Water-soluble oligomers

Oligomeric Vinylphosphonate. A water-soluble oligomer, Fyrol 76 [41222-33-7] is produced by reaction of bis(2-chloroethyl) vinylphosphonate and dimethyl methylphosphonate with elimination of all the chlorine as methyl chloride (127,128). This Hquid, containing 22.5% P, is curable by free-radical initiation, on cotton or other fabrics. Nitrogen components, such as A/-methylolacrylamide or methylolmelamines, are usually included in the finish, which can be durable to multiple launderings (129,130). 

TosoHaas Technical Report No. 10 Separation of Water-Soluble Oligomers by High Performance Gel Filtration Chromatogtaphy on TSKgel PWXL . 

Poly(HASCL) depolymerases are able to bind to poly(3HB)-granules. This ability is specific because poly(3HB) depolymerases do not bind to chitin or to (crystalline) cellulose [56,57]. The poly(3HB)-binding ability is lost in truncated proteins which lack the C-terminal domain of about 60 amino acids, and these modified enzymes do not hydrolyze poly(3HB). However, the catalytic domain is unaffected since the activity with water-soluble oligomers of 3-hy-droxybutyrate or with artificial water-soluble substrates such as p-nitrophenyl-esters is unaffected [55, 56, 58, 59]. Obviously, the C-terminal domain of poly(3HB) depolymerases is responsible and sufficient for poly(3HB)-binding [poly(3HB)-binding domain]. These results are in agreement ... 

The distillation residue (8-9 g) consists of water-soluble oligomers that can be saponified without loss of optical purity by heating at reflux with aqueous add for 15 hr. 

Podoll, R.T., K.C. Irvin, and S. Brendlinger. 1987. Sorption of water soluble oligomers on sediments. Environ. Sci. Technol. 21 562-568. 

Abiotic hydrolysis of linear, crosslinked and porous PCL resulted in formation of 6-hydroxyhexanoic acid (HHA) and water-soluble oligomers [73]. As seen in Fig. 4 the introduction of crosslinks considerably increased the hydrolysis rate and formation of monomeric 6-hydroxyhexanoic acid. This was mainly explained by the lower degree of crystallinity for the crosslinked PCL homopolymer. 

This short discussion of problems associated with stabilizing dispersions of PVAc and its copolymers leads to the conclusion that the hydrophilic nature of VAc make placement of stabilizing species (surfactant, charge, hydrated layer, etc.) difficult without incurring additional problems (decrease in rate of polymerization, increase in the concentration of water-soluble oligomers, increase in viscosity, etc.). As a result, a combination of approaches is often used in commercial latex production. The need for better surfactants, especially reactive surfactants, for the emulsion polymerization of vinyl monomers is still evident... 

Oligomers also may adversely affect product propoties. Tauer and Bdinisdi [173] reported that the degree of dehydrochlorination of PVC increased with increasing amount of water-soluble oligomers in the sample. NMR analysis showed that the oligomers, which are formed during the emulsion polym -ization of vinyl chloride, have a structure similar to PVC,... 

Charactaization of the water-soluble oligomers requires removal of the latex particles from the serum. This has been accomplished by ultrafiltration [163,164,166,174], serum replacement [167,168], or freeze-coagulation [173], followed by standard concentration techniques (e.g. evaporaton of water, or solvent extraction) or direct analysis of the aqueous solutions [163,164,166,174]. 

Thomson, B., Wang, Z., Paine, A., Lajoie, G., and Rudin, A., A Mass Spectrometry Investigation of the Water-Soluble Oligomers Remaining after the Emulsion Polymerization of Methyl Methacrylate, J. Polum. Set. Part A Polym. Chem., 33, 2297, 1995. 

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