The anti-aging properties of two kinds of room-temperature curing polyurethanes foams prepared by chemically grafting hindered phenolic antioxidants (3

5-ditert-butyl-4-hydroxybenzoic acid) and physical blending of pentaerythritol tetrakys 3-(3

5-ditert-butyl-4-hydroxyphenyl) propionate were compared under hydrothermal and dry heat condition. The results show that the initial strength of polyurethane foam grafted hindered phenol antioxidant was 0.31MPa under the condition of hydrothermal aging

and the tensile strength of the material increased to 0.42MPa due to further cross-linking and curing under heating aging conditions after 1 week of aging

and the tensile strength reached 0.40MPa at the age of 52 weeks. The initial strength of the polyurethane foam grafted with hindered phenol antioxidant was 0.31MPa

while the tensile strength of the material reaches 0.38MPa after 4 weeks of aging under dry heat condition

and the tensile strength of the material reaches 0.32MPa after 52 weeks of aging. After 52 weeks of hydrothermal aging

the strength retention rate of the polyurethane foam was 129% with the phenolic antioxidants grafted while 90% with the traditional antioxidants added. The strength reduction rate of both grafted and physically blended polyurethane foams is lower than that of pure polyurethane foams without antioxidants and the anti-aging properties of polyurethane foams grafted with hindered phenol antioxidants was improved significantly.