| In this research,the polypropylene glycol(PPG) and toluene diisocyanate(TDI) were selected as raw materials,and the polyurethane prepolymer was synthesized.Then the epoxy resin modified polyurethane composite adhesive were prepared by mixing epoxy resin and adding milled glass fiber or nano—meter SiO2.The mechanical property of modified polyurethane adhesive was studied by the tensile shearing test,tensile test,and impact test.The influence factors of mechanical property were discussed which contained the polypropylene glycol type,the epoxy resin type,contends of epoxy resin and contends of filler.The scanning electron microscopy(SEM) was applied to analyze the dispertion of filler and the fracture failure of composite adhesive.The structure and microtopography of modified polyurethane adhesive were characterized by Infrared(IR) and the reaction mechanisms of epoxy resin modifying polyurethane adhesive were discussed.The thermal performance of modified polyurethane adhesive was analyzed by differential scanning calorimetry(DSC) and thermo gravimetric(TG).The results of studies were such as follow:①The cmechanical property of modified polyurethane adhesive was best which prepared by polypropylene glycol which molecular-weight was 1000(PPG210) and diglycidy 1-4,5-epoxycyclohexane-1,2-dicarboxylate(TDE-85).②The uniform macroface and dissociative micro phase were produced by epoxy group and isocyanategroup reacting.The thermal performance of composite adhesive was increased.When the TDE-85 contents of composite adhesive was 40wt%,the tensile shearing strength tensile strength,impact test strength of modified polyurethane adhesive was 9.98MPa,29.77MPa and 18.34kJ/m2.③By adding milled glass fiber,the mechanical properties of composite adhesive were improved and the water resistant performance of composite adhesive was decreased.When the mass fraction of milled glass fiber was 15wt%,the tensile shearing strength,tensile strength and impact strength of the composite adhesive was 16.15MPa,45.45MPa and 26.11kJ/m2.The dispertion of milled glass fiber was good and the milled glass fiber and the resin cross-linked tightly.④By adding nano-meter SiO2,the mechanical properties,the thermal performance and the water resistant performance of composite adhesive was increased.When the mass fraction of nano-meter SiO2 was 2wt%,the tensile shearing strength,tensile strength and impact strength of the composite adhesive was 15.00MPa,40.06MPa and 26.05kJ/m2.The fracture of composite adhesive was initiated by micro crack. |
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