| Popis: |
Volatile radiolysis products of six medical polymers were identified by TDS–GC–MS after sterilizing doses of ca 25 kGy. All the polymers—PS, MABS, PA-6, PVC, PE, and PP—produce detectable amounts of volatiles which remain trapped in the polymer matrix for considerable times; the products and their concentrations are characteristic for each plastic. The main products of PS are acetophenone, benzaldehyde, phenol, 1-phenylethanol, and phenylacetaldehyde; their concentrations are ca one order of magnitude below the residual styrene/styrene dimer levels. Some trace products are formed with still lower yields—with the exception of benzene these are also oxidized aromatic compounds. The same volatiles are observed in MABS, which additionally gives some aliphatic compounds. PA-6 yields pentanamide as the main product, plus traces of some homologous amides. The main products of PVC and PP are fragments of additives, i.e., of stabilizers and phenol-type antioxidants, respectively. The PE produces only traces of hydrocarbons, aldehydes, ketones, and carboxylic acids, which largely disappear within weeks. The effects of irradiation on polymer pellets and injection-molded parts are comparable. The implications of our results for radiation detection and for the safety of irradiated devices and packaging materials are briefly discussed. |
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