Res. Chem. Intermed.
, Vol. 34, No. 1, pp. 21–30 (2008)
Also available online - www.brill.nl/rci
Ionic and excited species in irradiated poly(vinyl chloride)
doped with aromatic admixtures: low temperature studies
J. MAYER and M. SZADKOWSKA-NICZE
Institute of Applied Radiation Chemistry, Technical University, Wróblewskiego 15, 93-590 Łód´z,
Received 9 May 2007; accepted 7 September 2007
Abstract—The inﬂuence of temperature (77–290 K) on the fate of dopant radical ions and respective
excited states in irradiated poly(vinyl chloride) (PVC) matrix doped with pyrene, (Py) and tris(2-
ethylhexyl) trimellitate (TOTM) is described. At 77 K dopant radical ions start to recombine via
tunneling charge transfer, leading to weak isothermal luminescence (ITL). The wavelength-selected
radiothermoluminescence (WS RTL) broad maxima observed for doped PVC in the temperature range
95–110 K have a similar origin, i.e., recombination of dopant radical ions via tunneling. Apart from
the peaks representing the absorption of dopant radical ions the absorption maximum at 411 nm
found for the PVC–Py system is attributed to Py–Cl adduct generated in Py
mechanisms involved in these processes are discussed.
Keywords: Poly(vinyl chloride); low-temperature radiolysis; pyrene; TOTM; radical ions; excited
Poly(vinyl chloride) (PVC), is the most widely used vinyl polymer in medical
products. In medical applications materials ‘free’ of microorganisms have to be
used and recently the technique of sterilization by ionizing radiation has been
applied as a common practice.
When exposed to ionizing radiation (e.g., gamma rays, beam of accelerated
electrons) PVC products undergo radiation-induced transformations inﬂuencing the
useful properties of the material. In order to decrease the negative effects of
irradiation, i.e., the hydrogen chloride (HCl) production, the mechanism of PVC
radiolysis has to be understood. Up to the present the radical mechanism of PVC
radiation-induced decomposition [1 –3] has been put into industrial practice.
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