A Novel additive manufacturing process for multi-matrix fiber reinforced composites

Integrating different matrices into fiber-reinforced plastics (FRP) offers great potential for general tailored functionalities. By locally integrating flexible matrix zones in otherwise stiff FRPs, both very stiff and flexible areas with properties such as bending and damping behavior can be achieved. A novel method for manufacturing these so-called multi-matrix composites (MMC) is presented in this work. Either manually or in an automated fashion a first matrix system is locally applied to fiber preforms. After curing these zones, all fiber areas that are still dry can be infiltrated with a second matrix system. In this manner a composite structure with different and defined matrix zones of almost any size and shape can be created. Experimentally, the integration of flexible polyurethane and stiff epoxy resin into glass fiber preforms was investigated, considering material compatibility and process precision. For an established process-chain, good infiltration quality with distinct transition zone between the matrices was verified, resulting in bending specimens showing deformation only in the regions of polyurethane elastomer matrix.