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

POLYMER

卷:73

Article

Filippone, G.¹  Carroccio, S. C.²  Curcuruto, G.²  Passaglia, E.³  Gambarotti, C.⁴  Dintcheva, N. Tz.⁵ 

[1] Univ Naples Federico II, Dipartimento Ingn Chim Mat & Prod Ind INSTM Conso, I-80125 Naples, Italy

[2] CNR IPCB UOS Catania, CNR, I-95126 Catania, Italy

[3] UOS Pisa, Ist Chim Composti Organometall ICCOM CNR, Pisa, Italy

[4] Politecn Milan, Dipartimento Chim Mat & Ingn Chim Giulio Natta, I-20133 Milan, Italy

[5] Univ Palermo, Dipartimento Ingn Civile Ambientale Aerosp Mat, I-90128 Palermo, Italy

关键词: Rheology;    Thermal degradation;    Thermo-oxidative degradation;    Polyamide 11;    Nanocomposite;    Organo-clay;    MALDI-TOF;   

DOI  :  10.1016/j.polymer.2015.07.042

来源: Elsevier

【 摘 要 】

Thermal and thermo-oxidative degradation of nanocomposites based on polyamide 11 (PA11) and organo-modified clay (Cloisite (R) 30B) are studied in the melt state (T = 215 degrees 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. (C) 2015 Elsevier Ltd. All rights reserved.

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