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Silicone surfactants Spreading

In spite of its obvious practical importance, the spreading behavior of mixtures of silicone surfactants and hydrocarbon surfactants has not been systematically studied. Early... [Pg.193]

Silicone surfactants are specialty surfactants that are primarily used in applications that demand their unique properties. Most applications are based on some combination of their (a) low surface tension, (b) surface activity in nonaqueous media, (c) wetting or spreading, (d) low friction or tactile properties, (e) ability to deliver silicone in a water-soluble (or dispersible) form, (f) polymeric nature or (g) low toxicity. The major applications will be discussed briefly in following sections. [Pg.196]

Trisiloxane surfactants have been used as adjuvants in agriculture. They increase the foliar uptake of pesticides, due to reduction of surface tension and superspreading. A method for improving the performance of agricultural compositions under conditions of low humidity has been developed, by using silicone surfactants that reduce the surface tension to less than 30 mN/m in 0.10% (w/w) aqueous solution, without concomitant spreading of the spray solution [60]. [Pg.220]

The effect of a silicone surfactant on the burning behaviour of the polyurethane foam can be quite significant even though they normally represent less than 1 % of the plastic material. It is due to the fact that in any case the decomposition of a polyurethane foam starts at the surface. Because of the surface activity of the foam stabilisers it is easy to rationalise their enrichment on the surface and it is the surface that is the most influential part of the polymer regarding flame spread development. [Pg.96]

These surfactants can lower the surface tension of water to below 20 mN (most surfactants described above lower the surface tension of water to values above 20 mN m typically in the region of 25-27 mN m ). Fluorocarbon and silicone surfactants are sometimes referred to as superwetters as they cause enhanced wetting and spreading of their aqueous solution. However, they are much more expensive than conventional surfactants and are only applied for specific applications whereby the low surface tension is a desirable property. [Pg.15]

Even on micellar solutions of this compound, the PDMS oil forms lenses with zero spreading pressure. Similar behavior is seen with submicellar solutions even up to air-water surface tensions of 45 mN m. Since the oil spreads on water, this suggests a possible first-order wetting transition between partial wetting and pseudo-partial wetting at even higher air-water surface tensions. Rather surprisingly then, this means that no penetration of the monolayer of this silicone surfactant by the PDMS must occur. [Pg.104]

If S is positive (or zero) spreading is spontaneous. If S is negative (nonzero 0), spreading is limited. To achieve spontaneous spreading of spray droplets on leaf surfaces a zero contact angle is required and this is achieved in most case by the so-called superwetters such as fluorocarbon or silicone surfactants. [Pg.274]

Although silicone oils by themselves or hydrophobic particles (e.g., specially treated silica) are effective antifoams, combinations of silicone oils with hydrophobic silica particles are most effective and commonly used. The mechanism of film destruction has been studied with the use of surface and interfacial tensions, measurements, contact angles, oil-spreading rates, and globule-entering characteristics for PDMS-based antifoams in a variety of surfactant solutions.490 A very recent study of the effect of surfactant composition and structure on foam-control performance has been reported.380 The science and technology of silicone antifoams have recently been reviewed.491... [Pg.679]

Wagner, P., Wu, Y., van Berlepsch, H. and Perepelittchenko, L. (2000) Silicon-modified surfactants and wetting IV. Spreading behaviour of trisiloxane surfactants on energetically different solid surfaces. Appl. Organometallic Chem., 14(4), 177-88. [Pg.200]


See other pages where Silicone surfactants Spreading is mentioned: [Pg.467]    [Pg.468]    [Pg.679]    [Pg.694]    [Pg.238]    [Pg.659]    [Pg.673]    [Pg.517]    [Pg.186]    [Pg.193]    [Pg.193]    [Pg.197]    [Pg.199]    [Pg.199]    [Pg.22]    [Pg.553]    [Pg.1464]    [Pg.690]    [Pg.95]    [Pg.303]    [Pg.304]    [Pg.16]    [Pg.403]    [Pg.497]    [Pg.22]    [Pg.174]    [Pg.175]    [Pg.596]    [Pg.714]    [Pg.284]    [Pg.681]    [Pg.142]    [Pg.32]    [Pg.193]    [Pg.184]    [Pg.489]    [Pg.631]    [Pg.3343]    [Pg.689]   
See also in sourсe #XX -- [ Pg.192 ]




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Surfactants, silicone

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