Thermal properties of electrospun poly(lactic acid) membranes
Poly(lactic acid) (PLA) electrospun membranes were obtained by electrospinning and characterized by scanning electron microscopy (SEM) and thermal analysis. The polymer membranes showed a random fiber distribution with a mean diameter of 1 m (±300 nm). Differential scanning calorimetry (DSC) experiments showed that the membranes had a glass transition, cold crystallization, and melting temperatures of 54, 90, and 151°C, respectively. The kinetic study of thermal degradation of PLA under a nitrogen atmosphere was performed by means of thermogravimetry (TGA). It was found that the thermal decomposition kinetics of PLA could be interpreted in terms of a multi-step degradation mechanism. Several theoretical models were applied to the TGA data. The activation energies obtained by the Broido and Ozawa-Flynn-Wall (OFW) models were in good agreement with the value of the activation energy calculated by the Kissinger method.