Research On Preparation Of Epoxy Resin/Hollow Glass Bead Compound Foam Materials

With the fast process of human exploring and exploiting ocean, solid buoyancy materials for deep sea gradually play an increasingly important role in marine engineering application field. The low density and high strength are basic material properties for solid buoyancy material used in working in deep sea with the environmental characteristics of large diving depth and high hydrostatic pressure. As a result, the research on high-performance solid buoyancy material, enabling it to possess larger compressive strength and lower density as well as better safe reliability, becomes a research hotspot in this field at present. Since the pure compound foam buoyancy material composited by hollow glass beads and epoxy resin can stay sufficient strength under low-density conditions and be applied to deeper sea depth for its high compressive strength and mass ratio, it receives extensive attention and is researched both at home and abroad.Through the system of hollow glass beads being filled with epoxy resin E-54/DDM(4, 4-diaminodiphenyl-methane), the compound foam material with 0.53g/cm3 density and 44.25 MPa compressive strength was prepared in this paper. With non-isothermal DSC, the solidification process of compound foam material was studied and curing kinetics and glass-transition temperature of compound foam material were analyzed. The material's density and microstructure were also researched. In addition, the influence of modification of hollow glass beads and the content of curing agent, additive amount of diluents, loading level of hollow glass beads on the mechanical property of compound foam material were systematically analyzed. Meanwhile, the compressive strength and its failure mechanism of compound foam material were also analyzed through Turesanyi formula and ANSYS simulated analysis.According to the experiment, in contrast with the epoxy resin E-54/DDM curing system, the starting curing temperature of compound foam material's curing system was advanced by 8-10?, and peak curing temperature by 4-6? because of the addition of hollow glass beads. While the enthalpy change of curing reaction also reduced for stuffing's absorption of heat and the glass-transition temperature of curing system raised by 10?. The composite foam curing kinetics parameters was obtained by n-order reaction model and the autocatalytic model, such as the reaction activation energy Ea, pre-exponential factor A, the reaction order n of n-order reaction model and the reaction order m and n of the autocatalytic model. According to the results of calculation, the n-order response model could not perfectly depict curing reaction kinetics, while autocatalytic model could. However, at the later period of curing reaction, the experiment slightly deviated from the model since the curing reaction was effected by diffusion control.Furthermore, there were air foams in the compound foam material system. When the loading level of beads was below 60%, the content of air foams was low and the difference between compound foam material density and theoretical value was small. When that was above 60%, the content of air foams increased and the difference also became larger. With the addition of coupling agent, the soaking effect of hollow glass beads and epoxy resin was improved and the two were glued better, effectively enhancing the mechanical property of compound foam material and especially the impact property. In the experiment, the compressive performance and bending property were the best and impact property was quite poor when the curing agent ratio was 0.85. The reactive diluent enhanced the compound foam material's toughness and also affected the compressive and bending property. When the addition of reactive diluent was 10%, the mechanical property of the system reached the summit.Through mathematical formula Turesanyi, the strength experiment of compound foam material was fitted, as the formula could better fit the variation trend of compressive strength when adhesion coefficient was 2.12. However, the ANSYS simulated analysis indicated that there was of serious stress concentration inside the compound material system when compressive load was applied outside. Since the stress sustained by hollow glass bead's thin-walls was larger than that by matrix resin, it can be known that the compressive strength of thin-walls is important for that of compound materials. In the compression-damaging experiment, the failure form of samples was mainly shear failure of matrix resin when the loading level of beads was lower; while it turned into the synthesis function of shear failure of matrix resin and cracking beads when the level was higher.