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Thermal decomposition of cellulose ethers
Author(s) -
Li XinGui,
Huang MeiRong,
Bai He
Publication year - 1999
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/(sici)1097-4628(19990929)73:14<2927::aid-app17>3.0.co;2-k
Subject(s) - cellulose , thermal decomposition , decomposition , thermogravimetry , thermostability , activation energy , nitrogen , chemistry , methyl cellulose , kinetics , reaction rate constant , polymer chemistry , chemical decomposition , materials science , organic chemistry , inorganic chemistry , physics , quantum mechanics , enzyme
The thermostability and thermal decomposition kinetics of methyl cellulose (MC), ethyl cellulose (EC), carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), and hydroxypropyl–methyl cellulose (HPMC) were characterized in nitrogen and air by thermogravimetry (TG). Various methods of kinetic analysis were compared in case of thermal degradation of the five cellulose ethers. The initial decomposition temperature ( T d ) , temperature at the maximum decomposition rate ( T dm ), activation energy ( E ), decomposition reaction order ( n ), and pre‐exponential factor ( Z ) of the five cellulose ethers were evaluated from common TG curves and high‐resolution TG curves obtained experimentally. The decomposition reactions in nitrogen were found to be of first order for MC, EC, and HPMC with the average E and ln Z values of 135 kJ/mol and 25 min −1 , although there were slight differences depending on the analytical methods used. The thermostability of cellulose ethers in air is substantially lower than in nitrogen, and the decomposition mechanism is more complex. The respective average E , n , ln Z values for HEC in nitrogen/air were found to be 105/50 kJ/mol, 2.7/0.5, and 22/8.3 min −1 , from constant heating rate TG method. The respective average E , n , and ln Z values for three cellulose ethers (EC/MC/HPMC) in air are 123/144/147 kJ/mol, 2.0/1.8/2.2, 24/28/28 min −1 by using high‐resolution TG technique. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2927–2936, 1999