Foamed polysiloxanes with properties

Chem. Descrip. Polysiloxane-polyether copolymer surfactant Uses Foam stabilizer for rigid PU foams, continuously laminated PU boardstock, modified polyisocyanurate foams, spray foams synergistic with flame retardants Properties Cl. vise, liq. sp.gr. 1.072 0.01 g/cc vise. 730 150 mPa-s f.p. < 10 C ... 

The formation of cellular products also requires surfactants to facilitate the formation of small bubbles necessary for a fine-cell structure. The most effective surfactants are polyoxyalkylene-polysiloxane copolymers. The length and ethylene oxide/PO (EO/PO) ratio of the pendant polyether chains determine the emulsification and stabilizing properties. In view of the complexity of the interaction of surfactant molecules with the growing polymer chains in foam production, it is essential to design optimal surfactants for each application. Flexible polyurethane foams require surfactants that promote improved cell-wall drainage. This allows the cell walls to become more open during the foaming reaction. Also, the shift away from TDI to MDI in molded HR foams adds new demands on foam surfactants (97). 

The convenient properties of liquid and solid dimethylpolysiloxanes (thermal and chemical stability, hydrophobicity, anti-adhesive behavior, etc.) make them suitable for a variety of technical applications in medicine. Especially pure preparations (Silastic ) have been used to construct artificial limbs, gullets, cardiac valves, trachea, etc., and in face-lifting. Silicon rubber breast implants, which are filled with a polysiloxane gel, have been used cosmetically. Synthetic arteries impregnated with silicon do not break or cause coagulation, they are flexible, and they are well tolerated immunologically. Silicones prevent the formation of foam in equipment for artificial blood circulation (heart-lung machines). The surfaces of such equipment, and of the... 

Chem. Descrip. Polysiloxane-polyether block copolymer Uses Foam stabilizer and emulsifier for rigid PU and polyisocyanurate foams with max. demand on flow properties esp. for refrigeration and pipe insulation Properties Cl, vise, liq, sol. in common rigid foam polyols and resin preblends dens. 1,055 0,01 g/cc vise. 750 170 mPa-s solid, pt. < -8 C hyd. no. 100 10 cloud pt. 70 3 C (4% aq.) pH 6.5 1.5 (4% aq.)... 

Pashinin, V. L, Kozlov,V. T., Tarasova, Z. N., Safonova, G. V. Kauch., Rezina (Russian), Correlation of structural characteristics with the properties of irradiated polysiloxane rubber foams, Kauch.Rezina, (10), 18-21(1981)... 

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