Abstract: | Block copolymers of poly(N-t-butylbenzoyl ethylenimine) and poly(N-propionyl ethylenimine) (Bx/Ey and Bx/Ey/Bx) or poly (N-lauroyl ethylenimine) and poly (N-propionyl ethylenimine) (Ux/Ey) were synthesized by cationic ring-opening polymerization of 2-substituted δ2-oxazolines. Inverse emulsions (salt-in-oil) were made using these block copolymers as emulsifiers, hydroxy-terminated polybutadiene (HTPB) as the nonpolar phase and methyl ammonium ethane sulfonate (MAES) as the polar phase. These inverse emulsions (S/O) were then cured using a triisocyanate to give a dispersion of molten salt (MAES) droplets in polyurethane. Pore sizes of these cured inverse emulsions were measured from scanning electron photomicrographs as a function of stirring time and concentrations of block copolymer and molten salt. The results indicate that pores with diameters in the range of 1.5 X 10?6 m can be obtained using triblock copolymer Bx/Ey/Bx, and that the surfactant molecules can be spread as a monolayer at the MAES-HTPB interface. |