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@article{209221,
        author = {Aparna Kulkarni and Vineet Kumar Choudhary},
        title = {Citric Acid Treatment of Natural Fibers for Enhanced Strength in Polymer Composites: A Critical Review},
        journal = {International Journal of Innovative Research in Technology},
        year = {2026},
        volume = {13},
        number = {5},
        pages = {932-943},
        issn = {2349-6002},
        url = {https://ijirt.org/article?manuscript=209221},
        abstract = {Natural fiber reinforced polymer composites (NFRPC) offer sustainable alternate to synthetic composites, yet their industrial applications are often hindered by inherent hydrophilicity of natural fibers. Hydrophilicity of natural fibers results in meager interfacial adhesion with hydrophobic polymer matrices like polyester. This review critically examines the effectiveness of citric acid (CA), a non-toxic and biodegradable organic acid, as a surface modifier to address these compatibility challenges. The primary mechanism of CA treatment involves esterification, where carboxyl group of CA react with hydroxyl groups of fibers to form ester linkages, significantly reducing water absorption and increasing surface roughness for improved mechanical strength with better interlocking. Evidence from various polymer systems (Polylactic acid PLA, Polycaprolactone PCL and Epoxy) indicates that CA treatment consistently improves tensile strength, yield strength and modulus. However, crosslinking induced by CA can increase fiber brittleness, leading to the reduction of impact strength. Furthermore, a significant research gap has been identified regarding a specific application of CA treated fibers in unsaturated polyester laminates, as most of the current data is derived from other matrices or CA used as a binder. The paper concludes that the CA is viable, ecofriendly alternative to toxic alkaline treatments and the future research can focus on optimising treatment parameters to balance tensile strength with toughness in polyester systems.},
        keywords = {Natural fibers, Citric acid, Surface modification, Polyester composites, Interfacial adhesion},
        month = {October},
        }