Study On The Preparation And Properties Of Spherical Shell Structure Lightweight Resin-based Composite Materials

As the rapid development of marine engineering, aerospace and other fields in recent years,the requirement for lightweight resin-based composite material performance is also increasing.At present, lightweight composite material was usually prepared by filling glass microballoon in resin matrix. The density and strength of lightweight composite material can be adjusted by changing the volume fraction of glass beads. However, this method can not further decrease the density for a given strength.Therefore, the study on the system of spherical shell structure filling with glass beads/ epoxy resin complex had important engineering significance on improving the specific strength of lightweight resin-based composites.In this paper, self-made ES-1 epoxy resin matrix with low-viscosity, methyl tetrahydrophthalic anhydride and 2-ethyl-4-methylimidazole, glass beads and spherical shell were used as matix, curing agent and lightweight filler, respectively, to prepare the perform of lightweight resin-based composite material with 10wt%, 15wt%, 20wt% and 25wt% of glass beads.The optimized proportion of glass beads in the preform of lightweight resin-based composite material was got by evaluating viscosity of preform, the density of preform after solidification and its mechanical property. Then the spherical shells were combined with the optimized preform to prepare lightweight resin-based composite material and analyzed the influence of different spherical shell diameters and wall thickness on the performance.The results showed that as the glass bead increased, the viscosity raised in the preparation process and the density, compression property, bending propertyand tensile property decreased. The viscosity, density, specific compress strength, specific bending strength, and specific tensile property were5578mPa·s, 0.91g/cm3, 117960 N·m/kg, 55246 N-m/kg and 31250 N·m/kg, respectively, when the amount of glass bead was 15wt%, which was suitable as lightweight resin-based composites complex system with spherical shells.The compressing fracture morphology showed the epoxy resin layer between the glass beads thinned, which was caused by the increasing of glass beads, the shear failure of glass beads and the debond of glass beads from epoxy resin commonly led the decreasing of preform mechanical property.According to the closest packing principle, the low-viscosity epoxy resin filled with glass beads was cast in a fixed volume mold containing spherical shells under vacuum condition to prepare lightweight resin-based composite material with spherical shells. The influence of different spherical shell diameters and wall thickness on the its density and compression property was analyzed. The results showed that the performance of lightweight resin-based composite material with spherical shells of 10mm diameter and 0.38mm thickness was best,whose density, compress strength and specific compress strength were 0.572g/cm3, 29.36Mpa and 59399 N-m/kg, respectively. The fracture morphology showed the stress concentrated on the structure of spherical shells under the compressed load, which caused the formation of crack, when the crack extended further, resulting in the material failure.