Time-resolved rheology as a tool to monitor the progress of polymer degradation in the melt state - Part II: Thermal and thermo-oxidative degradation of polyamide 11/organo-clay nanocomposites

TitleTime-resolved rheology as a tool to monitor the progress of polymer degradation in the melt state - Part II: Thermal and thermo-oxidative degradation of polyamide 11/organo-clay nanocomposites
Publication TypeJournal Article
Year of Publication2015
AuthorsFilippone, G, Carroccio, SC, Curcuruto, G, Passaglia, E, Gambarotti, C, Dintcheva, NT
JournalPolymer (United Kingdom)
Volume73
Pagination102 - 110
Date Published2015
ISBN Number00323861 (ISSN)
Keywordschemical analysis, Crosslinking, Crosslinking reaction, Degradation, Desorption, Elasticity, Filled polymers, MALDI-TOF, Mass Spectrometry, Matrix assisted laser desorption/ionization, Mechanical spectroscopy, Nanocomposite, Nanocomposites, Nanoparticles, Organic polymers, Organo-clay, Oxidative induction time, Polyamide 11, Polymer matrix composites, Pyrolysis, Rheology, Thermal and thermo-oxidative degradation, Thermal degradation, Thermo-oxidative degradation
Abstract

Abstract Thermal and thermo-oxidative degradation of nanocomposites based on polyamide 11 (PA11) and organo-modified clay (Cloisite® 30B) are studied in the melt state (T = 215 °C) via time-resolved mechanical spectroscopy (TRMS). The goal is assessing the potentiality of rheological analysis for studying polymer degradation in complex systems such as polymer nanocomposites, whose rheological response stems from the combination of the contributions of polymer and nanoparticles. We prove that a thorough analysis grounded on TRMS allows to isolate the effect of degradation of the polymer matrix, whose progress can be hence profitably monitored. Essentially the same degradation mechanisms as in neat PA11 are identified for the nanocomposite, but the kinetics of the thermo-oxidation processes are much faster in the presence of organo-clay. In particular, rheology promptly identifies cross-linking reactions since the early stage of the treatment in air. Matrix-assisted laser desorption/ionization and oxidative induction time measurements corroborate the conclusions drawn on the basis of rheological analyses, shedding light on the chemical aspects of PA11 degradation. Overall, rheological analysis confirms to be a valuable tool for monitoring polymer degradation even in case of inherently complex systems such as nanocomposites. In this case, however, the analysis can be difficult if the dynamics of the nanoparticles prevail over those of the polymer matrix, which is the case of nanocomposites at high filler contents. © 2015 Elsevier Ltd.

Short TitlePolymer