Effects Of Ultra-fine Crystal Powder On Epoxy Resin Adhesive

The rate of shrinkage is relatively high generally when curing epoxy resin adhesives, the internal stress of the cured product is very high relatively because of the rich coefficients of thermal expansion and poor in toughness, so caused low intensity and reliability in practical application because of the high stress. This paper applied ultra-fine crystal powder as filler to join in epoxy resin adhesive to improve and reduce the stress, thereby enhancing the bonding intensive and assurance coefficient in practical application.Preface of the paper introduced the general situation of epoxy resin, crystal powder, the advantages by adding inorganic particles in epoxy resin, mechanism of action on interface and the preparation methods, and the development of epoxy resin adhesives and present researching status, and the existing problems outlined. Finally,introduced the theories of bonding mechanism and the factors of impacting bonding intensive for epoxy resin adhesives.This experiment prepared ultra-fine crystal powder/epoxy resin composite materials by blending, and determined temperature curing process on the basis of large experiment. The particle size of ultra-fine crystal powder is normal distribution and narrow, the size was uniformity. If added it excessive to the epoxy resin matrix, SEM found a large number of agglomerated particle, leading to deteriorate the bonding properties, From the results of XRD testing, adding ultra-fine crystal powder will lead to amorphous phase reduced relatively and without generating new chemical substances on the interface.Thermal expansion coefficients of the composite materials was determined in this paper, it was found that with filler increased, the lower thermal expansion coefficients; It's a linear relationship about the thermal expansion with temperature before Tg, and then lower thermal expansion after started increasing again. Determined the resistance to effect of heat by methods of TG and DSC in this paper, it was found that resistance to effect of heat will decline both after adding ultra-fine crystal powder to epoxy resin adhesives.Tensile strength of the composite materials was tested using universal test machine by national standards in this paper, it was found that with ultra-fine crystal powder filler increased for proper quantities, increased both the tensile strength and tensile elongation; Instead of reducing tensile strength if it's excessive, tensile elongation decreased too, however the young's modulus is continuously increasing.The purpose of this experiment is to improve bonding strength by reduce the internal stress using adding on ultra-fine crystal powder .Shearing strength of composite materials was tested using universal test machine by national standards, through several experiments show that with filler increased for proper quantities, increased shearing strength, but the shear strength will lead to drop sharp if excessive. Finally calculated the internal stress by formula of approximate expression as know as thermal expansion coefficients of epoxy resin, young's modulus and glass transition temperature, thermal expansion coefficients steel plate. The results show that with ultra-fine crystal powder filler increased, the lower internal stress improvement, which increased the tensile shearing strength to some extent in theory, however, the shear strength began to reduce if ultra-fine crystal powder continue to increase, because reduced the content of epoxy resin adhesives relative to filler.