Weight oxide chain length

Since there are many different types of nonionic detergents and the individual types may also have different ethylene oxide chain lengths, reference must be established to a standard substance with a known molecular weight this is, of course, not necessary if it is known which nonionic surfactant is present in the water sample. 

The fatty alcohol is converted to the acetate and both ethylene and propylene oxides are converted to their diacetates, apparently quantitatively. The mixture is analysed by gas chromatography, which separates the glycol diacetates sufficiently for quantitative determination. If the method were scaled up by a factor of 10 or 20, it would be easy to separate the reaction products and analyse them by alkaline hydrolysis to determine, for example, the molecular weight of the alcohol and the alkylene oxide chain length. 

Nuclear magnetic resonance monitoring of the synthesis of amphiphilic copolymers has also been reported by Larazz et al. [174] for the copolymerization of a methacrylic macromonomer with amphiphilic character derived from Triton X-100 (MT) with acrylic acid (AA). In situ H NMR analysis was used to monitor comonomer consumption throughout the copolymerization reactions, initiated by AIBN in deuterated dioxane, at 60 °C. The results from two different approaches used by the authors to estimate the reactivity ratio of the macromonomer indicate that AA is less reactive than the macromonomer MT and a model monomer with lower molecular weight but same structure, suggesting that methacrylic double bond reactivity was not affected by poly(oxyethylene oxide) chain length. 

Table 6.27 lists approximate values of molecular weight and ethylene oxide and propylene oxide chain lengths for the poloxamers, and the designation of poloxamers and the commercial Pluronic surfactants. 

The relationship between water solubility and the degree of ethoxylation (polyethylene oxide chain length) is well understood for alcohol ethoxylates. When the degree of ethoxylation is expressed as average weight-percent, an alcohol... 

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