A greener approach for controlled release of Fenvalerate insecticide from renewable polymer thymol-formaldehyde-based encapsulated formulation

The research work presented in this study deals with the preparation of biobased thymol-formaldehyde polymeric microcapsules for the encapsulation of Fenvalerate insecticide. Fenvalerate, a synthetic pyrethroid used in veterinary and agriculture, affects non-target species. Therefore, herein we report successful utilization of renewable source-based thymol-formaldehyde (TF) polymer to encapsulate Fenvalerate insecticide for the first time. The novel TF microcapsules were characterized by optical microscopy, scanning electron microscopy, thermogravimetric analysis, particle size analyzer, and Fourier transform infrared spectroscopy. The controlled release of prepared microcapsules was studied by ultraviolet spectrometry and gravimetric analysis. Additionally, the stability and release kinetics of TF microcapsules were examined at different temperatures and pH. The particle size distribution and shell thickness were 1.94 µm and 181 nm, respectively. The TF microcapsules released higher core at acidic pH and approximately 16% after 12 days at room temperature. Such exploration can take a lead for an environment-friendly capsule suspension formulation. Graphical Abstract