Experimental Study On The Liquid-Driven Coaxial Flow Focusing For Preparation Of Pesticide Microcapsules

As a new pesticide formulation,the microencapsulation of pesticides can reduce the toxicity of pesticides to animals and plants in nature and prevent the rapid degradation of pesticides in the natural environment.We propose a new method to prepare pesticide microcapsules by the liquid-driven coaxial flow focusing(LDCFF)process.The specific process is that the fluids flowing from the coaxial needle are focused under the action of the driving fluid to form a stable coaxial cone.The tip of the cone is ejected from the orifice and eventually collapsed into a uniform microcapsule due to propagation and amplification of instability perturbations during the subsequent movement.Compared to other pesticide microencapsulation methods,the liquid-driven coaxial flow focusing process proposed in this paper has the advantages of easy operation,stable technology,high encapsulation efficiency,high yield,high consistency of microcapsule size,and strong resistance to environmental disturbances.All of the advantages show that the liquid-driven coaxial flow focusing process can achieve large-scale mass production of pesticide microcapsules in industry.The specific content are as follows:(1)We propose the liquid-driven coaxial flow focusing process to fabricate pesticide microcapsules.And we have designed and manufactured the nucleus devices including stainless steel coaxial needles,drive chambers,etc.Besides,a complete experimental platform including a fluid supply device,a microcapsule production device,an observation device,and a data acquisition device is developed.We choose poly(lactic-co-glycolic acid)(PLGA),a naturally degradable polymer material,as shell material to prepare pesticide microcapsules.(2)We have systematically studied the process control of preparation of pyraclostrobin loaded microcapsules by the liquid-driven coaxial flow focusing process,including the morphology characteristics,particle size control,drug sustained-release properties of pesticide microcapsules,which can provide the theory guidance to the production of pesticide microcapsule.(3)We have explored the integrated process of industrial application of the liquid-driven coaxial flow focusing process.And we propose a liquid supply system,a microcapsule production system,and a microcapsule separation and collection system for industrial production.This provides a feasible solution for the technology to achieve industrial production.