The aging behaviors of polyamide were studied by exposure experiments at the four spots in the west and east of China.The mechanical properties decreased with the exposure time.Simultaneity

the cracks were found on the surface pattern.And the degree was different among spots.The effect of moisture and ultraviolet radiation on the mechanical properties and the surface pattern of polyamide were studied.The results indicate that polyamide in west of China deteriorate faster than that in east of China

and the key factor that led to the change of the mechanical properties is the absorbed water and ultraviolet radiation is the main factor that results in cracks in the surfaces of polyamide samples.And the existence of water strengthens the influence of ultraviolet radiation.Therefore

it can be concluded that the ageing of polyamide is accelerated by the ultraviolet radiation and the environmental humidity.