Aqueous Free-Radical Polymerization of Non-Ionized and Fully Ionized Methacrylic Acid

被引:16
|
作者
Fischer, Eric Jean [1 ]
Storti, Giuseppe [1 ]
Cuccato, Danilo [1 ]
机构
[1] Swiss Fed Inst Technol, Inst Chem & Bioengn, Vladimir Prelog Weg 1, CH-8093 Zurich, Switzerland
来源
PROCESSES | 2017年 / 5卷 / 02期
基金
瑞士国家科学基金会;
关键词
methacrylic acid; free radical polymerization; modeling; propagation; termination; electrostatic interactions; electrostatic screening; kinetics; NMR; PROPAGATION RATE; KINETICS; TERMINATION; POLYELECTROLYTES; COPOLYMERIZATION; ACRYLAMIDE; MECHANISM; MONOMER;
D O I
10.3390/pr5020023
中图分类号
TQ [化学工业];
学科分类号
0817 ;
摘要
Water-soluble, carboxylic acid monomers are known to exhibit peculiar kinetics when polymerized in aqueous solution. Namely, their free-radical polymerization rate is affected by several parameters such as monomer concentration, ionic strength, and pH. Focusing on methacrylic acid (MAA), even though this monomer has been largely addressed, a systematic investigation of the effects of the above-mentioned parameters on its polymerization rate is missing, in particular in the fully ionized case. In this work, the kinetics of non-ionized and fully ionized MAA are characterized by in-situ nuclear magnetic resonance (NMR). Such accurate monitoring of the reaction rate enables the identification of relevant but substantially different effects of the monomer and electrolyte concentration on polymerization rate in the two ionization cases. For non-ionized MAA, the development of a kinetic model based on literature rate coefficients allows us to nicely simulate the experimental data of conversion versus time at a high monomer concentration. For fully ionized MAA, a novel propagation rate law accounting for the electrostatic interactions is proposed: the corresponding model is capable of predicting reasonably well the electrolyte concentration effect on polymerization rate. Nevertheless, further kinetic information in a wider range of monomer concentrations would be welcome to increase the reliability of the model predictions.
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页数:18
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