2A2+ BB‘B‘ ‘ Approach to Hyperbranched Poly(amino ester)s

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.