Preparation And Properties Of Concave-convex Fabric Structure-reinforced Gradient Polyurethane Buffer Sandwich Composites

The single polyurethane cushioning material has poor impact resistance and easier to be teared,which is difficult to meet the wider application.Inspired by sandwich structure composite materials,the sandwich structure cushioning composites with low-cost and high efficiency were constructed with textile structural materials,which could improve the overall impact resistance.The low-cost polyurethane foam was used as the base material of surface layer,SEBS-g-MAH was used as the surface layer polyurethane foam reinforcing filler,the unique concavo-convex fabric structure design which was prepared by spacer fabric and low melting point PET was used as the core layer base material to enhance cushioning property,and combining the interface structure and cell gradient generated by two-step foaming were used to prepare a multi-stage cushioning composite material,which can realize the structural design of low-cost and high-efficiency cushioning composite material.Firstly,the polyurethane foam was used as the base material,SEBS-g-MAH as the reinforcing filler to enhanced gradient cushioning polyurethane composite was prepared by two-step free foaming process.The effects of the interfacial structure,cell gradient,and the amount of SEBS-g-MAH addition on the microstructure,thermal properties,and mechanical properties of the composites were mainly studied.The results show that the interface structure and cell gradient can absorb 56% of the impact energy.On this basis,the addition of SEBS-g-MAH with an appropriate amount can further improve the cushioning property of the composite material,which can absorb 84% of the impact energy.Secondly,the SEBS-g-MAH/concave-convex fabric-reinforced gradient cushioning polyurethane composites were prepared by introducing a concave-convex fabric structure to improve the cushioning property of composites.The effects of the size and space of the spacer fabric in the concave-convex fabric structure on the compressive and cushioning properties of the composite materials are discussed.The results show that the addition of a concave-convex fabric structure can absorb 98% of the impact energy.Furthermore,basis on the optimal size and space of WKSF,the flexible design of the concave-convex fabric structure was used to focus on the effects of different types of warp-knitted spacer fabrics and different lamination methods on the cushioning properties of composite materials.In addition,the ultra-high molecular weight polyethylene fabric was used to enhance the surface of the composite.The results show that composite materials with different concave-convex fabric structure parameters can be applied to cushioning fields with various impact levels,and surface enhancement can further improve the puncture resistance of composite materials.Finally,the theoretical prediction formulas of previous studies were used to predict the compressive and cushioning properties of the SEBS-g-MAH/concave-convex structure-reinforced gradient cushioning polyurethane composites.The results show that the theoretical predictions are highly matched with the experimental test results.This study provides a theoretical basis for the design of subsequent sandwich-like cushioning composite materials.