Syneresis measurement of the HPAM-Cr (III) gel polymer at different conditions: An experimental investigation

In this paper, the syneresis percentage of the HPAM (15% hydrolysis) - Cr (III) gel polymer system is obtained by using the bottle testing. The effects of different parameters including temperature, polymer concentration, cross-linker concentration, pH and different additives on the syneresis variation, as well as on the syneresis initiating time are studied. The Results show that, by increasing the polymer concentration and temperature, the percentage of syneresis decreases and increases, respectively. To achieve the maximum stability time, the weight ratio of polymer to cross-linker is obtained 40 to 1 (p/c = 40). It is observed that by adding some additives such as NaCl, MgCl2 and NaHCO3 to gel polymer solution, the percentage of syneresis of the gel polymer changed. Furthermore, then results of the pH tests assert that the best range of the pH to achieve the most stable polymeric gel is between 5.5 and 7.5.