HYDROXYL-FUNCTIONALIZED HYPERBRANCHED ALIPHATIC POLYESTERS BASED ON 1,1,1-TRIS(HYDROXYMETHYL)PROPANE (TMP) AS A CORE MOLECULE: SYNTHESIS AND CHARACTERIZATION

The aim of this study is to synthesize and characterize the new hydroxyl-functionalized hyperbranched aliphatic polyesters with various generations for potential use in cancer therapy as targeted drug delivery system. For this purpose, a series of novel hydroxyl-functionalized hyperbranched aliphatic polyesters (HBPs) based on 2,2-bis(hydroxymethyl) butyric acid (Bis-HBA) as AB2-type monomer and 1,1,1-tris(hydroxymethyl) propane (TMP) as B3 core molecule were synthesized via acid catalyzed polyesterification reaction in three different generations and named as HBP-2G, HBP-4G and HBP-5G. The synthesis route was a simple pseudo-one-step reaction where AB2-type monomer and B3 core molecule are polycondensed in the presence of an acid catalyst. The chemical structures of the synthesized HBPs were confirmed by FTIR, C-13 NMR and H-1 NMR analysis. The degree of branching (DB) of the HBPs as calculated from H-1 NMR results were between 0.87 and 0.92. These results showed that all synthesized HBPs had a high degree of branching. TGA measurements exhibited that all of HBPs had similar and good thermal stability. Glass transition temperatures (Tg) of samples were identified using DSC analysis and were found to be between 66.2 degrees C and 69.1 degrees C. Low generation HBPs have considerably higher solubility in organic solvents than high generation HBPs. All synthesized HBPs displayed extremely low water solubility but extremely high solubility in dimethyl sulfoxide. It was concluded that new HBPs which were synthesized in this study have reasonable characteristics for hyperbranched polymers applications