Viscosity Studies on Polypropylene Glycol and Its Blend

Viscosity studies have been made on polypropylene glycol (PPG) of different molar masses [500, 1000, 2000] in both low and medium concentration ranges [lower concentration range 0 to 1% (w/v) and medium concentration range 1 to 10% (w/v)] in toluene, in the temperature range of 303 to 333 K. The effect of concentration on the activation energy of flow was calculated. It was observed that the activation energy of flow is greater for molar masses of 1000 and 2000 than that of the solvent. The effect of molar mass was also analyzed, and it was indicated that in PPG, a molar mass of 1000 might represent a transition state for the molecule from one shape to another shape. An attempt has also been made to blend PPG 2000 with PPG 500 (concentration 1% (w/v)), for various compositions of the blend. The miscibility nature of the blend was analyzed through viscosity studies and other techniques. The blend showed immiscibility. In this study the activation energy of flow for PPG in toluene was calculated and also the miscibility of two molar masses of PPG was investigated through viscosity studies. This work clearly shows that a viscosity study can be used for analyzing the miscibility of two polymers.