2.1. Materials
The polymer used was the biodegradable aliphatic polyester
poly(d,l lactic acid) (PDLLA) (12% content in d-lactide stereoisomer,
purchased from Galactic, Belgium) with Mw = 189,000 and
Mw/Mn = 2.8. The nanofiller used for the modifications was sodium
montmorillonite (NaMMT) (CEC = 92.6 mequiv/100 g clay) and was
purchased from Southern Clay Products (TX, USA). The commercially
organomodified montmorillonite (Cloisite 25A) was also
purchased from the same company. All amines, dichloromethane
(CH2Cl2), and triethylene glycol (used for the density measurements
of the porous materials) were obtained from Sigma–Aldrich