Investigation of the Mechanical Properties of Three-Dimensional Polyurethane Composites Reinforced with Warp-Knitted Spacer Fabrics

In this study, a novel composite having a unique three-dimensional structure was investigated. Warp-knitted spacer fabrics with glass fiber woven fabric were chosen as the reinforcement, while polyurethane foam was used as the matrix materials. The glass fiber woven fabric was pretreated with the warp-knitted spacer fabric first, and then a hand lay-up method was used to fabricate the three-dimensional polyurethane-based composites. The mechanical properties of the finished composites were determined. The influence of the fabric thickness, the surface structure of the fabric, and whether the woven fabric is laminated or not on the mechanical properties of the three-dimensional polyurethane composites were determined. The results show that the fabric thickness is positively related to the tensile and compressive properties and inversely related to the bending properties of the three-dimensional knitted/woven hybrid polyurethane matrix composites, provided that the surface structure is the same. The tensile and compressive strengths of the composites were higher when the glass fiber woven fabric was laminated with the spacer fabric than when the three-dimensional knitted/woven hybrid polyurethane matrix composites were not taken. Therefore, the knitted/woven fabric as reinforcement improved the tensile and compressive properties of the composites.