Research On Water Absorbability Of Solid Buoyant Materials

As an important part of modern deep submergence technology,solid buoyancy material has played a more and more important role in ocean engineering.Along with the progress of the exploration and development of the ocean,the requirements for density,water absorption and strength of solid buoyancy materials are increasing.The solid buoyancy material which made of epoxy resin filled with hollow glass beads has excellent performance on those capabilities.It has become the focus of research at home and abroad.In this paper,the solid buoyant materials are made of epoxy resin E-54/DDM and E-54/MeTHPA,which filled with 60%mass fraction hollow glass beads S38HS.The density of it is 0.61g/cm3.And the highest uniaxial compression strength is up to 76.7MPa.In addition,another kind of solid buoyant materials is made with 70%mass fraction hollow glass beads.The density of it is 0.57g/cm3.And the highest uniaxial compression strength is up to 51.0MPa.In order to get the best performance,we adjusted the amount of coupling agent changing the bonding between hollow glass bead and epoxy resin interface.With considering the influence of hydrostatic pressure,The influence of coupling agent on the water absorption and mechanical strength of solid buoyancy material was studied.compared with ED(E-54/DDM)system solid buoyancy material,EM(E-54/MeTHPA)system solid buoyancy material has higher compression strength.With removing the influence factors of the air bubble,the bond degree between the matrix and the filled phase is studied through the Turcsanyi equation.It is found that the EM system solid buoyancy material has better combination between two phases.With the addition of coupling agent,the combination of the two phases is more compact and the compressive strength of the material increases.The maximum compressive strength of the two solid buoyancy materials appear in the presence of 6%coupling agents.The maximum increase of compression strength can be as high as 26%.When the addition of coupling agent is more than 6%,The compressive strength of the material began to decrease.Without adding coupling agent,the strength of the material decreased 5%after water absorption under 45MPa hydrostatic pressure and drying.With adding coupling agent,the strength of the material hold after absorbing water With the addition of coupling agent,The strength after drying decreased at first and then increased.with the Influence of hydrostatic pressure,water absorption of ED and EM epoxy resin increased.Among them,EM epoxy resin has higher water absorption.The ideal water absorption of solid buoyancy material under 45 MPa hydrostatic pressure can be calculated.The ideal water absorption of 60%mass fraction hollow glass beads filled ED solid buoyant material under 45MPa hydrostatic pressure is 0.25%,and the actual water absorption is 0.89%.addition 4%coupling agents the water absorption can reduce to 0.48%.The ideal water absorption of 60%mass fraction hollow glass beads filled EM solid buoyant material under 45MPa hydrostatic pressure is 0.38%,and the actual water absorption is 0.97%.addition 4%coupling agents the water absorption can reduce to 0.42%.According to the Fick second diffusion law,the water absorption coefficient k with different coupling agents can be calculated.The optimum k of d ED solid buoyant material is 0.122.It is 0.114 to ED solid buoyant material.It indicates that the EM solid buoyant material treated by coupling agent has better performance on water resistance.It also reflects that the bonding between two phases of EM system solid buoyant material is better.