Structural and chemical changes of cellulose fibres under low energy ion implantations

The structural and chemical changes occurring during low energy ion implantation of Argon Nitrogen and Oxygen in cellulose materials are reported. The samples were treated to three different ions at various fluences and energies. The ion beam modification of the samples showed significant structural and chemical changes at the surface as investigated with scanning electron microscopy and Raman spectroscopy. Results found a threshold and beyond this threshold various microscopic changes were seen at surface including discoloration, pitting and fusing of fibres. These changes were consistent with ion beam damage of the polymer chain and later show molecular changes consistent with mild pyrolysis of the fibres. However, the calculated temperature rise from the implantation process is insufficient to explain such pyrolysis to occur. A mechanism is proposed for the observed structural and chemical changes.