Preparation of microcapsule suspension of herbicide oxyfluorfen polyurea and its effects on phytotoxicity on rice crop

Abstract

Herbicides based formulations are conventionally used as wettable powder or as Emulsifiable concentrate. The Emulsifiable Concentrates (EC) are prepared by mixing the active content with solvents and surfactants. However, these formulations have undesirable phytotoxic effects due to hazardous solvent and are unsafe to operators during application. Thus, capsule suspension (CS) formulation is considered as an alternative to EC formulations. In this study, we report the preparation of CS formulation of herbicide oxyfluorfen by polymerizing Methylene diphenyldiisocyanate (MDI) and Ethylenediamine (EDA). Water suspensions of the oxyfluorfen microcapsules were prepared by adding anionic, nonionic, polymeric surfactants and formulation auxiliaries. The study also aimed to determine the effect of surfactant on the stability of the microcapsule suspension. It was found that the nature of surfactant influenced the properties of the formulation. The synthesized microcapsules were characterized by Scanning electron microscope (SEM), Fourier Transform Infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The microcapsule suspensions were applied on rice crop to establish the safety and its future use instead of oxyfluorfen EC.

Graphical Abstract

Keywords:

• Polyurea
• microcapsules
• stability study
• dispersant
• release study

Acknowledgements

The authors thank Dr. Avinash for the assisting the research work and Mr. Ranganatha, Prabhakar for helping in conducting the phytotoxicity trials in fields.