Control of the Pore Structure of PLA Covering Film and Its Effect on Pesticide Release at Different Temperatures
The spraying of pesticides not only causes the waste of chemicals but also air pollution. To make the use of pesticides become more environmentally friendly and effective, biodegradable material polylactic acid (PLA) was chosen to package pesticides in this work. Three different film preparation methods (drying, coagulation bath shaping, and steam treatment) were used to study the morphology of PLA coated films. From FESEM images, it could be observed that the steam treatment was more easy in forming pore structures of the films. The sustained release performances of PLA film with the pore size around 800 nm for tetracycline hydrochloride (TC) and hymexazol (HYM) were investigated. The results showed that both chemical temperature and solubility could affect the sustained release effect of films. Due to the slower dissolution rate of TC compared to HYM, it was prone to aggregation in PLA films, which affected the sustained release of TC. The release rates of TC and HYM could reach 98.2% (40 °C, 2.5 h) and 99.51% (60 °C, 3.0 h), respectively. The release processes of TC and HYM conformed to the first-order kinetic model. It promotes the application of environmental friendly materials in pest control of plants.
危险品化学品经营许可证（带存储）