2A 2 + BB′B″ approach to hyperbranched poly(amino ester)s

Abstract

Hyperbranched poly(amino ester)s were synthesized via a novel 2A 2 + BB′B″ approach, represented by the Michael addition polymerization of a trifunctional amine, 1-(2-aminoethyl)piperazine (AEPZ) (BB′B″-type monomer), with a double molar diacrylate, 1,4-butanediol diacrylate (BDA) (A 2-type monomer). The formation of B″A 2-type intermediate via its precursor, B′B″A-type intermediate, was verified by in situ monitoring the polymerizations using NMR and MS (ESI). High molecular weight hyperbranched poly(BDA2-AEPZ1) with vinyl terminal group was obtained from the B″A 2-type intermediate when the polymerization was performed in DMSO at 70°C for ca. 101.0 h. Then the terminal vinyl group was tuned to primary, secondary, and tertiary amine, as verified by NMR. The radius of gyration (R g) and hydrodynamic radius (R h) of hyperbranched poly(BDA2-AEPZ1)-MPZ were measured using small-angle X-ray scattering (SAXS) and laser dynamic light scattering (LDLS), respectively, and the ratio of R g/R h of ca. 1.0 confirmed the hyperbranched structure. Molecular weights, glass transition temperatures (T g), and thermal stability (T d) of hyperbranched poly(amino ester)s were characterized using GPC, DSC, and TGA, respectively. © 2005 American Chemical Society.