FOAMABILITY OF PEO-PPO-PEO TRIBLOCK COPOLYMERS (P85 AND F108) AND ROLE OF THE FOAM FILMS

ABSTRACT

The foamability of two commercial PEO-PPO-PEO triblock copolymers (Synperonic P85 and F108, ICI) was studied and compared to the properties of single foam films. The volume of a steady-state foam column created with a combined pneumatic-mechanical device is used as a measure of the copolymers foamability. Experiments were carried out at bulk copolymer concentrations corresponding to full surface coverage, i.e. constant area per molecule, under equilibrium conditions. The foamability of F108 solutions was higher than that of P85 although the surface activity of both copolymers was similar. The foam volume increases with increasing the bulk copolymer concentration. Higher electrolyte concentration or lower pH caused the foam volume to diminish. A pronounced parallelism between the properties of dynamic foams and single microscopic foam films was observed: when thicker single foam films were formed (from F108 solutions) the steady

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R. Sedev

Present Address: lwan-N.-Stranski-Institut für Physikalische und Theoretische Chemie, Technische Universitat Berlin, Ernst-Reuter-Haus, StraBe des 17. Juni 112, D-10623 Berlin, Germany, E-mail: [email protected]