| As one of the fast developed polyurethane products, polyurethane adhesives（PU） had become the most important adhesives in the field of composite flexiblepackaging. It was divided into solvent-based, water-soluble and solvent-freetypes. Because of energy consumption, environmental protection and otheradvantages, alcohol-based two-component polyurethane adhesives （APU） hadreceived researcher’s more attention. But the performance of APU adhesives wasnot as good as the ester dissolved polyurethane （EPU） adhesives, which limitedthe application scope of APU adhesives. In order to enhance the performance ofthe APU, nano-SiO2was added into APU in the experiment. SiO2particles wereeasy to reunite, compatibility with the PU matrix was poor, therefore, the SiO2surface was modified by different methods.In this passage, the surface of nano-SiO2was treated by KH550, KH560,KH570and TDI respectively. Such kinds of SiO2were dispersed in polyetherglycol by ultrasound equipment, after reacting with TDI,-NCO terminatedprepolymer was obtained. Diethylenetriamine as chain extender, schiff basetechnology was applied for reaction,-NH2terminated PU was obtained. Afterreacting with hardener E51, alcohol-soluble nano-SiO2/polyurethane adhesiveswere obtained, the properties of adhesives were tested.FT-IR results showed that: TDI and three kind of coupling agent graftedonto the SiO2,-NCO groups of TDI all participated in the reaction and formed-NHCO-structure in the synthesis process, PU and E51was cured thoroughly.The SEM results showed that: modification can weaken the agglomeration ofSiO2and improved the dispersion of SiO2in the PU. TEM results showed thatsurface of the SiO2coated with the modifier. XRD results showed that: aftergrafting modifiers, the crystal structure of the SiO2was unchanged essentially,and after adding SiO2, micro-phase separation of the PU can be enhanced slightly. AFM results proved that: after grafting different modifier, the dispersion heightof the SiO2was different in the PU. DMA results showed: after adding SiO2,storage modulus, loss modulus, loss factor of the PU were increased. Theexperimental results showed that: mass fraction of the SiO2that was modifiedseparately by KH550, KH560, KH570was3wt%, the mass fraction of the SiO2that was modified by TDI was4wt%, the performance of SiO2/PU adhesives wasbest, the shear strength of SiO2/PU adhesives was improved by8.61%,9.81%,9.10%,13.87%, the tensile strength of SiO2/PU adhesives was improved by20.03%,22.39%,21.48%,26.56%, the breaking elongation of SiO2/PU adhesiveswas improved by24.22%,25.15%,23.33%,33.25%, the water absorption ofSiO2/PU adhesives was decreased by15.88%,17.06%,14.7%,18.68%. |
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