New improved thermosets obtained from DGEBA and a hyperbranched poly(ester-amide)

The influence on the curing process of a commercial hydroxy-functionalized hyperbranched poly(ester-amide) (HBP) Hybrane (R) S1200 on diglycidylether of bisphenol A (DGEBA) was studied. By Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR) the curing reaction was studied and the covalent incorporation of the modifier in the matrix was proved. By Thermomechanical Analysis (TMA) the reduction of the contraction after gelation on changing the S1200 proportion was observed. The incorporation of S1200 increased the glass transition temperature (T-g) and reduced the overall shrinkage, specially after gelation. The modified materials were more thermally degradable than neat DGEBA thermosets. Thermal expansion coefficient, Young's modulus, impact strength and micro-hardness were improved without compromising the thermomechanical characteristics. The water uptake behaviour was also evaluated. (C) 2009 Elsevier Ltd. All rights reserved.