Enhancing the hydrophobicity and mechanical integrity of lignocellulosic paper through synergistic integration of terpene-phenolic resin and phosphate waste rock.

This study presents a sustainable approach for producing high-performance paper materials by utilizing polysaccharide-rich agricultural residues and inorganic mining by-products. Date palm fibers were chemically and mechanically treated to lower lignin content and enrich cellulose, thereby increasing fiber crystallinity and enhancing interfacial reactivity. These cellulose-enriched fibers served as the foundation for a reinforced paper structure incorporating phosphate waste rock (PWR), assessed here for the first time as a functional additive in papermaking. PWR, rich in calcium and magnesium oxides, interacts with polysaccharide hydroxyl groups, promoting hydrogen bonding and strengthening fiber cohesion. To further modify the surface, a bio-based terpene phenolic resin (TPR) was applied as a coating, introducing additional hydrogen bonds and potential ester linkages with exposed polysaccharide chains. Thermocompression further densified the material and enhanced internal bonding. The resulting paper demonstrated remarkable properties, including a water contact angle of 120° after 60 seconds, and significant gains in rigidity (125%), and tensile strength (74%), along with an increase in ductility (50%). The combined use of phosphate mining by-products, terpene phenolic resin, and thermocompression improves the morphological, thermal, mechanical, and barrier characteristics of cellulose-based materials by leveraging the natural reactivity of polysaccharides and the binding properties of residual lignin.