High blades spreadability of chlorpyrifos microcapsules prepared with polysiloxane sodium carboxylate/sodium carboxymethylcellulose/gelatin via complex coacervation

摘要

The sustainable-release property and spreadability of microencapsulated pesticide on blades have attracted special interest mainly because they are related to the utilization of pesticide. In this work, polysiloxane sodium carboxylate (PSiSC) surfactant with double hydrophobic chains has been introduced for the first time into the capsule shell materials to improve the spreadability of the chlorpyrifos microcapsules on rice blades. The silicone chlorpyrifos microcapsules have been prepared with PSiSC/gelatin (GE)/sodium carboxymethylcellulose (NaCMC) by complex coacervation method. Optical microscopy, scanning electron microscopy, laser particle size analyzer, fourier-transform infrared, energy dispersive X-ray spectroscopy, contact angle measurement and UV/VIS spectrometer are used to characterize the silicone chlorpyrifos microcapsules. The PSiSC/NaCMC/GE microcapsules that exhibit the chlorpyrifos encapsulation rate of 50.8%, surface smooth, the mean diameter around 3.5 mu m and shell thickness of 285 nm, fabricated with 1.2 mmol/L PSiSC surfactant at pH 4.6. The chlorpyrifos-loaded microcapsules are of remarkable sustainable-release property. The PSiSC/NaCMC/GE microcapsules own high spreadability on the rice blades, which promotes increasing the residual amount of chlorpyrifos microcapsules on hydrophobic blades, thereby improving the utilization of chlorpyrifos.