Polyoxyethylene sequence

Important parameters are the composition of the alcohol-water system [between 60-40 (vol/vol) and 30-70 (vol/vol)] and the length of the polyoxyethylene sequence. Most of the usual monomers can be used, with the exception of MM A if it is used alone (it can be used as a comonomer when the Tg of the resulting copolymer remains lower than 40°C). The latex displays good stability as well as good film properties. 

Another estimate of the incorporation yield of a styrenic surfmer of polyethylene oxide in batch copolymerization with styrene has been published recently. The polyethylene oxide absorbance can be estimated (using NMR) in the latex produced [72]. The incorporation yield was shown to be between 7-42%, most of the surfactant remaining in the serum. Latex stabillity involves a long enough polyoxyethylene sequence (around 50 units). At variance with saccharide surfactants [73], copolymerization of the styrene with a more hydrophilic monome such as methyl methacrylate tends to reduce the incorporation yield. 

Ethoxyl tion. Base-cataly2ed ethoxylation of aUphatic alcohols, alkylphenols, and fatty acids can be broken down into two stages formation of a monoethoxy adduct and addition of ethylene oxide to the monoadduct to form the polyoxyethylene chain. The sequence of reactions is shown in equations 20—22 ... 

Perret, R., and Skoulios, A., Synthese et caracterisation de copolymeres sequences polyoxyethylene/poly-e-caprolactone. 

Another important kind of addition polymerization is the formation of polyethers by the opening of epoxy ring compounds. Polyoxyethylene ( Carbowax ) is produced by a sequence of additions of ethylene oxide to an alcohol or amine, as initiator ... 

Some of the kinked units discussed in the previous section, such as —0— and — S—, are simple examples of flexible spacers that space the meso-genic units into separate structural sequences of smaller length-to-diameter ratios. Other segments often used as flexible spacers include oligomeric polymethylenes, polyoxyethylenes, polysiloxanes, and so forth. The following series of molecules, (3.5) with n = 1-8, make up one of the oldest examples of the flexible spacer concept in the molecular design of liquid crystals (Vorlander, 1927) ... 

Deleens G, Foy P and Marechal E (1977) Synth e et caracterisation de copolyconden-sats sequences (polyamide-set ether) III Etude de la reaction de polycondensation du polyamide-11 oj,ui -dicarboxylique et du polyoxyethylene u>,u> -dihydroxy. Determination des constantes de vitesse et de I nergie d activation, Eur Polym J 13 353-360. McGarthy S J, Meijs G F and Gunatillake P (1997) S5mthesis, characterization and stability of poly[(alkylene oxide) ester] thermoplastic elastomers, J Appl Polym Sci 65 1319-1332. 

Deleens C, Foy P and Marechal E (1977) Synthesis and characterization of copolycondensate sequences poly (amide-seg-ether) - III. Study of the polycondensation reaction of a ,a -dicarboxy polyamide-11 and a ,a -dihydroxy polyoxyethylene. Determination of the rate constants and the activation energy, Eur Polym J 13 353-360 (in French). 

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