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Špírková M, Pavličević J, Aguilar Costumbre Y, Hodan J, Urbanová M, Krejčíková S. Mechanically strong waterborne poly(urethane‐urea) films and nanocomposite films. J Appl Polym Sci 2021. [DOI: 10.1002/app.50011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Milena Špírková
- Institute of Macromolecular Chemistry CAS Prague Czech Republic
| | - Jelena Pavličević
- University of Novi Sad, Faculty of Technology Novi Sad Novi Sad Serbia
| | - Yareni Aguilar Costumbre
- Institute of Macromolecular Chemistry CAS Prague Czech Republic
- Institute of Scientific and Technological Research of San Luis Potosi (IPICYT) San Luis Potosí Mexico
| | - Jiří Hodan
- Institute of Macromolecular Chemistry CAS Prague Czech Republic
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Thermal-Resistant Polyurethane/Nanoclay Powder Coatings: Degradation Kinetics Study. COATINGS 2020. [DOI: 10.3390/coatings10090871] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In the present study, thermal degradation kinetics of polyurethane (PU) powder coatings reinforced with organo-modified montmorillonite (OMMT) was investigated. PU nanocomposites were prepared in different concentrations of 1, 3, and 5 wt.% of OMMT via the extrusion method. The microstructure of the nanocomposites was observed by scanning electron microscope (SEM) illustrating uniform dispersion of OMMT nano-clay platelets in the PU matrix except for the sample containing 5 wt.% nano-palates. Thermal degradation kinetics of the PU nanocomposite was investigated using thermogravimetric analysis (TGA) at different heating rates of 5, 10, and 20 °C/min. The results showed that the initial decomposition temperatures were shifted toward higher values (more than 40 °C for T5% and up to 20 °C for T10%) by introducing the nano-clay to the PU matrix. Friedman, Kissinger–Akahira–Sunose (KAS), Flynn–Wall–Ozawa (FWO), and modified Coats-Redfern iso-conversional methods were applied to model the decomposition reaction and the activation energy of the nanocomposite powder coatings. Overall, the presence of nano-clay increased the activation energy of the PU degradation up to 45 kJ/mol, when compared to the blank PU, which suggests very high thermal stability of nanocomposites. The Sestak-Berggren approach proposed a good approximation for the reaction model, especially at low temperatures. Thus, PU decomposition was detected as an autocatalytic reaction, which was suppressed by the barrier effect of OMMT nano-palates intercalated with polymer chains.
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