ABSTRACT:
Footwear soles play a critical role in providing protection, comfort, traction, and moisture management under demanding conditions. Inadequate Adhesion between polyurethane midsoles and vulcanized rubber outsoles remains a critical failure mode in high‑performance footwear (safety and combat), leading to delamination and reduced service life. Three commercially available non-woven fabrics manufactured in different countries were incorporated into rubber-fabric-PU sandwich structures. Unlike earlier studies that examined rubber-fabric or fabric-PU adhesion in isolation, this work systematically compares three fabrics within an integrated rubber-fabric-polyurethane sandwich architecture, providing new insight into interlayer selection for footwear sole manufacturing. Physical properties, including tensile strength, peel strength, hardness, abrasion resistance, and flex resistance, were evaluated in accordance with relevant ISO standards. Scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) were carried out to investigate thermal stability and interfacial morphology. SEM analysis revealed more continuous rubber penetration and fewer interfacial voids for the German polyester fabric, consistent with its higher peel strength, while the Pakistani polypropylene fabric exhibited higher tensile strength. TGA analysis complemented the SEM findings, confirming that all composites exhibited comparable thermal stability within the operating temperature range. All composites met the requirements of EN ISO 20345:2022 for safety footwear. These findings show appropriate selection of a non-woven fabric interlayer that significantly improves rubber-PU adhesion, offering a viable alternative to chemical treatments and adhesives in high-performance footwear sole manufacturing.

Keywords: vulcanized rubber; polyurethane; non-woven fabric; shoe sole; bonding strength

How to Cite this paper?

APA- Style
Ali R., Iqbal S. S., (2026) Enhancement of Bond Strength Between Polyurethane and Vulcanized Rubber Using Non-Woven Fabric Interlayers for Footwear Soles. Pakistan Journal of Chemistry, 16(3), 150-160. https://doi.org/10.15228/2026.v16.i4.p.150-160.

ACS Style
Ali R., Iqbal S. S., Enhancement of Bond Strength Between Polyurethane and Vulcanized Rubber Using Non-Woven Fabric Interlayers for Footwear Soles. Pakistan Journal of Chemistry, 16(3), 150-160. https://doi.org/10.15228/2026.v16.i4.p.150-160.

AMA Style
Ali R; Iqbal S. S; Enhancement of Bond Strength Between Polyurethane and Vulcanized Rubber Using Non-Woven Fabric Interlayers for Footwear Soles. (2026) Pakistan Journal of Chemistry, 16(3), 150-160. https://doi.org/10.15228/2026.v16.i4.p.150-160.

Chicago/Turabian Style
Ali R, Iqbal S S, Enhancement of Bond Strength Between Polyurethane and Vulcanized Rubber Using Non-Woven Fabric Interlayers for Footwear Soles. (2026) Pakistan Journal of Chemistry, 16(3), 150-160. https://doi.org/10.15228/2026.v16.i4.p.150-160.

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