General nonlinear rheological behavior of associative polymers

摘要: Shear thickening is very common in telechelic associative polymers. Yet, it not a universal characteristic of the whole class Here, more general features behavior are investigated. In particular, nonlinear rheological properties have been studied for both hydrophobically modified ethoxylated urethanes and alkali-soluble emulsions (HASE) A known failure Cox-Merz rule viscosities. The equivalent relation first normal stress examined here, parallelism with results viscosities has observed. More pronounced similarities between telechelics complex HASE systems can be seen some other properties. dynamic moduli display strain hardening at intermediate strains all but lowest frequencies, even when no shear detected steady state flow. linear relaxation functions differ quite strongly among However, they specific non-linear relaxation. It includes short time followed by softening starting long times. indicate that same microstructural mechanisms responsible classes polymer.