Novel epoxy-anhydride thermosets modified with a hyperbranched polyester as toughness enhancer. I. Kinetics study

A hyperbranched polyester (Boltorn™ H30) has been modified in order to partially replace the terminal hydroxyl groups with aliphatic vinyl chains. This novel hyperbranched polymer (HBP) has been used as a modifier of epoxy-anhydride thermosets with the purpose of enhancing the fracture toughness. The curing kinetics of the neat and the modified formulations have been studied in detail with DSC and FTIR. Model-free and model-fitting kinetic methods have been applied to DSC data to determine the kinetic parameters. The curing mechanism has been elucidated with FTIR. Incorporation of the HBP into the thermoset matrix is assured by the reaction of remaining hydroxyl groups.

► A consistent combination of model-free and model-fitting methods is used.
► The curing mechanism of epoxy-anhydride thermosets is elucidated using FTIR.
► An accelerative effect of hydroxyl-terminated hyperbranched polymers (HBPs) is observed.
► Incorporation and chemical compatibility of the HBP with the matrix is ensured by the reaction of the HBP end hydroxyl groups.