Abstract: With 1,3-Bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane (aminopropyl end capping agent) and octamethylcyclotetrasiloxane (D₄) as starting materials,aminopropyl end capped polydimethylsiloxane was synthesized under the catalysis of tetramethylammonium hydroxide ((CH₃)₄NOH) silanolate.The optimum conditions were obtained as follows:reaction temperature 80-90 ℃;reaction time 5 h;dosage of silanolate catalyst 0.75% (based on total mass of D₄).The relationship between the dosage of capping agent (W_f) and product viscosity (η₂₅) as well as actual amine equivalence of the product (W′_NH),and the relationship between the average molecular weight (M_w) and product viscosity were studied.Structure of the product was characterized by IR spectrum,and the result showed that the end capping agent reacted with D₄ successfully.

Key words: aminopropyl end capped polydimethylsiloxane, capping agent, synthesis, characterization