Preparation And Research Of Carbon Material Binders

Carbon materials are widely used in nuke industry and aerospace industries,because they have low density,high specific strength,high specific modulus,high temperature resistance,corrosion resistance,conductive,thermal conductive,and other excellent physical and chemical properties,even in atrocious environment such as high temperature and cold can still maintain a stable performance.However,carbon materials with a large size or complex shape are quite difficult to be fabricated directly due to their brittle character.Therefore,it is crucial to develop an inexpensive and effective connection.Bonding is such a connection,compared with traditional bolt connection,riveting and welding and so on,which cost of product and manufacture is lower,more effective,and the quality is more portable,and its sealing performance and acid alkali resistance are more prominent.Phenol resin was used as the adhesive matrix modified by reinforced materials,carbon boron,in-situ synthesized carbon nanotubes or silica in this paper.We research the property of bonding of the adhesive and analysis the reason of fracture.The contents and conclusion are including:(1)Firstly,silane coupling agent was used as modified agent to improve the dispersion and compatibility between carbon boron and phenol resin.Then,the phenol resin reinforced by modified carbon boron had better bonding strength.When the carbon boron modified by 5wt%silane coupling agent and for 120min,its hydrophobic effect is better.When the mass ratio of modified B4C to PF is 0.75:1,the shear strength of samples is 9.29MPa and 6.86MPa better than the samples reinforced by common B4C of 2.45MPa and natural cracking through 600 ? or 1200 ?.Meanwhile,The retention rate of shear strength is 91.6%though the delta temperature=1200? and five thermal shock resistance.(2)CNTs could be implanted into these pores of the bonded surface,therefore the position of CNTs is relatively stationary and cannot move unconstraint due to the immovable pores of graphite.A riveting structure would be formed between adhesives and graphite by CNTs.CNTs not only reinforce the adhesive matrix,but also improve the interface between the adhesives and graphite by the riveting structure.Meanwhile,The riveting structure could solve the problems of the dispersion and agglomeration of CNTs.The shear strength of bonding samples could be increased by 45.3%compared with the sample without in-situ synthesized CNTs.The retention rate of shear strength is 93.2%through the delta temperature=1200? and five thermal shock resistance.(3)Ttraethoxysilane(TEOS)was used as raw materials and silane coupling agent(3-aminopropyltriethoxysilane)as catalyst and modifier.Silica was synthesized by in-situ in the phenol resin.In this way can dispersion and compatibility be improved between silica and matrix.Meanwhile,the heat resistance and bonding strength could be improved.When the theoretical content of nano-silica,there is an enormous improvement in the shear strength comparing with the pure phenol resin through 1000?.The most shear strength is 3.44MPa.