Abstract A new type of water-retaining, slow-release fertilizer (WSF) based on double-network hydrogels was fabricated via the ion-crosslinking of sodium carboxymethyl cellulose and the free radical polymerization of polymerizable β-cyclodextrin (MAH-CD), polyethylene glycol dimethacrylate (PEGDA), acrylamide (AM), and acrylic acid (AA) with urea-loaded halloysite as an additive. The effects of the AM to AA monomer ratio, the halloysite content, the AlCl3 content and the MAH-CD content on the swelling ratio were studied. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA) were applied to characterize the structure and properties of the WSF. The swelling behavior and water retention capacity of the fertilizer were investigated using a classic gravimetric method. The experimental results indicated that the presence of halloysite nanotubes clearly adjusted the swelling and release properties of the WSF. Kinetic modeling indicated that the swelling mechanism and slow release behavior were consistent with a Fickian diffusion mechanism. Form the considerations of its properties and raw materials, the fertilizer developed here has a good prospect of application and extension.

中文翻译：

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通过离子交联和自由基聚合制备基于纳米复合双网络水凝胶的保水缓释肥料

摘要 通过羧甲基纤维素钠的离子交联和可聚合β-环糊精（MAH-CD）、聚乙烯的自由基聚合，制备了一种基于双网络水凝胶的新型保水缓释肥料（WSF）。乙二醇二甲基丙烯酸酯 (PEGDA)、丙烯酰胺 (AM) 和丙烯酸 (AA)，并以负载尿素的埃洛石为添加剂。研究了AM与AA单体比、埃洛石含量、AlCl3含量和MAH-CD含量对溶胀率的影响。傅里叶变换红外光谱 (FTIR)、扫描电子显微镜 (SEM) 和热重分析 (TGA) 用于表征 WSF 的结构和性能。使用经典的重量法研究了肥料的溶胀行为和保水能力。实验结果表明，埃洛石纳米管的存在明显调节了 WSF 的溶胀和释放性能。动力学模型表明溶胀机制和缓释行为与 Fickian 扩散机制一致。在这里开发的肥料，从其性质和原料方面考虑，具有良好的应用推广前景。