Facile Synthesis and Characterization of Hyperbranched Poly(ether amide)s Generated from Michael Addition Polymerization of In Situ Created AB 2 Monomers YING LIN, 1,2 ZHONG-MING DONG, 1,2 XIAO-HUI LIU, 1 YUE-SHENG LI 1 1 State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China 2 Graduate School of the Chinese Academy of Sciences, Changchun 130022, China Received 23 March 2007; accepted 18 April 2007 DOI: 10.1002/pola.22175 Published online in Wiley InterScience (www.interscience.wiley.com). ABSTRACT: A new straightforward strategy for synthesis of novel hyperbranched poly (ether amide)s from readily available monomers has been developed. By optimizing the reaction conditions, the AB 2 -type monomers were formed dominantly during the initial reaction stage. Without any purification, the AB 2 intermediate was subjected to further polymerization in the presence (or absence) of an initiator, to prepare the hyperbranched polymer-bearing multihydroxyl end-groups. The influence of mono- mer, initiator, and solvent on polymerization and the molecular weight (MW) of the resultant polymers was studied thoroughly. The MALDI–TOF MS of the polymers indicated that the polymerization proceeded in the proposed way. Analyses of 1 H NMR and 13 C NMR spectra revealed the branched structures of the polymers obtained. These polymers exhibit high-moderate MWs and broad MW distributions determined by gel permeation chromatography (GPC) in combination with triple detectors, including refractive index, light scattering, and viscosity detectors. In addi- tion, the examination of the solution behavior of these polymers showed that the val- ues of intrinsic viscosity [g] and the Mark–Houwink exponent a were remarkably lower compared with their linear analogs, because of their branched nature. V V C 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4309–4321, 2007 Keywords: gel permeation chromatography (GPC); hyperbranched; MALDI; Michael addition polymerization; poly(ether aimide)s INTRODUCTION Dendrimers and hyperbranched polymers (HBP), together classified as dendritic polymers, have attracted considerable and increasing attention in recent years. 1 In contrast to dendrimers, HBP have imperfectly branched structures. 2 However, they still inherit the desirable properties similar to dendrimers, such as three-dimensional globu- lar architecture, low viscosity, good solubility, and abundance of terminal groups. Furthermore, they can be prepared conveniently and cost-effec- tively on a large scale in a one-pot procedure. 3 Therefore, HBP can be used as alternatives to dendrimers for emerging industrial applications. In last decade, a wide range of HBP have been synthesized by diverse synthetic strategies, such as self-polycondensation, 4 ring opening polymer- ization, 5 self-condensation vinyl polymerization, 6 atom transfer radical polymerization, 7 reversible addition fragmentation chain transfer polymer- ization, 8 and other approaches. 9 Correspondence to: Y.-S. Li (E-mail: ysli@ciac.jl.cn) Journal of Polymer Science: Part A: Polymer Chemistry, Vol. 45, 4309–4321 (2007) V V C 2007 Wiley Periodicals, Inc. 4309