Preparation And Properties Of The High-performance Solid Buoyancy Materials

With the depth exploration of marine resources of humans and the optimization of marine exploration equipments, solid buoyancy materials are becoming the focus of the study, and the syntactic foam materials which is synthesized by hollow glass microspheres (HGMs) filled in epoxy resin matrix is used as solid buoyancy materials because of its low density and high strength.For solid buoyancy materials used as deep-sea operations, have to withstand a certain hydrostatic pressure, while also has a very small density and moisture absorption, however the typically methods to obtain the small density and moisture absorption is by increasing the volume fraction of HGMs. High volume fraction (volume fraction of 65% to 70%) of syntactic foam was synthesized by vacuum squeeze moulding technique on the basis of previous studies. And the regularity of the relationship between structure and properties was explored. And then, the syntactic foam with volume fraction of 68% of HGMs was processed by artificial pore-forming, so that the density was reduced under the additional performance almost unchanged. What’s more, the performance of artificial-pore materials were analyzed, meanwhile, the expected performance of the actual pore-forming materials were analyzed and summarized.In this paper, HGMs (density of 0.42g/cm3, compressive strength of 55.2MPa) was used as a lightweight filler, then syntactic foam with volume fraction of 65%-70% of HGMs in epoxy resin matrix was synthesized by vacuum assisted molded forming under pressure of 6MPa. When the volume fraction of HGMs was from 67% to 69%, the density of syntactic foam could be effectively reduced the density in the case of the less reduces of the other performances of the materials, and the moisture absorption was substantially less than 1%. However, when the volume fraction of HGMs is 70%, all performances of syntactic foam significantly decreased. Due to the decrease of the volume fraction of epoxy resin, the microstructure of syntactic foam and the stress state of HGMs were changed. So the performance of syntactic foam which synthesized by high volume fraction of HGMs filled epoxy composite foams was changed.Furthermore, the syntactic foam with volume fraction of 68% of HGMs was researched. The density of the materials was reduced by artificial pore-forming. The influence of r/d, the ratio of pore radius r and a, distance between pore bottom and the bottom surface under pressure of the specimen, on the density, moisture absorption properties and resistance to hydrostatic pressure of syntactic foam was explored. And the expected performance of the actual artificial-pore materials were analyzed and summarized. To some extent, density of the materials could be reduced by artificial pore-forming. When r/d was 2/3,1/2 and 1/3, respectively, the density of artificial-pore syntactic foam was decreased. However, r/d was 1/4 and 1/5, respectively, the density of artificial-pore syntactic foam was not reduced but increased. When r/d was 2/3 and 1/2, respectively, artificial-pore syntactic foam can withstand hydrostatic pressure of 60MPa or less. However, the hydrostatic pressure performance of artificial-pore syntactic foam of r/d of 1/3 can withstand hydrostatic pressure of 75MPa after hydrostatic pressure of 45-80MPa for 24h. The design drawing with a simple cubic lattice arrangement of artificial pore was constructed after the analysis on the performance of artificial-pore materials. The performance of the design is explored in theoretically. What’s more, compared with the syntactic foam which was synthesized by HGMs directly, artificial-pore materials could withstand higher hydrostatic pressure under achieved the same density.