EstabilizaÃÃo radiolÃtica do poli(metacrilato de metila) industrial

AUTOR(ES)

Katia Aparecida da Silva Aquino

DATA DE PUBLICAÇÃO

2005

RESUMO

Poly(methyl methacrylate), PMMA, Acrigel, a Brazilian polymer, is used in the manufacture of medical supplies sterilizable by ionizing radiation. However, when PMMA is gammairradiated it undergoes main chain scissions, which promote molecular degradation causing reduction in its physical properties. Therefore, radiolytic stabilization of PMMA is important for to become it commercially radiosterizable. In this work we investigated the radiolytic stabilization of PMMA by using HALS (Hindered Amine Light Stabilizer) additive, commercialy used for photo and thermo oxidative stabilization of polymers. The investigation of the radiation-induced main chain scissions was carried out by viscometric method. The additive added to the polymer system at 0.3 % w/w promotes a molecular radioprotection of 61%. That means a reduction of G value (scissions/100 eV) from 2.6 to 1.0. In addition, the glassy transition temperature (Tg) of PMMA (no additive), significantly changed by radiation, does not change when PMMA (with additive) is irradiated. TGA analysis showed that the additive promotes thermal stability to the system, increasing decomposition temperature of PMMA. Spectroscopy analysis, FT-IR and RMN (1H), showed that the radioprotector additive added to the system does not change the PMMA structure. Analysis on mechanical (tensile strengh and elongation at break) and optical (yellowness index and refractive index)properties showed a good influence of the additive on polymer system.

ASSUNTO(S)

radiaÃÃo engenharia nuclear industrial estabilizaÃÃo radiolitica metacrilato de metila

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