Slow‐release fertilizer behavior of polyvinyl alcohol (PVA)/urea/TiO₂ nanofiber membrane

Abstract

Nanofiber is a material used as a drug carrier matrix in drug release materials. Its morphology has high porosity and good flexibility, making it suitable for this purpose. The use of nanofiber as a carrier matrix in slow‐release fertilizer (SRF) material is expected to provide a solution for releasing fertilizer into the soil more measurably and efficiently In this study, PVA/Urea/TiO2 nanofibers were fabricated using the electrospinning method. PVA/Urea/TiO2 SRFs were prepared using varying urea mass percentages (10%, 15%, and 20% of PVA mass) and the concentration of titanium dioxide suspension solution (0, 0.2, and 0.4 mL). Every sample was analyzed using scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) and tested using contact angle and slow‐release tests. From SEM characterizations, all samples showed the ability to form nanofiber. It was found that the membrane diameter sizes for each sample A, B, C, D, E, and F were 341 ± 5, 309 ± 12, 109 ± 3, 313 ± 10, 109 ± 3, and 158 ± 6 nm, respectively. The FTIR characterizations showed that all the matrix samples successfully contained the nitrogen group, which was found at wave number 1605 cm−1 (NH deformation), 1574 cm−1 (CN stretching), and 3430 cm−1 (NH stretching). The SEM mapping images confirmed the presence of titanium dioxide (green dots). The contact angle test showed that all samples had hydrophilic properties (the contact angle value lower than 90°), and the greatest value of contact angle measurement was 31.08° for sample C/E (sample with the most presence of TiO2 suspension solution 0.4 mL). The sample with the greatest TiO2 suspension concentration (0.4 mL) had the longest urea release time, lasting 8 days. This result indicates the addition of TiO2, can potentially suppress the hydrophilic properties of the PVA membrane. It is found that the addition of TiO2 influenced the membrane's hydrophilicity, consequently increasing the release rate. This study used the Korsmeyer–Peppas mathematical kinetic model to show that diffusion and swelling are release mechanisms for SRF membranes.