Characterization of tea polyphenols as potential environment-friendly fire retardants

International Conference on Energy Engineering and Environmental Protection 2017

能源学;生态环境科学

Yao, Fengqi^1 ; Zhai, Chunjie^1,2 ; Wang, Haihui^1 ; Tao, Junjun^1

State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, ANHUI

230026, China^1

Department of Forest Fire Protection, Nanjing Forest Police College, Nanjing, JIANGSU

210023, China^2

关键词: Aerial oxidation;    Differential scanning calorimeters;    Elevated temperature;    Environment friendly;    Heat insulation property;    Mass spectroscopy;    Oxidation properties;    Thermogravimetric analyzers;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/121/2/022016/pdf
DOI  :  10.1088/1755-1315/121/2/022016

学科分类：环境科学（综合）

来源: IOP

【 摘 要 】

In this work we investigated the oxidation properties of tea polyphenols and their potential as the fire retardants. Two types of tea polyphenols were adopted, which were extracted from red tea and green tea leaves, respectively. Their macroscopic performance during pyrolysis and oxidation at elevated temperatures were examined by using a heating furnace. Mass change, heat evolution and gas products of tea polyphenols during heating in air were also monitored by using a thermo-gravimetric analyzer (TGA) integrated with a differential scanning calorimeter (DSC) in conjunction with online Fourier Transform Infrared Spectroscopy (FTIR) and mass spectroscopy (MS). A tea polyphenol sample first becomes a brown semi-fluid after heating, and gradually turns into highly-porous black chars with significantly expanded volume. By raising the temperature to ∼550 °C at a rate of 10 °C/min, the mass of a sample reduces by nearly 70% to form a large quantity of inert gases that are mainly composed of H2O and CO2. It was found that the aerial oxidation products of tea polyphenols in the solid phase possess good heat insulation property; meanwhile, the substantial release of a lot of water and its evaporation during oxidation of tea polyphenols removes a large amount of heat from a sample located in a heating environment. The heat insulation of tea polyphenols may withstand up to 550 °C. The present work confirms tea polyphenols as potential superior and environment-friendly fire retardants.