The effect of grafted poly(ethylene glycol monomethyl ether) on particle size and viscosity of aqueous polyurethane dispersions

Aqueous dispersions of nonionic grafted polyurethane (PU) were prepared by reaction of polytetrahydrofuran (PTHF), toluene diisocyanate (TDI) and 1,4-butane diol (BDO). Then N-substituted with poly(ethylene glycol monomethyl ether) (PEGMME) pendant group by generation of active anion sites on the polymer back bone, followed by treating with corresponding chlorinated PEGMME. The prepared polymers were analyzed by contact angle measurement, Fourier transform infrared (FT-IR) and H NMR spectroscopy and the effect of various molecular weight of PEGMME on particle size and viscosity were studied. Particle size decreased and emulsion Viscosity increased with increase in PEGMME molecular weight. The decrease in particle size and increase in viscosity are due to increased chain flexibility and or hydrophilicity of grafted PU.