Effect of cross-linking ultrahigh molecular weight polyethylene: Surface molecular orientation and wear characteristics

Molecular orientation at the surface layer of cross-linked ultrahigh molecular weight polyethylene (UHMWPE) has been examined. Molecular orientation has been shown to affect the wear resistance and surface mechanical properties of UHMWPE under biomechanical loading conditions. This study utilizes a nondestructive synchrotron based soft x-ray technique; near edge x-ray absorption fine structure at the carbon K-edge to examine the degree of surface molecular orientation of UHMWPE subjected to various cross-linking/sterilization techniques as a function of stress and wear. UHMWPE samples prepared under gamma irradiation, ethylene-oxide (EtO) treatment, and electron beam irradiation were worn in a wear tester systematically. Results suggest that the cross-linking resists surface orientation when the samples were under tensile and biomechanical stresses. The molecular orientation in the C–C chains in the polymer showed a monotonic decrease with an increase in gamma irradiation dosage levels. EtO sterilized sam...

[1]  L. Pruitt,et al.  The influence of sterilization technique and ageing on the structure and morphology of medical-grade ultrahigh molecular weight polyethylene , 1998, Journal of materials science. Materials in medicine.

[2]  A H Burstein,et al.  Retrieval analysis of total knee prostheses: a method and its application to 48 total condylar prostheses. , 1983, Journal of biomedical materials research.

[3]  C. E. Brion,et al.  K-shell excitation spectra of CO, N2 and O2 , 1980 .

[4]  J. Galante,et al.  Macrophage/particle interactions: effect of size, composition and surface area. , 1994, Journal of biomedical materials research.

[5]  J. Stöhr,et al.  The orientation of Langmuir–Blodgett monolayers using NEXAFS , 1988 .

[6]  J. Genzer,et al.  A direct comparison of surface and bulk chain-relaxation in polystyrene , 2003, The European Physical Journal E : Soft matter.

[7]  S. M. Hsu,et al.  Molecular orientation of ultrahigh molecular weight polyethylene induced by various sliding motions. , 2004, Journal of biomedical materials research. Part B, Applied biomaterials.

[8]  J H Dumbleton,et al.  Mechanistic and Morphological Origins of Ultra-High Molecular Weight Polyethylene Wear Debris in Total Joint Replacement Prostheses , 1996, Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine.

[9]  F. Shen,et al.  Development of an extremely wear‐resistant ultra high molecular weight polythylene for total hip replacements , 1999, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[10]  Harald Ade,et al.  CALIBRATED NEXAFS SPECTRA OF SOME COMMON POLYMERS , 2003 .

[11]  D Dowson,et al.  A comparative joint simulator study of the wear of metal-on-metal and alternative material combinations in hip replacements , 2000, Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine.

[12]  Brian J. Edwards,et al.  Orientation softening in the deformation and wear of ultra-high molecular weight polyethylene , 1997 .

[13]  S. M. Hsu,et al.  Molecular orientation and bonding of monolayer stearicacid on a copper surface prepared in air , 1997 .

[14]  C. Bragdon,et al.  The Importance of Multidirectional Motion on the Wear of Polyethylene , 1996, Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine.