Preparation of fluorocarbon polymer emulsion by the method of soap-free emulsion polymerization

Self-crosslinked fluorocarbon polymer emulsion with core-shell structure was prepared via soap-free emulsion polymerization when the conception of particle design and polymer morphology was adopted. The prepared process involves three steps. The first is the formation of oligomer, the second is the preparation of seeded emulsion, and the third is the preparation of fluorocarbon polymer emulsion with core-shell structure. Main factors, which had an influence on the polymerization technology and the performance of the product, were investigated and optimized. Results show that the optimal conditions for preparing fluorocarbon polymer emulsion are as follows: for preparing the oligomer, mol ratio of BA to MAA is equal to 1.0: 1.60, and pH value is controlled within the range of 8.0 and 9.0; the added amount of oligmer P (BA/MANa) is 6%; mass ratio of BA to MMA is 40:60; the added amount of self-crosslinked monomer is 2%, the added amount of hexafluorobutyl acrylate is 15%;reaction temperature is 80& deg;C;the mixture of potassium persulfate and sodium bisulfite is used as the initiator. The structure and performance of the fluorocarbon polymer emulsion were tested with FTIR, TEM, MFT and contact angle and water absorption of the latex film. The film-forming stability of the fluorocarbon polymer emulsion and the performance of the latex film, which is prepared with the soap-free emulsion polymerization, are better than the one prepared with the conventional emulsion polymerization.