Thermal stability of the structure of fullerene-containing composites based on epoxy resin

The study investigated the influence of fullerenes on the thermal decomposition of epoxy resin using thermoprogrammed desorption mass spectrometry (TPD-MS) and Raman spectroscopy. Special attention was paid to changes in the polymer matrix degradation mechanism upon addition of fullerenes at low concentrations (0.01–0.1 wt. %). It has been found that a fullerene content of 0.05 wt. % ensures the greatest thermal stability of the composite, with a pronounced suppression of heavy decomposition fragments and a predominance of light volatile products. This indicates an alteration of the kinetics and pathways of thermodegradative processes in the presence of the nanofiller. The effect of fullerene content on the activation energy of thermal decomposition was analyzed, revealing that under certain conditions fullerenes can both retard and accelerate polymer degradation. This dual behavior is likely related to the introduction of structural defects in the polymer matrix, which affect the stability of chemical bonds. The physical mechanisms of fullerene action are discussed in terms of phonon relaxation, changes in electronic transport, and molecular mobility within the polymer/nanofiller interphase. Raman spectra of the epoxy-fullerene composites show significant differences compared to those of the neat resin, confirming the impact of fullerenes on its structural properties. The low intensity of the characteristic fullerene bands in the composite spectra is attributed to the filler’s low concentration, while observed band shifts point to local stresses in the polymer matrix arising during curing. These results provide deeper insight into the stabilization mechanisms of epoxy-based polymer composites by fullerenes and help to define the optimal conditions for their use as functional nanoadditives. The observed enhancement of thermal resistance underscores the effectiveness of fullerenes in suppressing thermodegradative processes and highlights their promise for high-temperature polymer applications.