Affiliations: Graduate School of Engineering, Kyoto University, Kyoto, Japan | Graduate School of Agriculture, Kyoto University, Kyoto, Japan | Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan | Ceramic Physics Laboratory, Kyoto Institute of Technology, Kyoto, Japan
Note: [] Address for correspondence: Prof. Naohide Tomita, Graduate School of Engineering, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501, Japan. Tel.: +81 75 753 9200; Fax: +81 75 771 7286; E-mail: ntomita@iic.kyoto-u.ac.jp.
Abstract: The effects of vitamin E addition on the strain-induced crystallization and molecular chain orientation of ultrahigh molecular weight polyethylene (UHMWPE) were examined in order to clarify the wear mechanism of vitamin E-blended UHMWPE in knee prostheses. The structure changes of vitamin E-blended UHMWPE before and after tensile strain were analyzed by X-ray diffraction, Raman spectroscopy and image correlation method. The vitamin E-blended UHMWPE exhibited lower strain-induced crystallization than virgin UHMWPE but a higher Ic value in Raman spectroscopic analysis. The vitamin E-blended UHMWPE also exhibited a larger percentage of negative areal dilatation under tensile strain. These results suggest that the addition of vitamin E to UHMWPE decreases the strain-induced crystallization and increases the strain-induced orientation of the molecular chains present in the amorphous phase.
