Effects of altered reaction conditions on the synthesis of polyurethane-poly(2,2,2-trifluoroethyl methacrylate) triblock copolymer aqueous dispersion

Polyurethane-poly(2,2,2-trifluoroethyl methacrylate) (PU-PTFEMA) triblock copolymer aqueous dispersions were synthesized by three-step polymerization. In the first step, polyurethane prepolymers (PU) based on 2,4-toluene diisocyanate (TDI), polyether binary alcohol (N-220), alpha,alpha-dimethylol propionic acid (DMPA), hydroxypropyl acrylic acid (HPA), and butanediol (BDO) were prepared with butanediol as the chain extender and methylethylketon as solvent. The next step involved neutralization and dispersion in water, where prepolymers were neutralised by the addition of triethylamine (TEA). The last step was the seeded emulsion polymerization, where PU emulsion was used as seed, kalium persulfate (KPS) as initiator and 2,2,2-trifluoroethyl methacrylate (TFEMA) as comonomer. Factors influencing the synthesis of PU-PTFEMA copolymer aqueous dispersion were studied. Experimental data indicate that factors influencing the synthesis of PU-PTFEMA copolymer aqueous dispersion mainly involve reaction temperature, reaction time, the concentration of initiator, DMPA content, TFEMA content. Rotational viscometer and dynamic light scattering (DLS) were used to characterize the properties of copolymer aqueous dispersion. (C) 2007 Elsevier Ltd. All rights reserved.