Using a simple coating strategy to evolve polylactic acid into sand-fixation material with nutrient-rich reservoir by strong H-bonding interaction at phase interface

Developing simple and eco-friendly methods for polylactic acid (PLA) modification and establishing strong interfacial interactions between phases are still worthwhile research topics. Only by enabling sand barriers to continuously provide water and fertilizer for sand-fixing plants can effective control of desertification be truly achieved. Herein, a simple and eco-friendly coating functional modification strategy for PLA was introduced, involving in-situ curing of urea-aldehyde (UF)/polyacrylic acid (PAA) prepolymer after coating on PLA and then continuous rolling. During the preparation process, –NH in the amide group and –OH in the carboxyl group of UF/PAA form strong intermolecular H-bonding with C = O of PLA, resulting in high interfacial bonding strength and significant improvement in mechanical and hydrophilic properties of the modified PLA mesh. Wind erosion resistance, water absorption and holding capacity, nutrient content, and plant growth of the treated sand all display a very positive response. Effective surface coating modification evolves PLA into a “nutrient-rich reservoir” for sand-fixing plants without affecting its performances, thus truly achieving the desired but never achieved effective combination of natural sand fixation and mechanical sand barrier fixation, exhibiting great significance for further improving application performances and expanding applying fields of PLA through surface functional modification that is easy to industrialize.