Research On Blending And Graft Modification Of Vae Emulsion

In this paper, the properties of VAE copolymer emulsion were modified by emulsion blend with a series of polyurethane(PU) emulsion or polyacrylate(PA) copolymer emulsion, which were synthesized by the theory of molecular and particle design, and by emulsion graft polymerization with various proportion and dosage of acrylate monomer, directed by the theory of macromolecule blend. The morphologies and structures of these blend or composite particles and their distributions had been studied by Transmission Election Microscope(TEM). The stability of the blend emulsions and composite emulsions and resistance to water and mechanical properties of the latex films had been determined and analyzed. Their compatibilities had been studied by Differential Scanning Calorimeter(DSC).The stabilities of the blending emulsions are affected by the electric charge and particle-size of the latex particle, emulsifier, PH value and so on. PH value is the decisive factor. The stabilities of the composite emulsions decrease while the dosage of monomer and n-butyl acrylate(BA) increase.The VAE and PU, PA particles in the blending emulsions had been well distributed. And these particles size were increased to some degree compared with the one before blending. Some particles of PU, PA emulsions were absorbed on the surface of VAE particle. The particle-size of composite emulsions had more increasing than blending emulsions.The properties of the blending latexes film were affected by the factors such as:the proportion of the soft and hard segment in PU molecule, the proportion of NCO and OH in PU system, Tg and polymerizing technology of PA system, the proportion of PU and PA emulsions in the blending system. Compared with VAE copolymer, VAEIPU and VAE/PU blending emulsions had high tensile strength for the latexes film and better adhesion to wood/wood and PVC/PVC. And VAEIPA blending system was the better. The factors affected the properties of the composite emulsions film were Tg of the monomer copolymer and the dosage of monomer.It shows that the blending system were partial compatible. It got better effect of modification after improving the compatible of VAE and PA by the molecular and particle design. The compatible of VAE and PA in the composite emulsions is better than the blending system.