PLA/starch biodegradable fibers obtained by the electrospinning method for micronutrient mineral release

Developments in nanofibers seek to increasingly expand the field of support and release of actives, such as fertilizers. Using nanofibers as materials for mineral nutrients aims to increase the efficiency of contact release of the fertilizer to the plant root in the soil. Poly lactic acid (PLA) is a polymer with biocompatibility characteristics and spinning conditions. The starch biopolymer combined with PLA can improve the biodegradation properties and hydrophilicity of the fibers and allow the solubilization of the fertilizer source for the plant. Thus, the present paper sought to find a polymeric matrix in the form of PLA/starch nanofibers that could act in the release of the mineral micronutrient manganese as a model asset. The electrospinning method was employed to obtain the fibers varying the starch concentration from 10 to 50% (w/w) in the polymeric matrix. The nanocomposite containing manganese carbonate as a source of Mn²⁺ ions was produced from the best membrane composition. The results showed that the analyzed PLA/starch blends with 20% (w/w) provided better fiber affinity with water, which is fundamental for fiber degradation time. Regarding fertilizer release, the starch present in the PLA fiber at a concentration of 20% (m/m) promoted better control in the release of Mn²⁺. The total release occurred after 5 d in contact with the 2% citric acid extractive medium. Thus, PLA/starch fiber becomes an alternative in the packaging of particulate fertilizers, providing increased contact area during root application with gradual delivery of mineral nutrients and minimizing loss by leaching.