Temperature and Concentration Dependence of Viscosity of Binary Mixtures of PEG-1000+water

Viscosities of binary mixtures of polyethylene glycol-1000 (PEG-1000) and water were measured precisely in the temperature range 293.15-343.15 K at atmospheric pressure using a high precision viscometer. Viscosity data were used to calculate the activation energy of viscous flow. The activation energy was observed to increase with increase in the concentration of aqueous solutions of PEG which indicated that more energy is required to move the molecule inside the structure with increase in concentration. The measured data provided better understanding to explain the behaviour of macromolecules with respect to change in concentration and temperature. The results were discussed in the light of polymer-solvent interactions. At lower concentration range, the molecules exhibit weak interaction due to dominant repulsive force and at higher concentration the entanglement of polymer chain increases. In view of greater force of interaction between solute and solvent molecules forming hydrogen bonding, there will be an increase in interaction with temperature and concentration.