Hyperbranched polyesters as biodegradable and antibacterial additives.

Herein, we present novel hyperbranched poly(amino-ester)s functionalized with quaternary ammonium salts (QAS-HPAEs). These materials can be used as antibacterial and biodegradable additives for mixing with non-active polymers. The chemical structure and thermal properties of the HPAEs were studied. All QAS-HPAEs were stable until 192 °C, which makes their thermal blending with other polymers possible. Blending polycaprolactone (PCL) as a biodegradable polymer with QAS-HPAEs improved its surface and bulk hydrophilicity, while partially decreasing its elastic modulus and tensile strength. Mixing 10 wt% of QAS-HPAEs in PCL resulted in a film with high contact-killing activity against E. coli and B. subtilis and faster degradability in the presence and absence of esterase. The activity of esterase was inhibited in the presence of a higher content of QAS-HPAEs (20 wt%).