We report on the inverse thermogelation of aqueous solutions of high molecular weight Hydroxy-PropylCellulose (HPC). The gelation process is investigated at different polymer concentrations, in the range 4 divided by 16% (w/w). For each concentration, different heating rates are considered, in order to explore the effects on the sol-gel transition. Our findings corroborate the scenario proposed in literature for the thermoreversible gelation of cellulose derivatives, according to which the sol-gel transition is governed by an interplay of liquid-liquid phase separation and gelation. Gelation occurs in the polymer-rich phase via enhanced hydrophobic interactions between polymer chains at high temperature. At low heating rates, the phase separation proceeds significantly before the gelation occurs, creating more coarsened phases. As a consequence, the polymer network is less percolated and results in a weaker gel. Such an effect is more evident in less concentrated solutions characterized by a shorter terminal relaxation time, that is, faster polymer diffusion. As HPC concentration and heating rates are increased, the dissipative capacity of the final gel, expressed by the value of the phase angle at high temperatures, becomes nearly independent on polymer concentration and heating rate. However, the absolute values of the viscoelastic moduli of the formed gel increase with both HPC concentration and heating rate. The temperature window where transition occurs slightly narrows down with increasing concentration. (C) 2017 Elsevier Ltd. All rights reserved.