Hyperbranched azo-polymers derived from a pyrazolone-based AB2 type monomer: aggregation behavior in aqueous and non-aqueous media

A hyperbranched polyamide was synthesized from an AB2 type azo monomer in a self-polycondensation process. The hydrophilic core containg hetarylazo chromophore and carboxilic acid terminals was treated with monomethyl ethyleneglycol to modify the periphery and prepare a non-associative derivative. The two hyperbranched azo-polymers showed different solubility and aggregation behavior in aquous and non-aquous media. The polyacid form (PA) dispersed in neutral and acidic aqueous solution using ultrasonic waves showed stable colloid at pH=7, while precipitated gradually during overnight in acidic solution. Viscometry investigation of dilute solutions of the PA in DMF showed indications of aggregation state of the polymer. The morphology of the PA in solid state was considered by SEM on powder and dried dispersed form which represented aggregated morphology. Further investigations are continuing on the thermal analysis and dyeing properties of the synthesized polymers.