Kinetic study of radical polymerization. VII. Investigation into the solution copolymerization of acrylonitrile and itaconic acid by real‐time ¹H NMR spectroscopy

Abstract

Free radical solution copolymerization of acrylonitrile (AN) and itaconic acid (IA) was performed with DMSO-d 6 as the solvent and 2,2 0 -azobisisobutyronitrile (AIBN) as the initiator. Weight ratio of the monomers to solvent and molar ratio of initiator to monomers were constant in all experiments. The initial comonomer composition was the only variable in this study. On-line 1 H NMR spectroscopy was applied to follow individual monomer conversion. Mole fraction of AN and IA in the reaction mixture (f) and in the copolymer chain (F) were measured with progress of the copolymerization reaction. Overall monomer conversion versus time and also compositions of monomer mixture and copolymer as a function of overall monomer conversion were calculated from the data of individual monomer conversion versus time. Total rate constant for the copolymerization reaction was calculated by using the overall monomer conversion versus time data and then k p /k t 0.5 was estimated. The dependency of k p /k t 0.5 on IA concentration was studied and it was found that this ratio decreases by increasing the mole fraction of IA in the initial feed. The variation of comonomer and copolymer compositions as a function of overall monomer conversion was calculated theoretically by the terminal model equations and compared with the experimental data. Instantaneous copolymer composition curve showed the formation of alternating copolymer chain during copolymerization reaction.

An In‐Situ NMR Study of Radical Copolymerization Kinetics of Acrylamide and Non‐Ionized Acrylic Acid in Aqueous Solution

“…The group of Mahdavian has studied AM homopolymerization in aqueous solution [28] as well as various copolymerization in organic solution. [37][38][39][40] Three criteria for running in-situ NMR experiments were reported: [28] 1) a reaction rate that is less than the scanning rate, 2) solubility of the polymer in the solvent, and 3) distinguishable monomer/ polymer peaks so that monomer composition and conversion can be determined. A fourth criterion, namely that isothermal conditions are maintained, should be added.…”

A Critical Overview of Sensors for Monitoring Polymerizations

“…On‐line 1 H NMR has also been used in different kinetic studies by several authors 451–454. A series of studies of the radical polymerization of STY/itaconic acid and acrylonitrile/itaconic acid using this technique were also carried out 455–459. Landfester et al456 demonstrated that it is feasible to use on‐line solid‐state 1 H‐ and 13 C NMR spectroscopy in the study of emulsion polymerization of BA.…”

Studies on the Amidoximation of Polyacrylonitrile Films: Influence of Synthesis Conditions

“…Several methods have been followed to improve their hydrophilic properties, such as coating, adsorption, surface plasma treatment, surface hydrolysis, surface graft polymerization and chemical modification 1–4. Various vinyl and acrylic monomers, have been reported as a comonomer to modify PAN properties 5–7. Ulbricht et al4 introduced carboxylic groups by grafting acrylic acid under pure helium plasma, whereas Zhao et al8 used argon plasma for the grafting in PAN.…”