KINETICS OF FORMATION OF HYPERBRANCHED POLYESTERS BASED ON 2,2-BIS(METHYLOL)PROPIONIC ACID

The aim of this study was to gain information on the influence of the core moiety on the kinetics of the synthesis of hyperbranched polyeste rs based on 2,2-bis(methylol)propionic acid (bis-MPA). Bis-MPA was est erified in the melt using sulfuric acid as a catalyst, yielding a high ly polydisperse polyester. Bis-MPA was also esterified with different polyols as core moieties. The parameters varied were polyol structure, reaction temperature, and amount of added catalyst. A stoichiometry o f 1:1 for carboxylic- and hydroxyl groups on the polyol was used. The reaction rates were found to be strongly dependent of the miscibility of bis-MPA and the polyol. Higher concentrations of catalyst lead to h igher rates of reaction. Tris(methylol)propane (TMP) and bis-MPA exhib ited the highest rate of reaction, which is due to the low melting poi nt of TMP and good solubility of bis-MPA in the TMP melt.