Rheology and conductivity techniques were used to systematically investigate the aggregation behaviors of sodium lignosulfonates (SL) in the concentrated solutions
and the influences of inorganic salts (NaCl
Na2SO4)
ureas and straight-chain alcohols (methanol
ethanol
n-propanol) on the aggregation behaviors of the concentrated SL solutions were also explored. The experimental results indicated that the addition of inorganic salts was in favor of the electrostatic repulsion shielding effect and the solvent polarity enhancement
which promoted the formation of larger SL aggregates
however
the result was just opposite after the addition of ureas due to the destruction of hydrogen bondings and the weakening of aggregation interactions. In the meantime
when a small amount of straight-chain alcohols were added in the SL solutions
their non-polar carbon chains could insert into the hydrophobic cores of SL aggregates
which resulted in the decrease of the aggregation degree. However
the excessive addition of straight-chain alcohols was favorable to the formation of aggregates. This may be attributable to the increase of the hydrophobic interaction and the aggregation degree
which was caused by the raised pH. Based on electrostatic repulsions
hydrogen bondings and hydrophobic interactions
the aggregation behaviors of SL in the concentrated solutions were explained reasonably.