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Silva, Williams B. da; Vasconcelos, Henrique M. de; Aquino, Katia Aparecida da S.; Araujo, Elmo S.
Associacao Brazileira de Energia Nuclear, Rio de Janeiro, RJ (Brazil)2009
Associacao Brazileira de Energia Nuclear, Rio de Janeiro, RJ (Brazil)2009
AbstractAbstract
[en] Commercial poly(methyl methacrylate) (PMMA) is used as medical supplies, which is sterilized by gamma irradiation at 25 kGy dose. However, when the PMMA is exposed to gamma rays it undergoes main chain scissions with changes in its properties. Samples of commercial PMMA containing a Hindered Amine Stabilizer (PMMA-HAS) and samples containing a salt mixture of CuCl2/KI (PMMA-salt) both at 0.3wt% concentration were investigated. The PMMA samples were purified by re-precipitation in methanol. The samples were irradiated with gamma radiation (60Co) at room temperature in air at dose range of 15-100 kGy. The viscosity- average molecular weight (Mv) was analyzed by viscosity technique. Comparison of viscosity results obtained before and after irradiation of PMMA showed a decrease in Mv values on irradiated samples with the increase in dose, reflecting the random scissions that occurred in the main chain. However the decrease on Mv is less in PMMA-HAS samples than control PMMA. The G value (scissions/100 eV of energy transferred to the system) obtained by viscosity analysis were used to calculated the protection value of HAS on PMMA matrix. The HAS showed a protection of 61% on PMMA molecules exposed to gamma irradiation. No efficiency action of salt mixture was observed on radiolytic degradation of PMMA. On the other hand the CuCl2/KI mixture influenced the mechanical behavior of PMMA and the HAS additive increased the maximum thermal degradation temperature of PMMA matrix. (author)
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Source
2009; [9 p.]; INAC 2009: International nuclear atlantic conference. Innovations in nuclear technology for a sustainable future; Rio de Janeiro, RJ (Brazil); 27 Sep - 2 Oct 2009; 16. Brazilian national meeting on reactor physics and thermal hydraulics; Rio de Janeiro, RJ (Brazil); 27 Sep - 2 Oct 2009; 9. Brazilian national meeting on nuclear applications; Rio de Janeiro, RJ (Brazil); 27 Sep - 2 Oct 2009; 1. Meeting on nuclear industry; Rio de Janeiro, RJ (Brazil); 27 Sep - 2 Oct 2009; Published only in CD-Rom. Code: e13715fullpaper.pdf
Record Type
Miscellaneous
Literature Type
Conference; Numerical Data
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ALCOHOLS, ALKALI METAL COMPOUNDS, BETA DECAY RADIOISOTOPES, BETA-MINUS DECAY RADIOISOTOPES, CHEMICAL ANALYSIS, CHEMICAL RADIATION EFFECTS, CHEMICAL REACTIONS, CHLORIDES, CHLORINE COMPOUNDS, COBALT ISOTOPES, COPPER COMPOUNDS, COPPER HALIDES, DATA, DECOMPOSITION, DEFORMATION, DOSES, ELECTROMAGNETIC RADIATION, ESTERS, GRAVIMETRIC ANALYSIS, HALIDES, HALOGEN COMPOUNDS, HYDROXY COMPOUNDS, INFORMATION, INORGANIC PHOSPHORS, INTERMEDIATE MASS NUCLEI, INTERNAL CONVERSION RADIOISOTOPES, IODIDES, IODINE COMPOUNDS, IONIZING RADIATIONS, ISOMERIC TRANSITION ISOTOPES, ISOTOPES, MECHANICAL PROPERTIES, MINUTES LIVING RADIOISOTOPES, NUCLEI, NUMERICAL DATA, ODD-ODD NUCLEI, ORGANIC COMPOUNDS, ORGANIC POLYMERS, PHOSPHORS, POLYACRYLATES, POLYMERS, POLYVINYLS, POTASSIUM COMPOUNDS, QUANTITATIVE CHEMICAL ANALYSIS, RADIATION EFFECTS, RADIATIONS, RADIOISOTOPES, THERMAL ANALYSIS, TRANSITION ELEMENT COMPOUNDS, YEARS LIVING RADIOISOTOPES
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