Synergistically Reinforced Nanocomposite Leather Coatings: Multiphase Copolymer Systems Enhanced by Hydrotalcite Nanosheets and Aramid Nanofibers

A waterborne nanocomposite leather finishing system was developed through a two-step fabrication strategy. First, layered double hydroxide (LDH/hydrotalcite) nanosheets were electrostatically assembled onto aramid nanofibers (ANF) to construct a reinforced LDH@ANF heterostructure. Then, a multifunctional copolymer (H-P) was synthesized via surfactant-free emulsion polymerization using sodium p-styrene sulfonate (SSS) as both monomer and emulsifying agent. The integration of LDH@ANF as a nano-reinforcement phase into the H-P matrix yielded stable nanocomposite emulsions (LDH@ANF/H-P) with exceptional leather finishing capabilities. The nanocomposite coating simultaneously endowed sheepskin with superior abrasion resistance (COF: 0.13), hydrophobicity (contact angle: 108° ± 2.9°), thermal insulation (thermal conductivity: 0.073 W/m K) and flame retardancy. Compared to pure H-P film, the tensile strength and elongation at break of the LDH@ANF/H-P film increased by 5.32 MPa and 377.28%, respectively, attributed to the synergistic effects of LDH nanosheets and ANF. Moreover, the pure H-P exhibited 38% higher abrasion resistance than commercial NP-87 polymer, while the nanocomposite coating further reduced the surface abrasion by 68% through hierarchical energy dissipation mechanisms.