the number of cells cm and the regularity of the cell structure obtained in addition the pressure build up which results in a circular feed line having a diameter of 2 cm on passing 8 liters per minute through the foam specimen was measured as a measure of the open cell content of the foams obtained the lower the measured pressure build up the more open celled the foam obtained the following results were obtained concentration concentration cell fineness pressure of bc 2555 of diluent cell no of cells build up pphp additive pphp structure per cm mm of water 0 38 none u2014 slightly 6 80 irregular 0 38 dipropylene 0 22 slightly 6 7 300 glycol irregular 0 38 propylene 0 22 regular 14 27 carbonate 0 38 ethylene 0 22 regular 12 34 carbonate 0 38 dimethyl 0 22 slightly 4 232 carbonate irregular 0 5 none u2014 regular 7 8 292 0 5 dipropylene 0 3 virtually 7 125 glycol regular 0 5 propylene 0 3 regular 14 35 carbonate 0 5 ethylene 0 3 regular 12 81 carbonate 0 5 dimethyl 0 3 regular 4 5 234 carbonate the data clearly demonstrate that the use of cyclic organic carbonates as component in flexible foam formulations or as component of a foam.