Abstract: In this paper, the influence of a double comb-shaped copolymer (AgrilanTM 752) on dispersion stability of imidacloprid suspension was studied with FTIR, SEM, XPS, zeta potential and particle size tests. Agrilan^TM 752, which contained carboxyl groups, ester groups and poly-oxyethylene chain, combined with imidacloprid by hydrogen bond, van der Waals force and hydrophobic interaction, and dispersed imidacloprid particles in suspensions effectively. The experimental data indicated that thickness of Agrilan^TM 752 adsorbed layers, zeta potential and dispersion stability of suspension reached maximum values when its content was 3%(mass), i.e., the optimum Agrilan^TM 752 content under this experimental conditions was 3%(mass). Thickness of Agrilan^TM 752 adsorbed layers decreased at initial pH > 6, zeta potential had a maximum value at initial pH = 10. On the other hand, dispersion stability was good at initial pH from 2 to 10, and became worse with increasing initial pH value. Moreover, experimental results suggested that electrolyte ions, such as Na⁺, Mg²⁺ and Ca²⁺ reduced thickness of Agrilan^TM 752 adsorbed layers and zeta potential, and decreased the dispersion stability of imidacloprid suspension. Moreover, the ability of decreasing dispersion stability of imidacloprid suspension was Ca²⁺ > Mg²⁺ > Na⁺ at the same concentration.

Key words: dispersion, imidacloprid, suspensions, stability, double comb-shaped copolymer

摘要： 通过FTIR、SEM、XPS、zeta电位和粒度测试研究了双梳型共聚物Agrilan^TM 752对吡虫啉悬浮剂分散稳定性的影响。结果表明Agrilan^TM 752分子中存在羧基、酯基和聚氧乙烯醚侧链，通过氢键、范德华力和疏水作用力结合吡虫啉，从而有效地分散吡虫啉颗粒；Agrilan^TM 752用量与悬浮剂的分散稳定性密切相关，实验条件下得出其最佳用量为3%（质量分数），此用量下Agrilan^TM 752的吸附层厚度和zeta电位负值最大；初始pH值超过6后Agrilan^TM 752的吸附层厚度逐渐降低，zeta电位在初始pH = 10处存在最大负值，初始pH值在2～10范围内悬浮hina剂的分散稳定性普遍较高，pH值超过10后分散稳定性明显降低；电解质离子（Na⁺、Mg²⁺和Ca²⁺）浓度越高则Agrilan^TM 752的吸附层厚度和zeta电位负值越低，悬浮剂的分散稳定性越差，相同浓度下电解质离子对悬浮剂的分散稳定性影响程度顺序为Ca²⁺ > Mg²⁺ > Na⁺。

关键词: 分散, 吡虫啉, 悬浮系, 稳定性, 双梳型共聚物