A block silicone softener (ATSO-PDE) was synthesized by alkali method with amino-terminated polysiloxane (ATSO) and polypropylene glycol diglycidyl ether (PDE) as raw materials. The chemical structure of amino-terminated siloxane (ATS) was characterized by ¹H NMR, ¹³C NMR, and FTIR. The main factors affecting ATSO conversion rate and properties of product were investigated. The optimal ring opening reaction condition of ATSO was 110 ℃ for 2 h. The application of ATSO-PDE on cotton fabrics indicated that fabrics treated by softener with high ammonia value (0.70 mmol/g) expressed good softness while softener with low ammonia value (0.40 mmol/g) expressed good smoothness. The adsorption mechanism and orientation distribution of silicone softener on the fibers were analyzed by the establishment of the orientation distribution model. It was indicated that the different properties and surface morphology of ATSO-PDE were related to the molecular structure and the orientation on the surface of the fiber

Keywords: alkali method, softener, block silicone, film morphology, orientation