Association behavior of singly chain-end hydrophobically-modified poly(vinyl alcohol) in aqueous solution

The association behavior of hydrophobically-modified poly(vinyl alcohols), HMPVAs, bearing a single hydrophobic modifier (dodecyl group) located at on e end of the polymer chain, was investigated in aqueous solution using the techniques of pulsed gradient spin echo nuclear magnetic resonance (PGSE NM R) spectroscopy and viscometry. In comparison to control polymers lacking h ydrophobic modification, at concentrations above 2.5 wt% HMPVAs exhibited s lower diffusion, as measured using PGSE NMR, and higher viscosity, as measu red using viscometry. The results are consistent with the formation of inte rmolecular association structures consisting of approximately 9 polymer cha ins. The finding that singly chain-end HMPVAs form intermolecular hydrophob ic associations suggests that such polymers may prove useful as latex rheol ogy modifiers.