Dendritic resins for coating applications

Hyperbranched, aliphatic polyesters of theoretically calculated molar masses 1 200–44 300 (2–7 generations) were synthesized in the molten state from 2, 2‐bis(hydroxymethyl)propionic acid (bis‐MPA) (repeating unit of ABx‐type) and 2‐ethyl‐2‐(hydroxymethyl)‐1, 3‐propanediol (TMP) (core molecule) using acid catalysis. The synthetic procedure was a pseudo‐one‐step divergent reaction. The degree of branching was found to be near 80 %. A study has also been made with respect to the rheological properties of the hyperbranched aliphatic polyesters. The polymers exhibit an almost newtonian behaviour in the molten state. They also exhibit a lower increase in viscosity with molecular weight than linear polymers. The surface functionality is shown to greatly affect the viscosity of the polymers.