The application of coating materials to regulate nitrogen release is a crucial strategy for minimizing fertilizer loss and alleviating agricultural nitrogen pollution. However, it remains a significant challenge to develop ecofriendly coatings that are both biodegradable and effective in slow-release. In this study, Ca/Al layered double hydroxides (LDHs) were incorporated into a conventional polyvinyl alcohol/polyvinylpyrrolidone (PVA/ PVP) matrix to create PVA/PVP-LDHs composite films. The inclusion of LDHs (1.0 %, w/w) resulted in a 32 % enhancement in water resistance, a 10 % reduction in water vapor/ammonia permeability, and a 16 % improvement in mechanical properties. These enhanced performances by addition of LDHs were attributed to the combined effects of the tortuous diffusion pathways, and the formation of robust hydrogen bonding networks between the hydroxyl groups of LDHs and PVA/PVP at the organic-inorganic interface. These interactions could reduce free hydroxyl groups on the film surface, leading to hydrophobicity and structural integrity. The composite films exhibited significantly reduced nitrogen permeability under various pH conditions, indicating the improved stability in both acidic and alkaline soil environments. Degradation experiments revealed that the composite film lost 40 % of its mass over 120 days, with a half-life only 8.0 % longer than pure PVA/PVP. These results indicated that the incorporation of LDHs had minimal impact on biodegradability, maintaining the environmental compatibility of the films. These findings highlight the potential of PVA/PVP-LDHs composite films as sustainable, eco-friendly, and efficient slow-release fertilizer coatings, offering a practical solution for improving nitrogen use efficiency and reducing agricultural nitrogen pollution.

来源平台：CHEMICAL ENGINEERING SCIENCE