Development of Palm Oil-Based Poly(urethane Urea) Adhesives for Composite Waterproofing Membranes Reinforced with Waste Poly(ethylene Terephthalate) Fibers

Waterproofing membranes are widely used on roofs, walls, basements, and other parts of buildings to effectively prevent water penetration and erosion. This study develops a sustainable composite waterproofing membrane from a palm oil-based poly(urethane urea) (POPUU) elastomer and waste poly(ethylene terephthalate) (PET) fibers. A high biobased content POPUU elastomer was synthesized using renewable palm oil-based diethanolamide, 4,4′-diaminodiphenyl disulfide (APDS), and hexamethylene diisocyanate. The incorporation of APDS into the POPUU promoted a microphase-separated structure with abundant hydrogen bonds, significantly enhancing its adhesion and cohesion. The POPUU adhesives exhibited a lap-shear strength of up to 6.2 MPa on wood with good performance on steel and glass. The bonded samples maintained an average of 80% of their initial strength across multiple bonding cycles and a broad temperature range (−25–50 °C). The prepared PET fiber-reinforced composite membranes exhibited impressive tensile properties (442.9 N/50 mm, 59.1%), thermal aging resistance, peel strength, and water impermeability.