Co‐catalytic system design for deriving reactive diluent to construct robust benzoxazine resin with microphase‐separated structure

Abstract

AbstractExploitation a facile and effective strategy for preparing benzoxazine resins with outstanding processability and robust mechanical properties still exists a challenge. In this work, a co‐catalytic concept was proposed to fabricate high‐performance benzoxazine resin by employing curing agent to derive reactive diluent to construct microphase‐separated system. Given on the design, the reactive diluent dissolved solid benzoxazine into a low‐viscosity solution, after which the curing agent presented a catalytic effect on diluent and benzoxazine to optimize the curing crosslinking reactions. As a result, it not only increased crosslinking density for a stable mechanical network, but also induced a microphase‐separated structure to effectively dissipate energy for a strong yet tough resin system, as proved by Fourier transform infrared, differential scanning calorimetry, and dynamic mechanical analyses measurements. Moreover, the as‐prepared modified benzoxazine resin showed great potential to fabricated composites with glass fiber, in which the values of tensile strength, elongation at break, and toughness presented an improvement of 212.1%, 106.8%, and 75.0% compared to composite with pristine PH‐ddm and glass fiber, respectively. These results suggested an effective path to improve the processability and overall mechanical properties of benzoxazine resins, opening a new strategy to develop high‐performance benzoxazine materials.