writer：Sipei Zhao, Shuiquan Li, Huihui Liu, Jin Jiang, Meichen Wang, Haolang Liu, Weiwei Wang, Zhi Wang
keywords：Polybenzoxazine · Toughening · Quadruple hydrogen bonds
source：期刊
specific source：Advanced Composites and Hybrid Materials
Issue time：2022年

As a new thermosetting resin, polybenzoxazine has attracted extensive attention because of its excellent properties. However, the biggest challenge of polybenzoxazine is the balance among impact strength, thermal stability, and processability. In this work, we frst introduced a 2-ureido-4[1H]-pyrimidone (UPy, containing quadruple hydrogen bonds) dimer into benzoxazine to tackle this challenge. In the blends containing 3 wt% UPy, its toughness and thermal properties have been simultaneously improved, while maintaining a high modulus and a negligible increasement in viscosity. The impact strength and the glass transition temperature (Tg) reach 16.39 kJ·m?2 and 221 °C, which are 172% and 10 °C higher than that of polybenzoxazine, respectively. Meanwhile, this strategy was extended to carbon fber surface modifcation to enhance the interfacial adhesion between fbers and resins. The mechanical properties of modifed fber composites are signifcantly improved. Furthermore, we frstly designed the cyclic fexural experiment of material and tried to propose an efective method to verify the efect of hydrogen bond dynamics on fexural properties of polybenzoxazine. Here, we not only provide a new way to get a balance among diferent properties of polybenzoxazine but also give a broad insight on the application of additional hydrogen bonds

in thermoset resins.