Synthesis of trifunctional graft polymer polyether polyols employing a silica based gel as non-aqueous dispersant

Currently, the PU industry is developing new products with enhanced physical, mechanical and structuralproperties. One of the specialties that is attracting more and more attention from managers and enterprises allover the world are the PUs based on polymer polyether polyols (graft polyols).In this work, the synthesis of graft polyols was developed employing a non-aqueous dispersant (NAD) basedon silica gel, which contains in its chemical structure segments with a great affinity for the solid polymericparticles and other segment having a strong affinity for the hydroxyl groups of the liquid polyol. The combi-nation of both polar and non-polar characteristics ensures the stability of the resulting polymer dispersion andprevent the sedimentation and the coalescence of the polymer particles. By using this NAD it was possible tosynthesize trifunctional polymer polyether polyol (PPP) from Styrene and containing up to 38.69 wt% of solids.The optimal reaction conditions have been stablished using a concentration of 1.5 wt% NAD, 4 wt% of initiatorrespect to the monomer amount and a polymerization temperature of 80 °C. The viscosity of the optimal PPP(1930 mPa·s) and the particle size (dv0.5of 5.427µm and dn0.5of 1.711µm) were in the range of graft polyolsavailable in the market for similar solids content, with the additional advantage of employing a lower quantity ofNAD and a softer reaction temperature than those employed in the industrial process (110 °C