Continuous hydrothermal synthesis of AlO(OH) nanorods as a clean flame retardant agent--颗粒学报PARTICUOLOGY

Elbasuney, S. (2015). Continuous hydrothermal synthesis of AlO(OH) nanorods as a clean flame retardant agent. Particuology, 22, 66-71. https://doi.org/10.1016/j.partic.2014.11.011

Continuous hydrothermal synthesis of AlO(OH) nanorods as a clean flame retardant agent

Sherif Elbasuney ^*

School of Chemical Engineering, Military Technical College, Kobry El-Koba, Cairo, Egypt

10.1016/j.partic.2014.11.011

Volume 22, October 2015, Pages 66-71

Received 26 July 2014, Revised 14 November 2014, Accepted 24 November 2014, Available online 23 March 2015, Version of Record 4 August 2015.

E-mail: sherif_basuney2000@yahoo.com

Highlights

• AlOOH with consistent quality was manufactured by controlled continuous hydrothermal synthesis.

• Post-mixing temperature control and surface modification play an essential role in the synthesis.

• Continuous flocculation of AlOOH from its mother liquor was adopted.

Abstract

Aluminum-oxide-hydroxide (AlOOH) is a clean and non-toxic flame retardant. There have been many trials for the fabrication of ultrafine AlOOH. Two main approaches exist for nano-AlOOH synthesis: reactive precipitation and batch hydrothermal synthesis. Both approaches are laborious and time consuming with poor control of particle morphology. We report on the novel continuous flow manufacture of AlOOH nanorods with controlled morphology (particle size and shape) by hydrothermal synthesis. AlOOH was harvested from its mother liquor (colloidal solution) using poly(acrylamide-co-acrylic acid) copolymer as a flocculating agent. The developed AlOOH shape and size, crystalline phase, thermal stability, and endothermic heat sink action were investigated by transmission electron microscopy, X-ray diffractometry, thermogravimetric analysis, and differential scanning calorimetry, respectively. The phase transition of AlOOH to Al₂O₃ was demonstrated by conducting different X-ray diffractometry scans from 400 to 700 °C. These results may provide an option for the continuous synthesis of nano-AlOOH as a clean and non-toxic flame retardant with excellent thermal stability. Consequently, enhanced flammability properties can be achieved at low solids loading.

Graphical abstract

Keywords

Flame retardants; Hydrated minerals; Hydrothermal synthesis

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