Oxyethylene content

Oxyethylene Content (apparent) Not less than 60.5% and not more than 65.0%, calculated as ethylene oxide (C2H4O), on the anhydrous basis. 

Oxyethylene Content (apparent) Determine as directed under Oxyethylene Determination, Appendix VII, using 70 mg of sample, accurately weighed. 

Assay for Oxyethylene Content Not less than 70.0% and not more than 74.0% of oxyethylene groups (—C2H40—), equivalent to between 97.3% and 103.0% of Polysorbate 20, calculated on the anhydrous basis. 

Tetronic [BASF]. TM for a nonionic tetra-functional series of polyether block polymers ranging in physical form from liquids through pastes to finable solids. They are polyoxyalkylene derivatives of ethylenediamine. Physical state varies with molecular weight and oxyethylene content, 100% active. 

Consequently, from the data in this section and in Section IIA above, it appears that some chemical structures in the surfactant molecule that promote biodegradability (such as increased length and linearity of the hydrophobic group or decreased oxyethylene content) increase its toxicity to or bioconcentration in marine organisms. 

Aqueous solutions of POE nonionics, if the oxyethylene content is below about 80%, become turbid on being heated to a temperature known as the cloud point, following which there is separation of the solution into two phases. This phase separation occurs within a narrow temperature range that is fairly constant for... 

In POE polyoxypropylene block copolymers, wetting power appears to improve as the molecular weight of the polyoxypropylene portion of the molecule is increased and to be at a maximum when the molecule contains the minimum oxyethylene content consistent with solubility in the aqueous phase at the use temperature. 

In a study of POE straight-chain amines (Ikeda, 1984), the best wetting among isomeric materials was shown by compounds with two oxyethylene groups of approximately equal oxyethylene content attached to the nitrogen. Here, again, a more compact branched, structure produced bettter wetting. 

A similar detergency maximum at almost the same oxyethylene content has been observed in the removal of oily soil from metal surfaces using similar surfactants in an alkaline, built formulation (Komor, 1969). The maximum here is at 68% oxyethylene (about 11 oxyethylene units per nonylphenol) at bath temperatures from 40 to 80°C. For a series of polyoxyethylenated nonrandom linear alkylphenols with Cg-Cig alkyl chains, optimum removal of sebum soil from cotton at 49°C and 50 and 300 ppm water hardness was obtained at 63-68% oxyethylene content (Smithson, 1966). A study of the removal of oily soil from cotton and permanent press cloths, and of clay from permanent press cloths by commercial POE alcohols, showed that POE Ci2-Ci4 alcohols with 60% or greater ethylene oxide content achieved the best soil removal (Cox, 1989). 

Effect of Oxyethylene Content on Stability. The processing instability of TPU elastomers based on PPG 2000 can be overcome by the use of ethylene oxide "tipped" PPG polyols, especially those containing high levels of oxyethylene groups, e.g., 30% to 45% by weight. The improved stability of the polymers based on such polyols is demonstrated in Table 2. 

TABLE 15.5. Empirical Constants Relating CMC and Oxyethylene Content for Various Hydrophobic Groups in Nonionic Surfoctants [Eq. (15.21)]... 

This series of moderate-foaming ethoxylated nonylphenols is available in a range of oxyethylene content. This is one of the more widely used and best known classes of surfactants. Using members of the series, either singly or in combination, the forraulator can develop a variety of products. 

The diacetate content, proportional to the oxyethylene content of the original polymer is determined by gas chromatography. The procedure is calibrated against polyols of known molecular weight and oxyalkylene content. 

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