Structural Modificationand Variation in the Kinetics of Isoconversional Phenomena: A Study on the Effect of Gamma Irradiation on Poly (Ethylene Oxide)

TL;DR

This study investigates how gamma irradiation affects the thermal, crystalline, and structural properties of Poly (Ethylene Oxide) in powder and solution forms, revealing dose-dependent modifications useful for tailoring material properties.

Contribution

It provides new insights into the dose-dependent structural and kinetic modifications of PEO under gamma irradiation, correlating DSC and FTIR results with microstructural changes.

Findings

Crystallinity increases up to 20 kGy in powder form, then decreases.

Solution form shows initial crystallinity enhancement followed by decline.

Gamma irradiation induces new functional groups and cross-linking in PEO.

Abstract

Interactions of Poly (Ethylene Oxide) [PEO] and gamma irradiation of variable doses (1-30 kGy) on the thermal, crystalline and structural properties are investigated using DSC and FTIR technique. Two states of PEO, viz. powder (P-S-series) and solution (P-L-series) are subjected to irradiationand are castinto uniform film.DSC results revealed steady increment of crystallinity upto 20 kGy for P-S-series after which amorphous region increases till 30 kGy. Conversely, P-L-series shows much enhanced crystallinity retained within low regime of 7 kGy, followed by sharp declining trend till 30 kGy. DSC is also used to determine the multiple kinetic processes in an isoconversional PEO melting using Friedman differential analysis. Gamma irradiation is found to generate newer functional groups established from FTIR study. FTIR spectra of generated peaks viz. -C=O, -C=C- exhibit scission dominated irradiation induced in presence of air. Contribution of cross-linkage which is higher in liquid irradiation is also proved from FTIR. The studied observations of DSC and FTIR are correlated with polymer microstructures. Hence, selective irradiation dose could be determined with respect to the exposed state (solid or solution) of polymer and utilized to tailor the properties of PEO.