In work highly crystalline beta sheets of silk nanocrystals (SNCs) have been studied for their effect on the thermal stability of poly (lactic acid) (PLA) during multiple reprocessing. Stable onset degradation temperature was obtained for PLA-SNC nanocomposite (T-5% similar to 334 degrees C), and compared to neat poly (lactic acid) (NPLA), which drastically reduces from 336 degrees C (first cycle) to 322 degrees C (fifth cycle). The activation energies were estimated using isoconversional Kissinger-Akahira-Sunose and Flynn-Wall-Ozawa methods. Stable activation energy values (similar to 130 kJ/mol) were obtained for SNC-PLA at three consecutive extrusion cycle. Whereas in the case of NPLA, it significantly reduces from similar to 150 kJ/mol (first cycle) to similar to 110 kJ/mol (second cycle). Nelder-Mead simplex method was used to optimize the kinetic parameters of nucleation and growth model (A2); which was observed to be the best fit of the experimental thermogravimetric analysis (TGA) data. Decomposition products were analyzed by Thermogravimetry coupled Fourier transform infrared spectroscopy. (C) 2016 Elsevier B.V. All rights reserved.