Blendas de poli(epicloridrina) e poli(estireno-co-metacrilato de metila)

AUTOR(ES)
DATA DE PUBLICAÇÃO

1997

RESUMO

The miscibility of blends can not be explained by favorable interactions between the different components when at least one component is a copolymer. Repulsive interactions between monomeric units have been indicated as one of the reasons for the phenomenon of a miscibility window. The purpose of this work was the determination of the miscibility window in blends of poly(epichlorohydrin) (PEPI) with copolymers of styrene and methyl methacrylate P(S-co-MMA). Thus, copolymers with concentrations of 10, 25, 50, 75 and 90 mole % of styrene were synthesized by radical polymerization in solution, as well as the homopolymers polystyrene and poly(methyl methacrylate). After that, blends of these polymers and PEPI with concentrations of 20, 40, 50, 60 and 80 wt % were prepared. The characterization of the blends by Differential Scanning Calorimetry has shown the existence of partial miscibility in the system PEPI/PMMA and imiscibility in the system PEPI/PS. Blends of PEPI anel copolymers exhibited miscibility until 25 mole % of styrene, but the presence of this monomer caused the broadening of the glass transition, which characterizes the microheterogeneity of these mixtures. When the concentration of styrene was increased up to 75 mole %, phase separation was observed in the blends; however, mixtures of PEPI and copolymers containing and higher content of styrene (90 mole%) showed miscibility in some compositions. The effects observed were explained by the partial miscibility of the blends PEPI/PMMA, the monomer distribution in he copolymer chains, as well as the repulsive and attractive interactions between the monomers in the P(S-co-MMA) copolymer and PEPI homopolymer.

ASSUNTO(S)

copolimerização polimeros mistura (quimica)

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