Effect of Silicone Surfactant on Air Flow of Flexible Polyurethane Foams

Grafted copolymers which consist of a polydimethylsiloxane backbone and poly(ethylene oxide-co-propylene oxide) pendant groups are used as surfactant to stablize the bubbles in flexible polyurethane foam. The final properties such as air flow through the foam are significantly affected by the structure of the silicone surfactant used. Foams in which only the surfactant was changed provide a relationship between surfactant structure and foam air flow. Air flow of the foam increased as the polysiloxane backbone length of the surfactant decreased. Air flow of the foam increased as the polyether branch frequency of the surfactant increased. The drainage rate of cell windows and the foam top skin breaking time are shown to have significant effect on percentage of open cell windows. Both cell window drainage rate and top skin blow-off time are affected by silicone surfactant structure. Basic surface chemistry measurements such as surface tension, dynamic surface tension and dynamic light scattering method are used to characterize the surfactant properties.