Mecanismos de aumento da solubilidade aquosa de copolimeros-bloco por efeito de hidrotropos

AUTOR(ES)
DATA DE PUBLICAÇÃO

1998

RESUMO

A better understanding ofthe mechanism leading to increase in aqueous solubility of block copolymers promoted by hydrotropes (additives), is very important in terms of the applicability of these polymers. This project was divided in three parts: Study on the aqueous solubility of the copolymers as function of temperature, in pure solutions and in the presence of hydrotropes. Solubility changes were followed by determining the solution cloud points, allowing the proposition of a sequence of efficacy for the additives studied. Calorimetric measurements allowed the determination of enthalpies of transfer (DtH) for copolymers from water to additive solutions. These additives solutions ere investigated by using a series of techniques: determination of cloud points, surface tension measurements, following their effect on the solubility of methyl yellow and their enthalpies of dilution (DdilH). The obtained results suggest htat hydrophobic self-association is an important step in their mechanism of action causing copolymer solubility increase.

ASSUNTO(S)

calorimetria polimeros agentes ativos de superficies

ACESSO AO ARTIGO

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