接枝丙烯酰胺共聚物在水溶液中的缔合与黏弹行为

采用荧光探针研究了丙烯酰胺(AM)/4-乙烯苄基辛基酚聚氧乙烯(18)醚(VE)/2-丙烯酰胺基-2-甲基丙磺酸钠(NaAMPS)接枝共聚物(PAE)在水溶液中的疏水缔合作用,揭示了聚合物水溶液的超分子缔合结构与黏弹性能的相互关系。结果表明,在纯水和盐水溶液中,当聚合物浓度不高于0.1 g/L时,PAE主要以伸展的单分子链存在。随着PAE浓度的增加,分子间疏水缔合作用明显增强,疏水微区的非极性和尺寸均显著增加;当PAE浓度高于2 g/L时,缔合微结构的尺寸虽然增加,但其微区的非极性变化很小。当其浓度高于1.5 g/L时,由于缔合结构的形成,PAE在角频率0.05~50 rad/s范围内,PAE在纯水和盐水溶液中均主要表现为弹性行为。

Association and viscoelastic behaviors of the acrylamide-based graft polymer in aqueous solutions

Hydrophobic association of a graft terpolymer of acrylamide (AM), sodium 2-acrylamido-2-methylpropanesulphonate (NaAMPS) and p-vinylbenzyl-terminated octylphenoxy polyoxyethylene (18) ether (VE) in aqueous solutions was investigated with a fluorescent probe so as to discover the correlation of supramolecular microstructures of this terpolymer with viscoelastic properties in aqueous solutions. The results showed that the polymer remains mainly in the form of extended mono-molecule chains in pure-water or brine solutions as the polymer concentration is lower than 0.1 g/L, and the non-polarity and size of hydrophobic microdomains increase remarkably with increasing polymer concentration from 0.1 to 2.0 g/L because of evident strengthening of the intermolecular hydrophobic association. However, as the polymer concentration is higher than 2.0 g/L, the non-polarity of associating microstructures varies little though the size of associating microstructures increases substantially. The PAE polymer predominantly exhibits elastic behavior in unsalted water and brine solutions because of the formation of associating microstruetures within the range of 0.05~50 rad/s as the polymer concentration is higher than 1.5 g/L.