Molecular structure characterization of hyperbranched polyesteramides

The molecular structure of a series of hyperbranched polyesteramides was studied using size exclusion chromatography (SEC), mass spectrometry (MS) and small-angle neutron scattering (SANS). Products with increasing molecular mass were obtained through the polycondensation of in situ produced AB(2)-like monomeric units. Electrospray ionization MS indicates that narrow SEC fractions consist of different isomers, the number of which increases with molecular mass. Molecular mass moments and polydispersity numbers increase with polycondensation degree. The SANS measurements and SEC-DV data yield values for the polymers fractal dimension, which can be rationalized in the framework of percolation theory that originally was designed for randomly branched polymers. Randomly branched polymer behavior in this particular case possibly results from a side reaction involving reactivity among B-end groups.