Implantation time dependence of dynamic mechanical properties of irratiated sterilized UHMW-PE hip cups

and a comparison of the properties between non-implanted hip cup sample and non-irratiated block raw sample have been studied. The results suggest that the real part of the young's modulus E' for non-implanted one is higher than that for block raw one

the magnitude of the y relaxation peak decreases and the Tv shifts to higher temperature as a result of crossliking by radiation. With increasing implantation time in vivo condition the mo-dulus E'increase and a relationship

Et=Eo exp (Dtn)

hols

but the magnitude of both in-ternal friction and imaginary part of modulus E'' in γ relaxation transition increase. The cha-ngesin viscoelastic data are interpreted by that the combined chemical and mechanical effects of the body cause a rupture of networks

which inturn causes increase in density of crystalli-nity and a creation of extentive defects within the crystalline and non-crystalline regions of the sample.