Structure, Solution Aggregation and UV Curing of Hyperbranched Poly(ester-amine)s with Terminal Acrylate Groups

Abstract

A series of hyperbranched poly(ester-amine)s (defined as HPEA-1–HPEA-5) with terminal acrylate groups were synthesized through Michael addition between piperazine (A2) and trimethylolpropanetriacrylate (TMPTA) (B3) under molar ratios ranged from 1/2 to 1/1.08. As increasing the molar ratio between piperazine and TMPTA, the degree of branching (DB), number average molecular weight (Mn), polydispersity index (Mw/Mn) and glass transition temperature (Tg) of the polymers increased accordingly. Due to their amphiphilic flexible structures, the polymers could form stable aggregates in acetone–acidic water selective solution at volume ratio of 1/25. The influences of polymer structures and the solution pH on the size and size distribution of the aggregates were measured by dynamic light scattering (DLS). The results indicated that smaller size was obtained for the polymer with higher Mn, while the size distribution changed in accordance with Mw/Mn. At lower solution pH, both smaller size and narrower size distribution were obtained. Furthermore, the polymer dispersions were irradiated by UV light to initiate polymerization of acrylate groups within the aggregates. The resulting cured particles possessed decreased size compared with the size of the corresponding aggregates as determined by DLS and transmission electron microscopy (TEM).