Lignin-polyurea microcapsules with anti-photolysis and sustained-release performances synthesized via pickering emulsion template

In this paper, lignin-polyurea microcapsules (LPMC) with anti-photolysis and sustained-release performance were synthesized by interfacial polymerization based on Pickering emulsion templates of lignin particle-stabilized oil-in-water (O/W). Scanning electron microscopy (SEM) and optical microscopy (OM) images showed that LPMC was spherical in shape, with a double layer structure of a loose outer layer and a dense inner layer and its mean diameter was 10-100 μm. Fourier transform infrared spectroscopy (FTIR) indicated that lignin had successfully participated in the interfacial polymerization of polyurea. LPMC were used to encapsulate avermectin (AVM), a kind of photosensitive pesticide. According to the experiment results of sustained release and anti-photolysis performance, the AVM cumulative release amount of AVM@lignin-polyurea microcapsules (AVM@LPMC) was 85% more than that of AVM@polyurea microcapsules (AVM@PMC) 50% after 72 h. And the effective AVM retention rate of AVM@LPMC reached as high as 72%, while that of AVM@PMC was only 30% under UV radiation for 120 h.