| Microcapsules are functional materials that form a core-shell form with a natural or synthetic polymer as a shell,encapsulating a solid,liquid or gas core.Polymeric semipermeable membrane can protect the contents of the membrane from the environmental conditions,but also control the exchange of material inside and outside the membrane,in the field of control-release has important application value.In this paper,starch-based polyelectrolyte microcapsules were prepared by using the interaction between the opposite charge polyelectrolytes as the main substrate,and the effect of different intracapsule structures on the sustained release behavior of the implants was studied.Specifically include the following:1、The electrostatic interaction between cationic starch and polyacrylic acid was used to prepare polyelectrolyte microcapsules which could be used to encapsulate 2,4-D emulsion.The effects of different preparation conditions on the microstructure of polyelectrolyte microcapsules were systematically studied.The effect of different slow release environments on the controlled release behavior of 2,4-D embedded in microcapsules was proposed,and the formation mechanism of polyelectrolyte microcapsules was proposed by electrostatic interaction.The results showed that the release rate of 2,4-D was the slowest when the pH value was 4,the temperature was 15 ℃ and the salt concentration was 1.5%(w / w).2、The water core of polyelectrolyte microcapsules was changed into gel nucleus by using carrageenan as gelling agent and ferric chloride as expansion inhibitor.At the same time,the mechanical strength of polyelectrolyte microcapsules was improved,and polyelectrolyte microcapsules to study the slow release properties of small molecular fertilizers-urea.The results showed that the microcapsules had the best sustained release properties of urea when the amount of carrageenan was 0.5g,the concentration of ferric chloride was 0.05 M and the crosslinking time was 30 min. |
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