Interaction between iodine and ethyl cellulose

Abstract

ABSTRACT:Interaction between iodine and ethyl cellulose was investigated by immersing ethyl cellulose membranes in aqueous iodine-iodide solution (iodine doping) and incorporating iodine in the solution from which the membrane was cast. Oxygen and nitrogen permeabilities in iodine-doped ethyl cellulose decrease with an increase in the concentration of iodine in the dopant solution up to 0.003 mol L Ϫ1 and increase sharply at higher iodine concentrations, and ultraviolet-visible and far-infrared spectra indicate formation of a charge transfer complex. Differential scanning calorimetry of both types of membrane shows changes in the characteristic phase transitions of ethyl cellulose after iodine treatment, including the crystal-liquid crystal transition that has been reported to occur in ethyl cellulose. Further evidence for liquid crystal phases has been found from circular dichroism. X-ray photoelectron spectroscopy of iodine-doped ethyl cellulose films indicates that the iodine is present in two different chemical states, probably l 3 Ϫ and l 2 .

Molecular iodine/polymer complexes

“…Also, the release capacity of iodine from the tablets when immersed into phosphate buffer (pH = 6.5) at 37°C was nearly 0.55 and 0.3 mg for I 2 HPC and I 2 EC, respectively, after about 7 h of immersion. Wang and Easteal [88] studied the inter action of EC with iodine by immersing EC membranes in aqueous iodineiodide solution at room temperature for 24 h. The iodinedoped EC membrane was colored from orange to brown, depending on the iodine concentration. Iodine absorption increased rapidly with iodine concen tration, at concentrations lower than about 0.01 mol·l 1 .…”

Antimicrobial Polyurethane Thermosets Based on Undecylenic Acid: Synthesis and Evaluation

“…The presence of the I 3d peak (I 3d5/2 at 618.5 eV and I 3d3/2 at 631.1 eV proved the formation of iodine complexes in the surface layer of modified PU. Moreover, the splitting of the peaks in the I 3d region confirmed the formation of species …”

Mucoadhesive tablet releasing iodine for treating oral infections

“…After iodine complexation, it was found that the endotherm at 228°C became harder to detect, while a sharp endotherm appears at 188°C. This was explained16 as the result of EC becoming more crystalline due to complex formation, chain ordering, and to iodine sublimation, because its sublimation temperature is 180°C. This explanation fits the correlation demonstrated in this study, between the areas under the melting endotherm and the amounts of iodine, with straight line and with r 2 = 0.97.…”

“…The mechanism of interaction between cellulose and iodine has been studied, nevertheless without reaching an unequivocal conclusion. Wang et al16 suggested that the interaction between iodine and EC proceeds as follows:…”