Biodegradable Hyperbranched Aliphatic Polyesters Derived from Pentaerythritol

Abstract

Pentaerythritol (PENT) was polycondensed with dimethyl sebacate (DMS) in bulk at 240 °C. With Ti(OBu)4 as the catalyst, an equimolar feed ratio resulted in gelation even when no vacuum was applied. When the PENT/DMS ratio was raised to 1.2/1.0, soluble viscous resins were obtained, but despite the excess of PENT, the conversion of methyl ester groups never exceeded 92%. With bismuth(III) n-hexanoate (BiHex3) as the catalyst and an 1.0/1.0 feed ratio, nonviscous polyesters were obtained with conversions <75%. When BiHex3 was used in the beginning and Ti(OBu)4 was added at a later stage, soluble viscous resins were obtained even at 1.0/1.0 feed ratio. Further polycondensations were conducted with higher PENT/DMS ratios. The reaction products were characterized by viscosity measurements, 1H NMR spectroscopy, and MALDI-TOF mass spectrometry. These measurements indicated the formation of hyperbranched polyesters almost free of cycles and ether groups. Furthermore, acylations with acetic or methacrylic anhydride were studied and quantitative conversions of the CH2OH groups were achieved.

Bio‐based Biodegradable and Biocompatible Hyperbranched Polyurethane: A Scaffold for Tissue Engineering

“…The 1 H NMR spectral (Figure 1c) analysis of HBPU with MG in its backbone confirmed the formation of a bio‐based HBPU architecture and indicated the formation of linear, dendritic, and terminal units in the hyperbranched structure. The peaks at δ 4.04, 4.01, 4.00, and 3.98 are due to the presence of tetra‐, tri‐, di‐, and mono‐substituted pentaerythritol, respectively 29. The branching is generated when the integration ratio of substituted –OH to unsubstituted –OH of pentaerythritol moiety is greater than two.…”

Synthesis and characterization of a novel aliphatic polyester based on itaconic acid

“…As to the synthesis of polyesters, TBT was found to be an effective catalyst both in esterification and polycondensation process . Figure shows the dependence of TBT content on the esterification ratio and intrinsic viscosity of PBMS as the BDO/MSA feed molar ratio is 1.08.…”

Hyperbranched Polymers with Controllable Topologies for Drug Delivery

“…describe the synthesis of A 2 +B 4 ‐type hyperbranched poly(β‐amino ester)s through Michael addition of A 2 monomer M7 and B 4 monomer M13 (Table ). Kricheldorf and co‐workers synthesis A 2 +B 4 ‐type hyperbranched polyesters by esterification of M8/M14 and M9/M15 . Aside from A 2 +B 4 ‐type hyperbranched polyimides, polyarylates and polytriazoles can also be synthesized from the copolymerization of M10/M16, M11/M17, and M12/M18 .…”

“…Kricheldorf and co-workers synthesis A 2 + B 4 -type hyperbranched polyesters by esterification of M8/M14 and M9/M15. [26,27] Aside from A 2 + B 4 -type hyperbranched polyimides, polyarylatesa nd polytriazoles can also be synthesized from the copolymerization of M10/M16, M11/M17, and M12/M18. [28][29][30] However,f or n > 4, the construction of the A 2 + B n -type hyperbranched topology is rare, because the molecular weight cannotb ee asily increased before gelation occurs.…”