The addition of citric acid to A-PentOx-A resulted in an increase in viscosity compared to the neat polymer. This could be explained by the formation of H-bridges between the plasticizer's acid groups and the polymers amide groups. Through the presence of three acid groups per citric acid molecule, physical crosslinking between polymer and plasticizer could occur, leading to an increase in the viscosity values. While this suggested interaction between A-PentOx-A and citric acid was not further investigated, a decrease in viscosity was observed when triacetin, ethylene glycol or triethyl citrate were added. Due to the chemical structure of the polymers and the plasticizers, no stronger interactions between polymer and plasticizer, such as H-bonding, can be expected. A dependency of plasticizer on the polymer properties was also observed in the Tg of the polymer-plasticizer blends (Figure ). The addition of triethyl citrate, triacetin and ethylene glycol resulted in a decrease of the Tg from 52 °C to 47 -42 °C, respectively, whereas the addition of citric acid increased the Tg slightly to 53 °C.