A convenient room temperature polycondensation toward hyperbranched AB₂‐type all‐aromatic polyesters with phenol terminal groups

Abstract

As a convenient alternative to the classical melt polycondensation the one‐pot solution polycondensation of suitable AB2 monomers under mild conditions has been successfully adapted to hyperbranched all‐aromatic polyester with phenol terminal groups. The polymerization was performed in solution at room temperature directly using commercially available 3,5‐dihydroxybenzoic acid as monomer and 4‐(dimethylamino) pyridinium 4‐tosylate as catalyst to suppress the formation of N‐acylurea. Different carbodiimides as coupling agents were investigated to find the optimal esterification conditions. The polymers have been characterized extensively and were compared with their well‐known analogs synthesized in melt. The characterization was carried out by NMR spectroscopy, size exclusion chromatography, and asymmetric flow‐field flow fractionation as an alternative separation technique for multifunctional polymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5158–5168, 2009

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“…Hyperbranched polyesters can be synthesized via various approaches but are most often prepared via AB 2 or A 2 + B 3 type step polymerizations 6–11. The resulting hyperbranched polymers contain hydroxyl and/or carboxylic acid functional groups at the linear and terminal structural units, which are amenable to postpolymerization modification and can be used to tune the thermal, solubility, and mechanical properties of these materials or to prepare core–shell type architectures.…”

Aromatic Hyperbranched Polymers: Synthesis and Application

“…Voit and coworkers [107] performed one-pot solution polycondensation of commercially available 3,5-dihydroxybenzoic acid as AB 2 monomer (Table 1, entry 1), at room temperature in the presence of 4-(dimethylamino) pyridinium-4-tosylate as catalyst to suppress the formation of N-acylurea. Different carbodiimides as coupling agents were investigated to find the optimal esterification conditions.…”

New Epoxy-Anhydride Thermosets Modified with Multiarm Stars with Hyperbranched Polyester Cores and Poly(ϵ-caprolactone) Arms

“…Methyltetrahydrophatalic anhydride (MTHPA), Aradur HY-918 (166 g=mol) and benzyldimethylamine initiator (BDMA), DY 062, from Huntsman were used as received. Two multiarm stars with poly(e-caprolactone) arms and hyperbranched aromatic (Ar-PCL) or aliphatic-aromatic (Alar-PCL) core were previously synthesized by us [16,17] by cationic ring opening polymerization of e-caprolactone from an aromatic or aliphatic-aromatic hyperbranched polyester synthesized following two previously reported procedures [20,21] . The relevant structural parameters and properties of these star polymers are: Alar-PCL: T g ¼ À22 C and T m ¼ 53 C (by DSC).…”