Caracterização de oxidos de manganes (IV) suportados em polietileno

AUTOR(ES)
DATA DE PUBLICAÇÃO

1987

RESUMO

The objective of this work was the characterization of manganese(IV) oxides supported on high and low-density polyethylene (HDPE and LDPE) and obtained by the immersion of the polymers in aqueous acidic solutions af potassium permanganate at 80°C. The oxides were characterizated rnorphologically; their zinc ion adsorption capacity was determinated and used to evaluate the surface area of the oxides. The following facts were verified: a) the amount of supported MnO2 increase with the irnrnersion time and are greater when the oxide is obtained in the presence of HNO3 and on HDPE (rather than when obtained in the presence of H2SO4 and on LDPE) ;b) the surface area of the oxides decreases with the immersion time and is greater for the oxides obtained in the presence of HNO3 and on HDPE than for the oxides obtained in the presence of H2S04 and on LDPE; c) both drying and aging the oxides lead to a decrease in surface area; d) scanning electron micrographies show that the dry oxide is a macroporous gel, with many cracks; e) the polymer surface is oxidized during the deposition processo The SO4 and NO3¨ ions influence was assigned to their adsorption on the Mno2 polymer chains. The greater masses obtained on LDPE were related to the greater mobility of the substrate chains. The decrease of the surface area and the opening of macropores and cracks was assigned to the gel contraction associated with polycondensation reactions. This fact was verified by the decrease of the micropores radius of gyration, measured by SAXS.

ASSUNTO(S)

polietileno oxido de manganes

ACESSO AO ARTIGO

Documentos Relacionados