Preparation of degradable poly(propylene carbonate)-chlorpyrifos micocapsule and performance evaluation on its controlled release

Degradable microcapsules of chlorpyrifos were prepared by emulsion solvent volatilization method using poly(propylene carbonate)(PPC) as wall material and polyvinyl alcohol-1788(PVA-1788) as emulsifier.The effects of PVA-1788 concentration,PPC concentration and mass ratio of PPC and chlorpyrifos on the performance of microcapsules were investigated.The degradation performance of PPC was evaluated by simulated soil suspension environment experiment.The PPC-chlorpyrifos microcapsule was charactered by scanning electron microscope (SEM),optical microscope (OM),wide-angle X-ray diffraction spectra(W-XRD) and high performance liquid chromatograph(HPLC),and performance of its controlled-release was studied by column chromatography.The results showed that PPC had a favorable biodegradation and all of the concentration of PVA-1788 and PPC and mass ratio of PPC and chlorpyrifos showed a significant effect on performance of chlorpyrifos microcapsules.When PVA-1788 quality score was 1.0%,PPC concentration was 110 mg/mL,mass ratio of PPC and chlorpyrifos was 1∶2,microcapsule with regular sphere and higher entrapment efficiency and drug-loading rate could be obtained.Under these conditions,average diameter of chlorpyrifos microcapsule was 7.3 μm,drug-loading rate and entrapment efficiency were respectively 16.75% and 89.34%.The results also showed that PPC microcapsule had a significant effect on controlled-release and the accumulated drug release reached 86.87% in 27 days.