1. 西安交通大学能源与动力工程学院,西安,710049
2. 西安工程大学环境与化学工程学院,西安,710048
网络首发:2009-01-10,
纸质出版:2009
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杨靖 1, 2, 陈杰瑢 1. 甲基修饰二氧化硅气凝胶的红外光谱和热分析研究[J]. 西安交通大学学报, 2009,43(1):114-118.
Fourier Transform Infrared Spectroscopy and Thermal Analysis of Silica Aerogel Modified by Methyl Groups[J]. 2009, 43(1): 114-118.
采用红外光谱(FTIR)和热重-微分热重(TG-DTG)法研究了甲基修饰二氧化硅气凝胶样品在空气环境中的热分解
利用Coast-Redfern积分法和Achar微分法相结合的方法
求出了甲基修饰二氧化硅气凝胶在热分解过程中的活化能和指前因子.结果表明:Si—CH
3
的热稳定温度在450 ℃左右
至600 ℃时样品中的—CH
3
已完全分解; 在空气气氛下
—CH
3
的热分解过程经历了4个阶段
各阶段具有不同的热动力学机理函数
其活化能分别为60.36、191.25、77.34和203.53 kJ/mol
指前因子分别为7.71×10
7
、6.02×10
18
、2.49×10
3
和2.04×10
11
s
-1
.
The thermal decomposition of silica aerogel modified by methyl groups in air is investigated by Fourier transform infrared spectroscopy(FTIR)and thermogravimetry(TG)-differential thermogravimetry(DTG). The activation energy and frequency factor are obtained with Coast-Redfern integral method and Achar differential method. The results show that the thermal stable temperature of Si—CH
3
is about 450 ℃ and the —CH
3
groups are decomposed entirely as heated to 600 ℃. There are four steps in the —CH
3
group thermal decomposition
with different mechanism functions. The activation energy is 60.36
191.25
77.34 and 203.53 kJ·mol
-1
and the frequency factor is 7.71×10
7
6.02×10
18
2.49×10
3
and 2.04×1
0
11
s
-1
for the four steps
respectively.
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