Thermooxidative degradation of injection-moulded sepiolite/polyamide 66 nanocomposites

A. Yebra-Rodríguez, C. Fernández-Barranco, M. D. La Rubia, A. Yebra, A. B. Rodríguez-Navarro, J. Jiménez-Millán
2014 Mineralogical magazine  
Clay/polymer nanocomposites (CPN) exhibit improved technical properties compared to their microand macro-counterparts. Nevertheless, thermal degradation of CPN may limit the applicability of these hybrid materials. In this paper accelerated ageing (110°C and 150°C) was performed in injection moulded pure polyamide 66 (PA66-S-0 samples) and polyamide 66 reinforced with 5 wt.% sepiolite (PA66-S-5 samples) CPN. Polymer degradation was monitored by the amount of newly formed carbonyl bonds. The
more » ... onyl bonds. The carbonyl indices obtained indicate that degradation occurs to a greater extent as the temperature of the ageing process increases. Moreover, the degradation increases with time at the highest treatment temperature (150°C). On the other hand, the occurrence of carbonaceous silicates in the nanocomposite samples at high temperatures yields greater thermal stability of sepiolite/PA66 nanocomposites compared to pure PA66. Furthermore, the sepiolite nanofibres maintain their position in the reticulated semicrystalline structure. In agreement with those results, differential scanning calorimetry and X-ray diffraction analyses show that the motion of the amide groups in the polymer chains are constrained by the well dispersed sepiolite.
doi:10.1180/minmag.2014.078.5.09 fatcat:kkwnj2qvbzcstkqvut2rg5byti