Preparation and structural characterization of polyurethane modified epoxy structural adhesive
|School||Central South University|
|Keywords||Structural Adhesives Polyurethane Epoxy resin Interpenetrating polymer network|
Papers TDE-85 epoxy resin and E-51 epoxy resin blends mixed epoxy matrix, selection of polyurethane (PU) and epoxy resin (EP), the formation of interpenetrating polymer network (IPN) of epoxy toughened, prepared a 150 ° C curing high temperature epoxy structural adhesive. PU / EP IPN system is determined by differential scanning calorimetry analysis curing conditions, and PU / EP IPN system curing kinetics were studied; infrared spectroscopy to characterize the structure of PU / EP IPN system, discusses the polyurethane modified epoxy resin reaction mechanism; through a scanning electron microscope (SEM) analysis of the impact fracture, PU / EP IPN material two-phase compatibility and morphology; PU / EP IPN materials by thermal gravimetric analysis thermal stability. Use of electronic universal testing machine measurement of polyurethane modified epoxy structural adhesive tensile shear strength at room temperature, 160 ° C high temperature tensile shear strength and peel strength at room temperature, composition of the epoxy structural adhesive component and add the amount to be optimized. . The results show that: PU / EP of IPN systems activation energy of 69.18KJ/mol, the reaction order of 0.901. Urethane-modified epoxy resin system, there are three reactions, namely the reaction of the polyurethane prepolymer and the chain extender 1,4-butanediol, the chemical crosslinking reaction of the polyurethane prepolymer with an epoxy resin, an epoxy resin and mixed aryl curing reaction of the amine curing agent, curing system response final polymer raw transaction networking; With the PU / EP increases the PU / EP IPN surface morphology of bicontinuous phase structure by the island structure; epoxy resin by polyurethane change resistance, mechanical properties sharply rising trend, PU / EP IPN material mechanical properties were increased and then decreased with the increase in the amount of polyurethane add; the IPN material in the PU / EP interpenetrating degree of thermal stability of the low-temperature range and PU / EP IPN material related. Amount of amine curing agent to be added in the polyurethane added amount and mixed aryl, respectively 30% and 33% of the mass of epoxy, urethane-modified epoxy resin adhesive optimal performance. Final preparation of the urethane-modified epoxy structural adhesives, room temperature tensile shear strength 25.81Mpa, a high temperature of 160 ° C the tensile shear strength of 12.85Mpa, the peel strength of 51.68N/cm able to meet the requirements of the use of high temperature structural adhesives .