Study on the key preparation process of beta-cypermethrin poly (N-propylacrylamide) temperature-sensitive microsphere

In order to develop a pesticide product for the control of Carposina niponensis Walsingham, beta-cypermethrin poly (N-propylacrylamide) (PNNPAM) temperature-sensitive microsphere was developed. Given that the volume phase transition of PNNPAM and the peak emergence of C. niponensis happen at similar temperature, the microsphere was prepared by a surfactant-free emulsion polymerization method. Effects of temperature, the concentration of N-propylacrylamide (NNPAM) and the concentration of N,N'-methylene diacrylamide (MBA) on the preparation of the microsphere were investigated. The results showed that, when the reaction temperature was 70-80℃, the particle size of the temperature-sensitive microsphere prepared was (601.3±5.6)-(638.6±8.9) nm, and the drug-loading and embedding rate of the microsphere were both relatively high. The drug-loading and embedding rate increased with the increase of the concentration of NNPAM and MBA. In addition, temperature had a significant influence on the cumulative release rate of microsphere.