Polydopamine coating grown on the surface of fluorinated polymer to enhance the self-lubricating properties of lignin-cellulose based composites

In this paper, a novel ethanol-water Tris buffer system was developed to construct a polydopamine (PDA) protective layer on the surface of polytetrafluoro-wax (PFW) to obtain PFW@PDA with excellent hydrophilicity. The wood-based slurry was obtained by solvent encapsulation and lignin-cellulose assisted ball milling process using waste poplar powder and flake graphite as raw materials. PFW@PDA exhibited excellent dispersion stability in such aqueous slurry and the water was removed from the slurry by vacuum filtration to obtain paperbased composite films. Based on the self-reinforcement of the lignin-cellulose cross-linked network, construction of graphene thermal conductivity network, and the effectiveness of PFW@PDA for wear reduction and selflubricating. This composite film exhibits excellent water resistance, good thermal stability, and superior mechanical properties. The friction coefficient and wear rate were reduced by 71.3 % and 166.7 %, respectively, compared with the unmodified material. Besides, the end-of-life products can be recycled by mechanical crushing in water, which exhibits a good balance between wear resistance and sustainability, providing a new idea for improving the hydrophilicity of fluorinated polymers and enhancing paper-based friction materials.

Automated summary

A novel ethanol-water Tris buffer system was developed to fabricate a hydrophilic polydopamine (PDA) protective layer on the surface of polytetrafluoro-wax (PFW). The resulting PFW@PDA displayed excellent dispersion stability in an aqueous slurry, and paper-based composite films were obtained by removing water from the slurry. The composite film exhibited excellent water resistance, thermal stability, and mechanical properties with reduced friction coefficient and wear rate.