Abstract:Dispersants containing lignosulfonale were commonly used in pesticides, but they failed to meet the requirements for nanoparticle pesticide dispersion. Lignin samples with varying molecular
weights and degrees of sulfonation were prepared through the process of sulfomethylationcombined with alkyl bridging. The influence of molecular weight and degree of sulfonation on their dispersion stability in nanopesticide suspensions was explored. The results indicated that, at the same dcgree of sulfonation, the dispersion stability of lignin dispersants was initially improved and then decreased with increasing molecular weight. To achieve the best dispersion effect, the sulfonation degree and molecular weight of lignin needed to be coordinated. As the sulfonation degree increased, the appropriate molecular weight should also increase accordingly.GCL4-Nano, with a sulfonation degree of 1.58 mmol/g and a molecular weight of 14 897 Da, was found to exhibit excellent dispersion stability for nanopesticides of different varieties.The nanopesticide suspensions prepared had an average particle size ranging from 165 nm to 206 nm,with a suspension rate exceeding 95%.Additionally,they demonstrated excellent wetting propertics,resistance to rainwater washing,and photostability.