Enhanced Thermal Properties of Zirconia Nanoparticles and Chitosan-Based Intumescent Flame Retardant Coatings

• Published in: Applied sciences Vol. 9; no. 17; p. 3464
• Main Authors: Rao, Tentu Nageswara, Hussain, Imad, Lee, Ji Eun, Kumar, Akshay, Koo, Bon Heun
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.09.2019
• Subjects: Acids; Ammonium; Boric acid; Chitosan; Coatings; Epoxy resins; Flame retardants; Flammability; Gravimetric analysis; Heat; Heat release rate; Heat transfer; intumescent flame retardant coatings; Melamine; Morphology; Nanoparticles; Scanning electron microscopy; SEM; Steel alloys; TGA; Thermal analysis; Thermal properties; Thermal stability; Thermogravimetric analysis; X-ray spectroscopy; XRD; Zirconia; Zirconium alloys; Zirconium dioxide; ZrO2 NPs
• ISSN: 2076-3417; 2076-3417
• DOI: 10.3390/app9173464

Zirconia (ZrO2)-based flame retardant coatings were synthesized through the process of grinding, mixing, and curing. The flame retardant coatings reinforced with zirconia nanoparticles (ZrO2 NPs) were prepared at four different formulation levels marked by F0 (without adding ZrO2 NPs), F1 (1% w/w ZrO2 NPs), F2 (2% w/w ZrO2 NPs), and F3 (3% w/w ZrO2 NPs) in combination with epoxy resin, ammonium polyphosphate, boric acid, chitosan, and melamine. The prepared formulated coatings were characterized by flammability tests, combustion tests, and thermogravimetric analysis. Finally, char residues were examined with scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The peak heat release rate (PHRR) of the controlled sample filled with functionalized ZrO2 NPs was observed to decrease dramatically with increasing functionalized ZrO2 NPs loadings. There was an increase in the limit of oxygen index (LOI) value with the increase in the weight percentage of ZrO2 NPs. The UL-94V data clearly revealed a V-1 rating for the F0 sample; however, with the addition of ZrO2 NPs, the samples showed enhanced properties with a V-0 rating. Thermal gravimetric analysis (TGA) results revealed that addition of ZrO2 NPs Improved composite coating thermal stability at 800 °C by forming high residual char. The results obtained here reveal that the addition of ZrO2 NPs in the formulated coatings has shown the excellent impact as flame retardant coatings.