Hydrophobically end-capped polyethylene-oxide urethanes: 2. Modelling their association in water

Associative thickeners of the end-capped polyethyleneoxide urethane type are well known to form aggregates in aqueous solutions but there is a lack of studies dealing with the determination of the association mechanisms and with the size and form of these aggregates. We show for a given example that a combination of light scattering and viscosity experiments may produce a rather good description of these phenomena by interpreting them through theories of association and models of branched polymers. It is concluded that the aggregates look like statistically branched polymers, the junction points being formed by the association of approximately four hydrophobic chain ends.