Epoxy-Benzoxazine Powder Binders for Producing Reinforced Composites with a Matrix Gradient

Abstract

Carbon composites with graded binder distribution along the product cross-section were developed using epoxy-benzoxazine powder binders. Their rheological, thermophysical, and physicomechanical properties were analyzed. It was demonstrated that graded compositions offer certain advantages in providing control over the parameters of the production process, both during the plate consolidation and the final product formation by pressing. The production of dry prepregs by electrostatic spraying of powder binders on carbon fiber followed by melting, the consolidation of prepregs into plates by vacuum bagging, and subsequent pressing of the plates to obtain the product were optimized. The feasibility of producing a graded carbon composite with enhanced physicomechanical and thermophysical properties was revealed for powder compositions based on benzoxazine, thermoplastic polymer, and epoxy-novolac and epoxy resins. Binder compositions with a gradient of components were proposed. A positive effect of the matrix gradient on lowering the temperature gradient during thermal pressing was confirmed.

Keywords

• functionally graded composite
• epoxy oligomers
• benzoxazines
• carbon fiber
• carbon fiber reinforced plastic
• rheology
• consolidated plates
• physicomechanical properties