Simultaneous toughening and reinforcing of cyanate ester/benzoxazine resins with improved mechanical and thermal properties by using hyperbranched polyesters

Abstract

Abstract In the present study, the influence of incorporating various amounts of hyperbranched polyester (HBPE) into thermosetting resin blends composed of cyanate ester (CE) and benzoxazine (BOZ) resins was investigated for their structural, morphological, mechanical, and thermal properties. The FTIR spectra revealed that the CE/BOZ resin had reacted with the functional groups of HBPE, and the SEM test confirmed the morphological changes from a smooth surface that was observed for the virgin CE/BOZ resin to a rough surface for the maximum HBPE content. Moreover, the mechanical and thermal properties were found to be pointedly enhanced as we increased the content of HBPE. These remarkable enhancements may be due to the chemical structure of the HBPE which could form a cross-linked structure through a strong hydrogen bonding with the CE/BOZ resin. As a result, a considerable amount of applied mechanical load can be absorbed, and in parallel, the thermal stability can also be improved. We believe that the HBPE can be a good toughener for the CE/BOZ resins that could possibly expand their range of applications in various industrial sectors.