| 摘要 |
Linear alkyl amine polyethoxylated containing in the alkyl chain 16 to 20 carbon atoms are worldwide used as surfactants for pesticides. Concerns on the negative effects on environment and health of these surfactants forced the search to new surfactants. Branched alkyl alcohols polyethoxylated or polypropoxylated as well as branched alkyl amines polyethoxylated or polypropoxylated with alkyl chains with 10-12 carbon atoms present a much lower surface tension than linear alkylamines polyethoxylated or polypropoxylated. The reason for the lower surface tension in water solutions is the steric hindrance of micelles formation caused by the branches. Micelles consisting of surfactant molecules reduce the amount of surfactant available to deposit in the interphase where they decrease the surface tension. The reason for the lower toxicity of the branched alkyl alcohol polyethoxylated or polypropoxylated as compared to linear or branched alkyl amines polyethoxylated or polypropoxylated, measured in algal growth inhibition, daphnia tests, eye irritation tests in rabbits and endocrine disruption tests, is the absence of the amine function. However, branched alkyl alcohols polyethoxylated or polypropoxylated have a limited solubility as compared to linear alkylamines polyethoxylated used before. We found that the addition of an additive to the formulation increasing the lipophilic character creates a compromise between the hydrophilic characteristics of the formulation to solve ionic or strong polar components of the formulation and the lipophilic characteristics to solve the branched alkyl alcohol polyethoxylated or polypropoxylated. There surfactants are therefore environmental friendly in the case of their application for pesticides, because they reduce the amount of pesticides per hectar and the toxicity of the spray formulation itself. |
