An Easy Strategy for the Synthesis of Well‐Defined Aliphatic‐Aromatic Hyperbranched Polyesters

Abstract

A one‐pot solution polymerization under mild conditions was adapted for the synthesis of well‐defined aliphatic‐aromatic polyesters with different degrees of branching. The esterification was performed at room temperature using 4,4‐bis(4′‐hydroxyphenyl)valeric acid (AB2) and 3‐(4‐hydroxyphenyl)propionic acid (AB) as monomers. DPTS was used as a catalyst and DCC as a coupling agent. Polyesters with statistical, dendritic topology, controlled degree of branching and $\overline M _{\rm w}$ > 35 000 g · mol−1 were obtained. The polymers were characterized by 1H and 13C NMR, SEC, DSC, and TGA. A strong dependence of the degree of branching and the thermal properties of the polymers depending on the AB/AB2 monomer ratio was observed.magnified image

The Effect of the Degree of Branching in Hyperbranched Polyesters Used as Reactive Modifiers in Epoxy Thermosets

“…The DB was calculated by 13 C NMR spectroscopy as detailed in a previous publication. [16] The different proportions of hydroxyl and ester functions in the HBP structure and their differences in viscosity should influence the curing evolution and the material characteristics.…”

“…[16] In a 500 mL two-necked roundbottom flask, 50 g (1 equiv.) of 4,4-bis(4-hydroxyphenyl) valeric acid and 7.64 g (0.2 equiv.)…”

“…[16] According to the desired AB 2 / AB-ratio in the copolyester, 4,4-bis(4-hydroxyphenyl)valeric acid (AB 2 -monomer), 3-(4-hydroxyphenyl) propionic acid (AB-monomer), and DPTS were dissolved in 15 mL dry DMF. After 30 min, DCC was added and stirred at room temperature for a further 40 h. The Scheme 1.…”

Aromatic Hyperbranched Polymers: Synthesis and Application

“…A one-pot solution polymerization was performed at room temperature using partially aromatic monomers, namely 4,4-bis(4 0 -hydroxyphenyl)valeric acid as AB 2 and 3-(4-hydroxyphenyl)propionic acid as AB [118] (see Table 1, entry 5 for monomer combination), in the presence of 4-(N,N dimethylamino) pyridinium 4-tosylate (DPTS) as catalyst and dicyclohexylcarbodiimide (DCC). The dependencies of the DB and the thermal properties of the polymers on the AB:AB 2 monomer ratio were studied.…”

Influence of end groups in hyperbranched polyesters used as modifiers in the characteristics of epoxy thermosets cured by adipic dihydrazide

“…The HBP-OH ( Figure 1) was synthesized according to a previously described procedure [19] from 4,4-bis(4-hydroxyphenyl) valeric acid as AB 2 monomer. The 1 H and 13 C NMR data are in accordance with those published [20].…”