Surface studies of ultra-high molecular weight polyethylene irradiated with high-energy pulsed electron beams in air

Effect of nitrogen ion irradiation on the nano-tribological and surface mechanical properties of ultra-high molecular weight polyethylene

“…The formation of chain unsaturations (C;C bonds) represents one of the main effects of the radiation induced chemical changes in polyethylene. Spectra of N 2 + UHMWPE sample display a band at 965 cm − 1 characteristic of trans-vinylene groups and a slight band at 910 cm − 1 typical of vinyl groups [57,62]. A relationship between trans-vinylene yield and crosslinking has been established [62][63][64].…”

“…As expected, post-irradiation oxidation of UHMWPE did not occur and hence the observed changes in mechanical properties are due to the effect of N 2 + irradiation in the absence of oxygen. N 2 + irradiation induces a slight increase in crystalline fraction as reflected by enlargement of the intensities ratio of bands associated with crystalline and amorphous domains (1473 and 1463 cm − 1 ) [57][58][59]. Growth of new crystal lamellae in UHMWPE has been attributed to relaxation of local stresses as a consequence of scission of tie molecules induced by high energy radiations [57,60,61].…”

“…Spectra displayed no detectable bands in the range of 1800-1600 cm − 1 associated with carbonyl groups [57]. As expected, post-irradiation oxidation of UHMWPE did not occur and hence the observed changes in mechanical properties are due to the effect of N 2 + irradiation in the absence of oxygen.…”

“…N 2 + irradiation induces a slight increase in crystalline fraction as reflected by enlargement of the intensities ratio of bands associated with crystalline and amorphous domains (1473 and 1463 cm − 1 ) [57][58][59]. Growth of new crystal lamellae in UHMWPE has been attributed to relaxation of local stresses as a consequence of scission of tie molecules induced by high energy radiations [57,60,61]. It is well known that UHMWPE elastic modulus scales with its crystalline fraction [5,38], so the increase in surface elastic modulus after irradiation can be related to the change in crystallinity.…”

Studies on electron-beam irradiation and plastic deformation of medical-grade ultra-high molecular weight polyethylene

“…On account of these reasons, electron-beam irradiation of thermoplastics, as well as rubbers, has been extensively studied recently (Abdul-Kader et al, 2009;Costa and Bracco, 2004;Costa et al, 2008;Czupryń ska, 2002;Ikada et al, 1999;Khonakdar et al, 2006;Liu and Tsiang, 2002;Sanche, 2003;Sudo" et al, 2004;Tretinnikov et al, 1999;Ż enkiewicz, 2003a, 2003bŻ enkiewicz et al, 2003a, 2003b. It is also known, on the other hand, that the assembly of a metal part of an endoprosthesis in the cup of the polymer acetabulum involves the use of very high squeezing forces.…”