Synthesis And Properties Of The Halogen-Free Flame Retardant Epoxy Resin Construction Structural Adhesive

Construction structural adhesive, as a kind of adhesive, is widely used in reinforcement repairing and sealing for building, bridge and highway. It has got a broad concern in the field for the advantage of convenience operation and good cohesiveness. As a main resin of construction structural adhesive, epoxy resin play a significant role in the construction market because of its good properties. In the applications, if epoxy resin construction structural adhesive could be imparted halogen-free flame retardance while possessing high mechanical property, thermal property and cohesiveness, it would realize the value of high energy, functional and greening.In this paper, P-THD was synthesized, which the flame retardant element P was contained on the THD, and represented by infrared spectrum. In the meantime, with the addition of ATH and red phosphorus, the halogen-free FR epoxy resin construction structural adhesive was prepared. According to the test and analysis of the gel time and cohesiveness, the process conditions were defined as follows, preheating temperature23℃, after62minutes of reaction (THD:P-THD=2:1), the gel phase was got and injected into the mode to solidify48hours at23℃. The universal testing machine, thermal deformation tester, scanning electron microscope, TGA and oxygen index detector were used to test the cohesiveness, thermal property, microcosmic performance, thermal stability and flame retardant property. The effects of different components’usage on several properties of halogen-free FR epoxy resin construction structural adhesive were studied. The result shows that, the cohesiveness first increase and then decrease with the increase of the curing agent. The maximum augmenter percentage is29.67%. And the tensile strength shows an increasing trend first and then decreasing trend with the increase of nano silicon oxide usage and the decrease of cement usage. The peak is37.42MPa, and has an increase of23.98MPa. The Thermal deformation strength, bending strength and compressive strength increase accordingly, which has an increase of8.6℃,33.64%and0.20times respectively. The micro morphology showed flaky texture. And thermal stability and flame retardant property were improved with the increase of ATH and red phosphorus usage, the maximum mass loss rate was less than0.35%, flame retardant level was FV-0class, oxygen index increased by9.54%. The usage and type of the curing agents, flexibilizer, filler and fire retardant was optimized as following, curing agent38phr, flexibilizer40phr, nano silicon oxide28phr, cement12phr, ATH40phr, red phosphorus12phr. And at this time, the carbon residue quantity was greater than45%and oxygen index was29.57%.Compared with construction structural adhesive at home and abroad, the halogen-free FR epoxy resin construction structural adhesive synthesized by ourselves has much better elongation at break, modulus of elasticity, compressive strength, shear strength between steel and steel, and obtains some improvement in tensile strength, bending strength and distortion temperature. At the same time, gel time is suitable for practicing operation and the curing could be finished at room temperature.