Preparation of fluorinated polysiloxane and its application in modified polyacrylates

Polyacrylate materials are widely used in textile adhesives, functional finishing agents, architectural coatings, and other fields. In order to improve their hydrophobicity and flexibility, a novel fluorinated polysiloxane was prepared by acid catalyzed bulk ring opening reaction with octamethylcyclotetrasiloxane (D4), tetramethyltetravinylcyclotetrasiloxane (D4v), and methyltrifluoropropylcyclotrisiloxane (D3F), and its structure was characterized. Then, as a modified monomer, the fluorinated polysiloxane modified polyacrylates was prepared by miniemulsion polymerization. The effects of fluorinated polysiloxane monomers with different vinyl content and molecular weight on the properties of emulsion, film structure and film hydrophobicity were studied. The results showed that when using fluorinated polysiloxane monomer with Mn = 6235, vinyl content of 0.33 mmol/g, and fluorine content of 7.40 mmol/g for modification, the water contact angle on the surface of the adhesive film reached 100.4°, and the water absorption rate was 8.1%, resulting in the best effect. Used for textile printing, the color fastness to dry and wet friction after fabric printing could reach level 4, and the hand feel was soft. We have prepared two modifiers, namely, fluorinated polyvinylpolysiloxane and vinyl terminated fluorinated polysiloxane, and carried out miniemulsion polymerization with acrylate monomers to prepare the fluorinated polysiloxane modified polyacrylates. It was found that the vinyl terminated fluorinated polysiloxane can better migrate to the surface of the film, resulting in better hydrophobicity and mechanical properties of the adhesive film. Fluorinated polyvinylpolysiloxane, due to more double bond crosslinking, remains in the film matrix and has limited improvement in the hydrophobicity and mechanical properties of the film.