This study investigated the characteristics of polyamines that have two or more amino groups in their structure. They are expected to show better performance than existing absorbents due to the increased number of amino groups that can react with CO2. A semi-batch type apparatus was used to measure the absorption capacity of CO2 at the temperature range of 313-353 K. The quantity of heat generated by the absorption of CO2 in the absorbents was measured with a differential reaction calorimeter (DRC) for comparison with those of aqueous solutions of MEA and DEA at 298 K. The absorbents were evaluated from the aspects of the absorption capacity of CO2 and heat of absorption, and the characteristics according to the increasing number of amino groups were considered. (C) 2014 Published by Elsevier B.V.