Study On The Erosive Wear Properties Of Nano-Silica/Polyurethanes Co-modified Epoxy Resin

The concrete structure was corrupted by the strong wind with sand all the year around,and due to the influence of other natural factors,the durability of the concrete structure seriously reduces.Therefore,epoxy resin is usually used as a matrix material to protect it.Because of its low market cost,epoxy resin is widely used in the surface protection and repair of concrete structures.However,pure epoxy resin can not be directly applied in practice.Therefore,in the application of engineering protection,the toughening of epoxy resin has become an important topic for researchers to explore.In this thesis,the epoxy resin was toughened by polyurethane tougheners,such as A72,103F and self-made polyurethane,the mechanical properties and erosion wear properties of modified epoxy resin were tested,and the optimum ratio of polyurethane toughening modifiers was obtained by comparison.Then the epoxy resin was modified synergistically by nanometer SiO₂ and polyurethane,and their mechanical properties and erosion wear properties were tested,and the erosion characteristics of the modified epoxy resin were obtained.Finally,the nano-SiO₂/polyurethane co-modified epoxy resin matrix composite was prepared,and its erosion wear property was tested.The feasibility of using SiO₂/polyurethane co-modified epoxy resin matrix composite with different glass-fiber layer direction as protection material for concrete under strong wind sand flow environment was verified.The results of the experiment are as follows:?1?Polyurethane modified epoxy resin.The addition of A72 modifiers severely reduced the strength and hardness of epoxy resin materials,while the addition of polyurethane toughening agent 103F and self-made polyurethane had little effect on the tensile strength of epoxy resins,but increased their impact toughness.In comparison,the enhanced and toughened effect of homemade polyurethane is better.When the amount of self-made polyurethane is 15%,the tensile strength of the epoxy resin is 38.84 MPa,the impact toughness is 1.38 J/cm²,and the Shaw hardness is ranging from 80 to 82.The corrosion resistance of the epoxy resin materials modified by the 103F and the self-made polyurethane has been improved.When the amount of the two tougheners is 15%,the erosion rate is the lowest at each erosion angle.At the 45°erosion angle with the largest erosion rate,the erosion rate of 15%103F modified epoxy resin material decreased by about 27.7%compared with the blank sample,the erosion rate of 15%homemade polyurethane modified epoxy resin material decreased by about 51.1%compared with the blank sample,which showed better erosion resistance.?2?Nano-SiO₂ modified epoxy resin.The addition of a certain amount of nano-SiO₂improves the mechanical properties of epoxy resin materials.When nano-SiO₂ is doped by1%,the tensile strength reaches 38.74 MPa,the impact toughness reaches 1.99 J/cm²,and the Shaw hardness value reaches 80.Nano-SiO₂ modified epoxy resin also showed the erosion law of semi-plastic materials,at the 45°erosion angle with the largest erosion rate,the corrosion resistance of the modified epoxy resin material with 1%nano-SiO₂ was the highest.?3?Nano-SiO₂/Polyurethane collaborative modified epoxy resin.When 1%nano-SiO₂ is co-modified with 15%polyurethane epoxy resin material,its tensile strength does not change much compared with the blank sample,but its impact toughness reaches 2.59 J/cm²,compared with 15%homemade polyurethane modified epoxy resin increased by 87.7%;Nano-SiO₂/polyurethane co-modified epoxy resin also maintains the semi-plastic erosion law,the erosion rate at the 45°erosion angle is the largest;The erosion rate of 1%nano-SiO₂ and15%polyurethane modified epoxy resin material at 45°erosion angle is 0.0335 mm³/g.Compared with its single modified epoxy resin,the erosion rate decreased by 36.3%and36.2%respectively.?4?Fiberglass reinforced epoxy resin matrix composites.The enhancement of 1%nano-SiO₂ and 15%polyurethane modified epoxy resin matrix composites with different paving directions has the highest erosion rate at an erosion angle of 60°.It also shows the erosion law of semi-plastic materials,but the addition of glass fiber cloth increases the brittle orientation of epoxy resin based materials;At each erosion angle,the epoxy resin matrix composite with 0°orientation coating has the best erosion wear resistance.At the angle of erosion of 60°,the erosion rate of the reinforced epoxy resin matrix composite material of the glass fiber cloth with a 0°orientation pavement is 1/46¹/11 of the erosion rate of the M30mortar,C30 concrete,C50 concrete and cement stone.The results show that the composite has good corrosion resistance and is suitable for protection against erosion and wear of concrete structures under strong wind and sand conditions.