Abstract In this study, we compared the effect of n-pentane and ice-water bath on removing the thermal effect in the poly ( p-phenylene terephthalamide) (PPTA) polymerization process. The results indicate that the n-pentane can help to transfer the reaction heat faster and better. Adding suitable amount of n-pentanes into the PPTA preparation process not only improve the heat transfer, but also reduce the motor power in the polymerization process. Moreover, the introduction of n-pentane properly does not result in decrease of the inherent viscosity ( η inh) of polymer. Instead, it leads to increased viscosity of polymer during the PPTA preparation process. The results indicate that n-pentane can effectively transfer the reaction heat and avoid overheating during the polymerization of PPTA.