Synthesis of nonylphenol polyoxyethylene oligomer and application as an effective dispersant in pyraclostrobin suspension concentrate

A versatile dispersant plays a critical role in suspension stability of pesticide aqueous suspension concentrate (SC), thus it is extremely important to design and synthesize an effective dispersant for SC. Herein, nonionic trimeric nonylphenol polyoxyethylene (10) (TNP10) was successfully synthesized using nonylphenol polyoxyethylene(10) ethers (NP10) as raw materials. The surface activities of TNP10 were evaluated according to critical micelle concentration (CMC), and the surface tension at CMC (γCMC). TNP10 showed higher surface activity due to its lower CMC value compared with that of NP10. In addition, the dispersing and stabilizing properties of TNP10 in 25 wt.% pyraclostrobin SC system were investigated. The results showed that TNP10 as a dispersant exhibited more excellent dispersion performance than NP10. Meanwhile, the obtained SC system exhibits shear thinning behavior under high-speed shearing showing typical features of pseudo-plastic non-Newtonian fluids, which conforms to the Herschel-Buckley model. The nonionic trimeric nonylphenol polyoxyethylene (10 can effectively improve the surface activities and the suspension rate and stability of SC compared with its monomer NP10.