Study on hygro-thermal aging performance of two-component polyurethane sealant

Abstract

Abstract: To improve the hygro-thermal resistance of polyurethane （PU） sealants for high-speed railway， a two-component PU sealant was prepared by using inorganic CaCO3 as a filler， and its mechanical performance， adhesion property， and thermal stability were examined to investigate the performance changes of the sealant after hygro-thermal aging tests. The corresponding aging mechanism was studied by using Fourier-transform infrared spectroscopy and scanning electron microscopy. The results indicated that hygro-thermal aging reduced the tensile strength of the PU sealant， and its elongation at break was enhanced at the initiate aging stage. The CaCO3 filler could inhibit the decay of mechanical properties， adhesion properties and thermal stability for the PU sealant. Microscopic analysis indicated that hygro-thermal aging resulted in the swelling and fracture of the chain segments of the PU sealant， leading to cracks in the PU sealant as well as a decrease in mechanical properties. The incorporation of the CaCO3 filler could prevent the cracks in the PU sealant and therefore improve its hygro-thermal resistance.

Key words: high-speed railway construction, polyurethane, sealant, hygro-thermal aging, mechanical property, adhesion

References

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