Biosourced Natural Latex–Okra Fabric Composites: Manufacturing, Dye-Dependent Mechanical Behavior, and Environmental Aging Response

<title>Abstract</title> <p>Natural-fibre composites with elastomeric matrices offer an attractive route toward biosourced, flexible, and moisture-resistant materials for textile-based applications, yet plant fibres that resist conventional spinning remain underexploited as structural reinforcements. This study reports the manufacturing and characterization of a biocomposite combining a woven okra (Abelmoschus esculentus) bast-fibre fabric with a natural-rubber latex matrix, produced in two dye formulations (red and black). Individual fibres, unsuitable for conventional spinning, were converted into cohesive twisted cords (mean diameter 0.50 ± 0.02 cm, tenacity 5.0 ± 0.3 cN/tex) and manually woven into a plain-weave fabric (areal density 348.8 g/m², total cover factor 0.332), which was subsequently impregnated with dyed natural-rubber latex (total solids content 46.9%, dynamic viscosity 1.14 mPa·s). The resulting bio-composites exhibited 100% water impermeability in both formulations. The red formulation showed markedly higher stiffness and strength than the black formulation (Young’s modulus +87.8%, maximum stress +64.7%) at the cost of reduced elongation at break (−21.5%) and lower water absorption (−21.2%), establishing a clear formulation-dependent mechanical trade-off whose underlying mechanism (interfacial, morphological, or pigment-dispersion effects) is not yet isolated. After 30 days of environmental aging, this ranking was not preserved: the black composite retained higher stress than the red composite after high-humidity exposure (98% RH), while the red composite retained a comparatively higher modulus, indicating that the formulation offering the best as-produced performance is not necessarily the most durable one. These results demonstrate that okra bast fibres can be converted into a functional latex-based textile composite through a fully manual, low-technology processing route, and highlight that dye selection and environmental exposure jointly govern in-service performance a finding directly relevant to the design of biosourced, water-resistant textile products.</p>