Thermal properties of electrospun Poly(lactic acid) membranes

Abstract

In the present work, PLA electrospun membranes were processed by electrospinning and characterized by electron scanning microscopy and thermal analysis. The polymer membrane showed a random fiber distribution with a mean diameter of 1 μm (± 300 nm). Differential scanning calorimetry experiments showed that the membrane has a glass transition, cold crystallization and melting temperatures of 54, 90 and 151 ºC, 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 can 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 models are in good agreement with the value of the activation energy calculated by 2 the Kissinger method. The activation energies of PLA calculated by the three methods were 176, 148 and 157 kJ.mol-1, respectively, similar to the values observed in PLA films.