Telechelic Associative 聚合物参考资料.pdf

Light Scattering for the Masses™ Telechelic Associative Polymers any applications of polymer characterization don’t require HPLC; in fact, many samples Mcan´t be separated due to limitations of the separation technology or of the sample itself. This is exactly the case with telechelic associative polymers. These polymers are hydrosoluble, hydrophobically- modifi ed with hydrophobic groups in the extremities of the hydrophilic chain. Simply put, they cannot be characterized by HPLC in any solvent, due to prob- lems of aggregation and absorption. Accordingly, the weight-average molar mass of these polymers must be determined by using the “micro batch” mode of opera- tion for the DAWN. In this application note, we report the character- ization of a telechelic polymer that consists of a poly- acrylamide and a hydrophobic initiator “azo” derived of the 4,4’-Azobis(4-cyanopentanoic acid) modifi ed with 12 or 16 carbons. The reported samples were dis- Figure 1 shows the absolute weight-average molar mass solved in formamide to specifi c concentrations. The 6 computed to be [2.128 ±0.031] x 10 daltons. DAWN EOS detector was employed, and the samples were injected directly to the cell of fl ow of the instru- ment. The data were collecting and analyzed using the ASTRA software’s Zimm plot module. The angular dependence—extrapolated to zero angle—yields the root mean square radius; the concen- tration dependence—extrapolated to zero concentra- tion—gives the second virial coeffi cient (A ), and the 2 intercepts of b