Preparation,properties And Application Of Hybrid Fiber Reinforced Polyurethane Composites

Carbon fiber reinforced composite(CFRCs)is gradually replacing the traditional materials with high weight because of its advantages of light weight and high strength.There has been a broad application prospect in the fields of aerospace,automobile,railway,ocean and wind power generation.However,the high cost of carbon fiber reinforced materials limits its wide application and commercialization.Moreover,compared with its excellent tensile properties,the interlaminar shear properties of the composite is very poor.At present,hybrid fiber reinforced composite(HFRCs)is one of the effective ways to provide the possibility of solving these concomitant issues in CFRCs.In this paper,GF and CF were used as hybrid fiber reinforcements,polyurethane as matrix resin,and rod-shaped HFRCs with different hybrid structures were prepared by pultrusion technology.The mechanism of the influence of hybrid structures and interface properties on the mechanical properties and failure mode of hfrcss was studied systematically.The main researches of this paper are as follows:1.The curing kinetic equation of polyurethane was determined by non-isothermal DSC test.The optimal curing temperature of polyurethane was 70.50 ?,and the curing reaction time was 126 min.In addition,the effects of curing temperature(25 ?,50 ?,75 ?,100 ?,125 ?)on the mechanical properties of polyurethane were studied.2.Hybrid fiber reinforced composites with different hybrid structures were prepared by pseudo pultrusion technology.The influence mechanism of hybrid structures on mechanical properties and failure mode of composites was studied.The results show that the tensile properties of HFRCs are between the tensile properties of glass fiber composite and carbon fiber composite,and the interlaminar shear strength of HFRCs is higher than that of glass fiber composite and carbon fiber composite,showing a significant positive hybrid effect.The HFRCs of different hybrid structures have different mechanical properties,among which the HFRCs of concentric hybrid structure have the best tensile properties,the HFRCs of interlaminar hybrid structure have the highest interlaminar shear strength,and the HFRCs of interlaminar hybrid structure have the best comprehensive mechanical properties.3.PVA modified fibers and PVA/GO/OCNTs modified hybrid fibers were prepared by dip coating.The influence of PVA and GO/OCNTs on the surface properties of fibers was investigated.When PVA content is 1.5wt% and GO/OCNTs content is 1wt%,the hybrid coating on HF surface is uniform and dense.The results of HF surface performance analysis show that PVA/GO/OCNTs hybrid coating greatly increases the surface area of fiber,mechanical riveting force and chemical bondi ng force between fiber and matrix resin,which is beneficial to improve the interface performance between fiber and resin.4.An effective polyvinyl alcohol/graphene oxide/oxidized carbon nanotubes/hybrid fibers(PVA/GO/OCNTs-HF)was prepared by using PVA/GO/OCNTs hybrid coating modified hybrid fiber(GF/CF).Compared with carbon fiber composite,The PVA/GO/OCNTs-CF increased the tensile strength and interlaminar shear strength by34.55% and 20.17%,while the PVA/GO/OCNTs-HF increased the tensile strength and interlaminar shear strength of the composite with concentric hybrid structure by 27.98%and 55.23%.The mechanical properties of PVA/GO/OCNTs-HF composites are significantly enhanced by the synergistic effect of the strong interface properties and hybrid structure.