Block Copolymer Nonionic Surfactants

Table 2.3 Structure and Commercial Denomination of the Block Copolymer Nonionic Surfactants of the Pluronic Series ...

Figure 5.2.4 shows a network surface structure of a VA/AA-based emulsion with 6.6 wt% soiids. The repeat unit in the network structure is between 5 and 10 jtm. The formation of the network or bicontinuous surfactant structure is well established in relatively high molecular weight ethylene oxide/propylene oxide segmented block copolymer nonionic surfactants, and it has been ascribed to the formation of liquid crystalline macromolecular assemblies. Upon dilution, the emulsion showed 5-10 ttm spherical domains that could form aggregates up to about 60p.m in size (Fig. 4.4.5). In Fig. 5.2.5, bubble surfaces are shown with the network surfactant structure, even in the diluted emulsion. Apparently, the surfactant macromolecules tend to concentrate on bubble surfaces and form a more viscous and probably elastic polymer surface layer. 

EO and PO block copolymers, nonionic surfactants with molecular weight of 8000 amu, that is, Pluronics and Proxanols, are good emulsifiers for fluorocarbons. However, their effectiveness varies for different types of fluorinated organic liquids [55-58]. 

Nace VM (ed) (1996) Nonionic surfactants polyoxyalkylene block copolymers. In Surfactant science series, vol 60. Marcel Dekker, New York... 

It must be noted that another class of surfactants, very similar to the above, does not derive from alcohols but directly from combining PPG and PEG chains such surfactants are called EO/PO block copolymer nonionics (see Sec. III.B.2). 

Nonionic Surfactants Polyoxyalkylene Block Copolymers, edited by Vaughn M. Nace... 

The poloxamers manufactured by BASF (Cheadle, UK) are known as Pluronic PE block copolymers those manufactured by ICl (Cleveland, UK) as Synperonic PE nonionic surfactants. 

Nonionic surfactants, including EO-PO block copolymers, may be readily separated from anionic surfactants by a simple batch ion exchange method [21] analytical separation of EO-PO copolymers from other nonionic surfactants is possible by thin-layer chromatography (TLC) [22,23] and paper chromatography [24], and EO-PO copolymers may themselves be separated into narrow molecular weight fractions on a preparative scale by gel permeation chromatography (GPC) [25]. 

Ethylene oxide is an important intermediate chemical not only for the production of nonionic surfactants like fatty alcohol ethoxylates, alkylphenol ethoxy lates, or propylene oxide/ethylene oxide block copolymers, but also for manufacturing of anionic surfactants like alcohol ether sulfates. 

Surfactants used as lubricants are added to polymer resins to improve the flow characteristics of the plastic during processing they also stabilise the cells of polyurethane foams during the foaming process. Surfactants are either nonionic (e.g. fatty amides and alcohols), cationic, anionic (dominating class e.g. alkylbenzene sulfonates), zwitterionic, hetero-element or polymeric (e.g. EO-PO block copolymers). Fluorinated anionic surfactants or super surfactants enable a variety of surfaces normally regarded as difficult to wet. These include PE and PP any product required to wet the surface of these polymers will benefit from inclusion of fluorosurfactants. Surfactants are frequently multicomponent formulations, based on petro- or oleochemicals. 

V.M. Nace, Nonionic Surfactants Polyoxyalkylene Block Copolymers, Surfactant Science Series, Vol. 63, Marcel Dekker, New York, USA, 1996. 

Since this initial work there has been a plethora of literature on mesoporous molecular sieves. In addition to the silica and aluminosilicate frameworks similar mesoporous structures of metal oxides now include the oxides of Fe, Ti, V, Sb, Zr, Mn, W and others. Templates have been expanded to include nonionic, neutral surfactants and block copolymers. Pore sizes have broadened to the macroscopic size, in excess of 40 nm in diameter. A recent detailed review of the mesoporous molecular sieves is given in ref [73]. Vartuli and Degnan have reported a Mobil M41S mesoporous-based catalyst in commercial use, but to date the application has not been publicly identified.[74]. 

Chu, B. and Zhou, Z. (1996). Physical chemistry of polyoxyalkylene block copolymer surfactants. In Nonionic surfactants. Polyoxyalkylene block copolymers, Vol. 60, (ed. 

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