Preparation and characterization of lignin grafted layered double hydroxides for sustainable service of bitumen under ultraviolet light

Bitumen could emerge the degradation of performance under ultraviolet (UV) light easily, then the bituminous pavement would have to be repaired and even reconstructed for safety, causing environmental pollution and energy consumption. Therefore, it is crucial to raise bituminous anti-UV aging property so that the service life of bitumen could be increased memorably, which is beneficial to environmental protection and sustainable development. Lignin grafted layered double hydroxides (LG-g-LDHs) were prepared successfully through covalent bonding with diphenyl-methane-diisocyanate (MDI), and were characterized by Fourier transform infrared (FTIR) spectrometer, scanning electron microscopy (SEM) contact angle tester and ultraviolet and visible (UV–vis) spectroscopy. Then LG-g-LDHs were used for modifying bitumen, the effects on anti-UV aging properties were researched by physical properties, four components analysis, FTIR and dynamic shear rheometer (DSR) test. The results showed that LG-g-LDHs were prepared and represented a stable cross-linked structure, then they had a combined effect of chemically absorbing and physically reflecting UV light owing to the multi-layered and benzene ring structure. Due to the introduction of lignin, the compatibility between LDHs and bitumen could be improved. After aging, the properties including physical properties and rheological behaviors of bitumen decreased and colloidal stability declined. Compared with LDH, LG-g-LDHs represented better inhibitory action in performance deterioration and colloidal stability of bitumen, which indicated that LG-g-LDHs could strengthen bituminous anti-UV aging properties for sustainable service of bitumen. • LG-g-LDHs were prepared via covalent linking with MDI. • LG-g-LDHs had a combined effect of absorbing and reflecting UV light. • LG-g-LDHs could improve the UV aging resistance of bitumen. • The preparation of LG-g-LDHs broadened the applied field of lignin.