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No chemistry required (it would not hurt to know some)
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Some chemistry or physics required
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| Surfactant |
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Surfactants fulfill the function of stabilizing the foam
structure during foaming of a polyurethane foam. These surfactants are
capable of lowering the surface tension of the polyol and in addition they
are capable of stabilizing the foam structure. One important requirement for
a good surfactant is the formation of viscous surface layers. Silicone block
polymer offer for most applications the ideal surfactant properties.
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Silicone. Most of the silicone surfactants are either
methylsilane- ethylene oxide or propylene oxide block polymer. The end
groups on the polyether chain can be a reactive hydroxyl group or can be
capped with an alkoxy group. Polyethers capped with an alkoxy group
are not reactive with isocyanates and can be used also as a surfactant in
the isocyanate.
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Non-silicone. Block copolymer of butylene oxide
and propylene oxide are an example of non-silicone surfactants. Both end
groups can be blocked for use as surfactant with isocyanates .
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