Thermal Decomposition Kinetics and Mechanisms of PE100 Compound for Gas Pipes

doi:10.19491/j.issn.1001-9278.2020.10.009

Abstract

Abstract:

Thermogravimetric analysis was used to determine the thermal decomposition process of PE100 compound for gas pipes at 2， 5， 10， 20 °C/min under four different heating rates in nitrogen. The thermal decomposition kinetics and mechanisms of PE100 compound were investigated by the Kissinger， Flynn-Wall-Ozawa and Coats-Redfern methods. The Toop method was used to evaluate the lifetime of PE100 compound at different temperatures. The results indicated that the thermal decomposition of PE100 compound presented a typical one-step reaction， and its average activation energy was 327.8 and 304.6 kJ/mol obtained from the Kissinger and Flynn-Wall-Ozawa methods， respectively. Moreover， the lnA value of apparent prefactor for PE100 compound was 53.9 min^-1. Among the 12 common thermal decomposition models， the cylindrical symmetric contraction （R2） was considered as the most suitable mechanism to describe the thermal decomposition process of PE100 compound. The lifetime of PE100 compound obtained by Kissinger and Flynn-Wall-Ozawa method at 50 °C was 7.4×10⁸ and 7.9×10⁷years， respectively. However， the lifetime decreased rapidly with a rise of temperature.

Key words: PE100 compound, thermal decomposition kinetics, activation energy, apparent prefactor

CLC Number:

TQ 325.1⁺2

HUANG Guojia, LI Lushui, XU Qingyong, XIN Mingliang. Thermal Decomposition Kinetics and Mechanisms of PE100 Compound for Gas Pipes[J]. China Plastics, 2020, 34(10): 51-55.

Figures/Tables 7

References 19

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β/℃·min^-1	T_{-5 %}/℃	T_p/℃
2	430.2	460.0
5	446.4	475.9
10	454.1	484.0
20	457.0	490.9

β/℃·min^-1	T_{-5 %}/℃	T_p/℃
2	430.2	460.0
5	446.4	475.9
10	454.1	484.0
20	457.0	490.9

α	E/kJ?mol^-1	lnA/min^-1
均值	304.6	53.9
0.2	319.6	56.2
0.4	310.6	54.9
0.6	302.5	53.6
0.8	286.4	50.9

α	E/kJ?mol^-1	lnA/min^-1
均值	304.6	53.9
0.2	319.6	56.2
0.4	310.6	54.9
0.6	302.5	53.6
0.8	286.4	50.9

序号	符号	反应模型	g(α)	模型机理	E_/kJ·mol^-1	lnA/min^-1	R²
1	A1、F1	Avrami?Erofeev	?ln(1?α)	随机成核和生长（n = 1）	399.2	63.1	0.997 4
2	A2	Avrami?Erofeev	[?ln(1?α)]^1/2	随机成核和生长（n = 1/2, m = 2）	193.3	29.7	0.997 2
3	A3	Avrami–Erofeev	[?ln(1?α)]^1/3	随机成核和生长（n = 1/3, m = 3）	124.7	18.4	0.997 0
4	D1	1D diffusion	α²	一维扩散	585.8	91.9	0.973 1
5	D2	2D diffusion	(1?α)ln(1?α) +α	二维扩散(Valensi方程)	648.2	101.5	0.983 4
6	D3	3D diffusion	[1?(1?α)^1/3]²	三维扩散(Jander方程)	726.6	112.9	0.992 7
7	D4	4D diffusion	(1?2α/3)? (1?α)^2/3	三维扩散(Ginstling?Brounshtein 方程)	674.0	104.3	0.987 1
8	R1	Plane symmetry	α	相界面控制(一维移动)	286.7	44.37	0.971 9
9	R2	Cylinder symmetry	1?(1?α)^1/2	相界面控制(圆盘状)	337.8	52.2	0.988 5
10	R3	Spherical symmetry	1?(1?α)^1/3	相界面控制(球状)	357.1	55.0	0.992 4
11	F2	Second order	?1+(1?α)^?1	单个粒子上的随机双核成核（n = 2）	553.9	88.6	0.992 0
12	F3	Third order	[?1+(1?α)^?2]/2	单个粒子上的随机三核成核（n = 3）	744.7	119.9	0.970 4