Heavy ion radiolysis of organic materials

Radiation-induced decomposition of anion exchange resins

“…(Radiation-chemical yields are given here in the traditional unit of molecules of product/100 eV of energy absorbed, 1 molecule/100 eV = 0.1 lmol/J.) These yields are relatively low and comparable with H 2 yields typically found with aromatic compounds [22]. The NO À 3 form of the resin shows the greatest radiation stability, probably because of the anion's ability to scavenge precursors to the formation of H 2 .…”

The radiolysis of poly(4-vinylpyridine) quaternary salt ion exchange resins

“…The yields of H 2 with c-rays and with 5 MeV 4 He ions in liquid pyridine radiolysis are 0.027 and 0.12 molecule/100 eV, respectively [18]. H 2 yields are found to be similar for liquid benzene and solid polystyrene and a similar relationship is expected for pyridine and P4VP [13]. The precursor of H 2 in liquid pyridine radiolysis is thought to be a highenergy singlet excited state above the S1 state [18,41].…”

“…The radiolysis of organic polymer materials leads to the production of gases, especially H 2 , depending on the nature of polymers or the type of ionizing radiation [11][12][13][14][15][16][17]. The production of H 2 can be explained from simple radical chemistry (e.g., H atom-H atom combination, H atom abstraction, and disproportionation) following C-H bond breakage due to the energy deposited by the passage of ionizing radiation or from the unimolecular decomposition of excited singlet states [13,16].…”

“…The production of H 2 can be explained from simple radical chemistry (e.g., H atom-H atom combination, H atom abstraction, and disproportionation) following C-H bond breakage due to the energy deposited by the passage of ionizing radiation or from the unimolecular decomposition of excited singlet states [13,16]. In general, H 2 yields are found to increase with increasing LET (linear energy transfer = ÀdE/dx) of the incident radiation because of changes in the track geometry as defined by the local region where the energy is deposited.…”

“…In general, H 2 yields are found to increase with increasing LET (linear energy transfer = ÀdE/dx) of the incident radiation because of changes in the track geometry as defined by the local region where the energy is deposited. For instance, the yield of H 2 is fourfold greater with 5 MeV 4 He ions than with c-rays for both liquid benzene and polystyrene [13]. Reillex TM resins carry a repeated unit of a pyridine analogue and the radiation chemistry is expected to correlate closely with the radiolysis of liquid pyridine, which also exhibits an increase in the yield of H 2 with increasing LET [13,[18][19][20].…”