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Relaxation time, activation energy, and reaction pathway determination of the poly(ethylene glycol dimethacrylate)–dopant (I2) interaction with the nuclear magnetic resonance technique

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Abstract

Conductive polymers were obtained with a new polymerization method in which UV light was used as a photochemical initiator. In a previous work, optimum irradiation times were determined to obtain high conversion percentages. The effect of dopants on the conductivity of the polymer poly(ethylene glycol dimethacrylate) (PEGDM) was studied with LiClO4 and I2 as a dopant. The most effective dopant concentration was determined by the measurement of conductivities. Through the tracing of the conductivity change at various temperatures during the reaction of PEGDM with the dopant, the activation energies of the interactions were calculated, and a method was developed to follow the kinetics of the polymerization reaction with a conductometric technique. This work presents a nuclear magnetic resonance (NMR) study of the same polymer prepared under the optimum conditions with the results obtained in a previous study. NMR spectroscopy was used to determine the relaxation time, rate constants, and activation energy of the polymer–dopant interactions. As a preliminary study, pyruvic acid was used, and for acid-catalyzed pyruvic acid/water reactions, the relaxation time, activation energy, and enthalpy change values (ΔH) were determined. With the same NMR technique, the reaction mechanisms of the polymerization, relaxation times, and rate constants of the polymer–dopant interactions were determined. The polymerization pathway was determined with NMR spectra; the results were confirmed by the calculation of the activation energies and bond-breaking energies. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100:5087–5101, 2006

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