Rosin-Based Poly(urethane-urea) with Excellent Self-Healing Ability and UV Shielding

With global ozone layer depletion, developing sustainable ultraviolet (UV)-shielding materials with high environmental persistence has emerged as a critical challenge. Conventional UV-shielding agents face limitations in biodegradability and durability. In contrast, rosin, a natural biomass featuring hydrogenated phenanthrene rings and π-conjugated systems, exhibits exceptional UV absorption (200–400 nm). In this study, we synergistically integrated dynamic hindered urea bonds (HUBs) with rosin-derived motifs to construct multifunctional rosin-based poly(urethane-urea) networks. Four diisocyanate-derived prepolymers were synthesized and subsequently copolymerized with rosin derivatives via UV curing. The isocyanate architectures were found to govern hydrogen-bonding density, mechanical adaptability (tensile strength: 3.9–16.4 MPa; toughness: 8–19.9 MJ·m–3), and self-healing performance (88.6% within 24 h at 60 °C). The optimized material achieved 95% UV-A and 100% UV-B shielding efficiencies while maintaining chemical stability (acid, alkali, and high temperature environments). Reversible HUBs further enable recyclability and programmable shape-memory behavior. These features highlight the material’s potential for advanced applications such as smart protective coatings and flexible electronic encapsulation.