The quest for bioderived resins and eco-friendly lightweight materials having remarkable mechanical performance is ubiquitous in scientific reports. In this work, we report a strong and tough biobased resin of esterified Polyvinyl alcohol-Citric acid-Lignin (E-PCL) suitable for nanocellulose fiber-reinforced polymer composites. The mechanical properties of the resin were optimized by varying the volumetric concentration of citric acid and subsequently esterified at 180°C. At 30% citric acid content, the esterified resin showed dramatic improvement in tensile strength (269.8%), toughness (1222.8%), Elastic modulus (273.5%), and hydrophobicity (48.5%). The adhesion strength of the resin to cellulose film was 31.92 MPa making it appropriate for green cellulose-based fiber-reinforced polymer composites. To validate our concept, three wet-spun nanocellulose filament was knit into mats on a loom and applied in composite fabrication through hand-layup and hot press. The lightweight yet strong and stiff structural composite displayed a record high flexural strength of 363.42 MPa and flexural modulus of 39.89 GPa with a water contact angle of 93.4°. Insights from this report offer a promising platform for utilizing environment-friendly resins and nanocellulose to engineer lightweight and robust structural composites for automotive, aerospace, and structural applications.
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