Spectroscopic study of chemical modifications induced by swift heavy ions on polymers: the contribution of the CIRIL Platform and the CIMAP Laboratory

CIRIL, 30 years of interdisciplinary research at GANIL

Ngono-Ravache, Yvette^1

Centre de Recherche sur les Ions, les Matériaux et la Photonique, UMR6252 CEA/CNRS /ENSICAEN/Université de Caen-Basse Normandie, CIMAP-CIRIL-Ganil, BP 5133, Caen Cedex 05

14070, France^1

关键词: Electronic process;    Electronic stopping power;    Excitation density;    Linear energy transfer;    Radiation-induced oxidation;    Residual gas analysis;    Spectroscopic method;    Spectroscopic studies;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/629/1/012006/pdf
DOI  :  10.1088/1742-6596/629/1/012006

来源: IOP

【 摘 要 】

This paper gathers results obtained on the chemical ageing of polymers, at the CIRIL platform, using Swift heavy ions (SHI) from the GANIL accelerator. Swift heavy ions induce high values of electronic stopping power or LET (Linear Energy Transfer) and deposit their energy in the polymer through electronic processes, in a few nanometer size cylinder centered on the ion path. This results in huge local doses and dose rates. Both defects created in the polymer chain and gas release were quantified using spectroscopic methods (FTIR and Residual gas analysis (RGA)). Defects created in polymers submitted to SHI can be separated in two main series: defects common to all ionizing radiations and defects specific to SHI. A common trend of the evolution of these defects, under inert environment, is the following: 1) for the first group of defects, in most of the polyolefins, there is a limited (if inexistent) effect of LET on the radiation chemical yield of creation at low doses. Among defects of this first series, the behavior of vinyl groups is particular, 2) LET effect on SHI specific defects (triple bonds and cumulenes) is tremendous. Triple bonds (alkynes, alkyl or aryl cyanates) are created after a LET threshold value, depending on the polymer chemical structure. The dose effect on macromolecular defects, under inert environment, is also presented. The study of the LET effect on gas release, in various polyolefines, gives an insight on the mechanism of bond cleavage in presence of high ionization and excitation densities. Finally, few results on radiation-induced oxidation are presented. Compared to low-ionizing radiations, oxidation is reduced and unsaturated bonds are created under SHI.