| With the development of deep-sea technology and global deep-sea strategypropulsion, solid buoyancy materials (SBM) gradually become the focus of attention.Deep-sea solid buoyancy material is a kind of composites, which has lower density,higher strength and lower water absorption rate. The density is a very importantperformance index to solid buoyancy material, and the buoyancy of materials woulddiminish or be lost with the increase of density. For assured higher compressivestrength and safety of materials, hollow glass microsphere/epoxy resin compositematerial is usually utilized.Composite of hollow glass microspheres (HGM) filled Cycloaliphatic Epoxy Resin(ERL-4221) was prepared in the experiment, which had lower density, higher strengthand lower water absorption rate. The density range of composite prepared was0.5-0.7g/cm~3, and the range of compressive strength was40-70MPa, and the waterabsorption rate at room temperature was less than1%.The system of anhydride curing agent methyl tetrahydrophthalic anhydride(MTHPA) cured Cycloaliphatic Epoxy Resin (ERL-4221) had been studied in theexperiment. The curing process was characterized by the DTA-TG analysis and thetemperature of the cured epoxy was further determined using FTIR analysis. Thecompressive strength of epoxy resin samples with different content of curing agent(MTHPA) was tested and the fracture surface of samples was also analysed bySEM.The experimental results indicate that the curing exothermal peak was singleand using step temperature could raise the reaction extent. When mass ratio ofcuring agent and epoxy resin ERL-4221was100:（100-140), compression strengthcould reach150MPa, which satisfied the strengthen requirement of the composite.Curing kinetics of methyl tetrahydrophthalic anhydride (MTHPA) curedCycloaliphatic Epoxy Resin (ERL-4221) was analysed by DSC at different heatingrates. Apparent activation energy of the curing system was calculated using Kissingerand Ozawa method, and the average value was83.519kJ/mol. The reaction series calculated by Crane formula was0.91and the resulting kinetic equation was dα/dt=7.52×10~7exp(﹣8.352×10~4/RT)(1-α). The variety law of the glass transitiontemperature (Tg) with curing temperature and resin formulation was studied by DTAanalysis. The results indicate that curing temperature had a great influence on Tg, andthe value relationship of the four samples which were used the curing conditions（1）120℃/4h（,2）150℃/2h（,3）150℃/4h, and（4）100℃/6h+120℃/2h+150℃/2h was（4）＞（1）＞（2）＞（3）. However, the content of curing agent had lesseffect on Tg.The influence of the content of anhydride and curing catalyst on the compressivestrength of solid buoyancy material was studied. The influence of volume ratio ofhollow glass microspheres (HGM) and epoxy resin on the mechanical properties ofcomposite was also discussed. The results indicate that the content of curing catalysthad an obvious effect on the strength of composites. Composites had a higher strengthwhen the content of curing catalyst was1g/(100g epoxy resin), and the change ofcompressive strength of composites was little when the content of curing agent was100-140g/(100g epoxy resin), and the change was equal to the test error. Meanwhlie,with the increase of content of hollow glass microsphere (HGM), the compressivestrength and the density of composite both significantly decreased, and the waterabsorption rate increased first and then decreased. When the volume ratio of hollowglass microspheres (HGM) and epoxy resin was30:70, and water absorbing was0.2%,the compressive strength of hollow glass microspheres(HGM)/epoxy resin compositewas70MPa and its density was0.64g/cm~3. Finally, according to the SEM anlaysis,the caking power of composite increased with the increase of the content of epoxyresin. |
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