Fabrication of a Temperature-Controlled-Release Herbicide Using a Nanocomposite

In this work, temperature-responsive controlled-release herbicide particles (TCHP) with a core shell structure were developed using a nanocomposite consisting of attapulgite (ATP), NH4HCO3, amino silicon oil (ASO), poly(vinyl alcohol) (PVA), and glyphosate (Gly). Therein, the ATP-NH4HCO3-Gly mixture acts as the core, and ASOPVA acts as the shell. ATP possesses a porous micro/nano networks structure and thus can bind a large amount of Gly molecules. NH4FICO3, as a foaming agent, can produce CO2 and NH3 bubbles to make plenty of micro/nano pores in the ASO-PVA shell, which facilitates the release of Gly. The pore amount can be efficiently adjusted by temperature, meanwhile the PVA shell tends to dissolve in aqueous solution at a high temperature, so that the release of Gly can be easily controlled. Importantly, this technology could effectively decrease the loss of Gly under simulated rainfall and thus improve the control efficiency on weeds. The hydrophobic ASO endows TCHP a high stability in aqueous solution for at least three months. This work provides a promising approach to control the release and loss of pesticide, which has a potential application to enhance the utilization efficiency and thus lower the environmental pollution.