Role of organo-modifier and metal impurities of commercial nanoclays in the photo-and thermo-oxidation of polyamide 11 nanocomposites

Nadka Tzankova Dintcheva, Giovanni Filippone, Giusy Curcuruto, Martina Ussia, Sabrina Carola Carroccio, Raniero Mendichi, Daniela Zampino

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Abstract

The photo-oxidative degradation processes of bio-based PA11 nanocomposites containing montmorillonite (MMT) and the organo-modified Cloisite®30B were investigated to discriminate the influence of organo-modified components on the polymer durability. Indeed, despite the extensive studies reported, there are still ambiguous points to be clarified from the chemical point of view. To this aim, UV-aged materials were analyzed by Size Exclusion Chromatography (SEC), Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) and Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS). This enabled determining changes in both chemical structure and Molar Masses (MMs) induced by light, heat and oxygen exposure. The addition of organo-modified nanoclays strongly affected the PA11 light durability, triggering the macromolecular chains scission due to the typical αH, Norrish I and II mechanisms. However, the main contribution in boosting the photo-oxidative degradation is induced by iron impurities contained into the clays. Conversely, thermo-oxidation process performed at 215 °C was unambiguously affected by the presence of the organo-modifiers, whose presence determined an enhancement of crosslinking reactions.
Original languageEnglish
Number of pages12
JournalPolymers
Volume12
Publication statusPublished - 2020

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • Polymers and Plastics

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