel D., Dharshini M., Dharshini R., Gopika S., Janani S., Monika S., Dr. E. Devaki. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.