Inverse emulsions in a molten salt/hydroxy-terminated polybutadiene system using block copolymers as emulsifiers

• Published in: Journal of polymer science. Part A, Polymer chemistry Polymer chemistry, 1990-09, Vol.28 (10), p.2777-2792
• Main Authors: Litt, M. H., Lin, C. S., Krieger, I. M.
• Format: Article
• Language: English
• ISSN: 0887-624X; 1099-0518
• DOI: 10.1002/pola.1990.080281016

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.