Study On Low Temperature Properties Of Modified Epoxy Resin

Composite material occupies an extremely important position in national economic development,it has been widely used in aerospace,Marine and other fields.But when we use the resin matrix composites in a low temperature environment,it will have many problems,such as high brittleness and easy to crack,which greatly limits the application of resin matrix composites in low temperature environment.Some cold regions such as north and south poles,stored a lot of resources,so it is important to develop the resin matrix composite used in the polar cold region.This paper committed to develop an resin matrix composite which has a good mechanical properties at low temperature.We selected E51 epoxy resin as matrix,PPGDGE as toughening modifier,negative thermal expansion ZrW2O8 powder as strengthening agent.We studied the influence of the mass fraction of PPGDGE in the mechanical properties of the composites and the viscosity of the resin.We also studied the Synthesis process of the ZrW2O8 powder,and the influence of the mass fraction of ZrW2O8 powder in the mechanical properties of the composites and the density of the composites.Then we use the SEM to observe and analyze the section of the material.During the research,we made this modified resin by mixing toughening modifier with E51 epoxy resin.The results show that the best mass fraction of PPGDGE is 20wt%,at room temperature,the tensile fracture strain of the material reached 7.5%,which is 82.9%higher than that before the modification,the tensile strength of the material is 93.3MPa,the compression strength is 129.8MPa,the bending strength is 116.60MPa.At low temperature,tensile fracture strain of the material reached 5.4%,which is 50%higher than that before the modification,the tensile strength of the material is 130.4MPa,compression strength is 174.6MPa,bending strength is 154.9MPa.The viscosity of the resin at 60 ? is 533.3mPa-s.We use the zirconium dinitrate oxide and ammonium tungstate hydrate as raw materials to prepare rod-like negative thermal expansion ZrW2O8 powder by hydrothermal synthesis.By using TG-DTA,XRD and SEM to test the ZrW2O8 powder,we figure out the best molar ratio of Zr4+ to W6+ is 1.2:2,the best hydrochloric acid concentration is 6mol/L,the best heat treatment temperature is 570?.The ZrW2O8 powder obtained by the above-mentioned process is high purity a-ZrW2O8 powder,the particle size is about 600nm × 450nm × 5?m,and the surface of the ZrW2O8 powder is smooth,the size is more uniform,the grain shape is more complete,so this ZrW2O8 powder is suitable as resin reinforcement.The ZrW2O8 powder was used to prepare composite materials,by mixed with modified resin.The results show that the best mass fraction of ZrW2O8 powder is 5wt%,at room temperature,the tensile fracture strain of composite reached 7.1%,the tensile strength of composite is 110.3MPa,compression strength is 161.1 MPa,bending strength is 138.2MPa.At low temperature,the tensile fracture strain of composite is 5.6%,the tensile strength of composite is 146.2MPa,compression strength is 199.7MPa,bending strength is 171.2MPa.When the mass fraction of ZrW2O8 powder is 5wt%,the bulk density of composite is 1.33g/cm3.