Study On The Dffect Of Al₂O₃Surface Treament On Properties Of Micron-Al₂O₃/EP Resin

In this paper, the superficial treatment of micron Al₂O₃by coupling agent isdiscussed. The above research is based on the effect of Al₂O₃after superficial treatmenton the Al₂O₃/E-51/2,4-EMI system, including its performance and curing process. Theresult of pretreatment is represented by the TGA curve, while the FT-IR is employed toexpress the changes of functional groups in alumina surface after surface modification.The influences of different contents of coupling agent and different hydrolysis pHvalues on the performance of the Al₂O₃/E-51/2,4-EMI system are mainly studied. Theresearch in this paper focus on two aspects: i) the impact of the stretching rate and thecontent of coupling agent on the adhesive strength between Al₂O₃/E-51/2,4-EMIsystem after surface modification and the steel, coupled with the discussion of thetensile breaking mechanism by the observation of fracture; ii) the effect of differenthydrolysis pH values and contents of coupling agent on the damping properties andthermal expansion performance of the system after modification.The study indicates that preferable reaction conditions of micron Al₂O₃superficialtreatment by silane coupling agent KH550are hydrolysis for an hour under pH value6of coupling agent regulated by acetic acid and reaction with micron Al₂O₃for hour.The research shows that the curing process of KH550-micronAl₂O₃/EP system wasan exothermic process and dynamic model for the curing reaction belongs to multi-stepsreactions with consecutive reactions. In the curing process, several reactions took placeand enhanced the solidification effect obviously that active epoxy groups opened andthen generated hydroxyl group with hydrogen in the system, meanwhile the additivereaction of the cyanogens among the system along with the reaction betweenamino-group in the KH550and epoxy groups participated in the curing process.The results demonstrate that the adhesive strength increased with an increase in thestretching rate. For example, the adhesive strength between binding agent and steelincreased to61.8Mpa when the stretching rate was0.8mm/min.Besides, the adhesivestrength got much larger with3%coupling agent. By analyzing the fracture, theadhesive strength depended on both the bond body ontology fracture and interfacialfracture.The hydrolysis pH values and contents of coupling agent had a great influence on the damping properties and thermal expansion performance of the EP/Al₂O₃-KH550system after modification. The results manifest that both the damping properties andthermal expansion performance improved to an extent when3%coupling agent wasadded. In addition, when the hydrolysis pH value was6, the damping properties of theEP/Al₂O₃-KH550system decreased a bit and its thermal expansion coefficient was lessthan that with hydrolysis pH values8and9.