Macroradical reaction in ultra-high molecular weight polyethylene in the presence of vitamin E

作者：Jahan M S^*; Walters B M

来源：Radiation Physics and Chemistry, 2011, 80(2): 281-285.

DOI：10.1016/j.radphyschem.2010.07.048

• alpha-Tocopherol
• Vitamin E
• ESR
• UHMWPE
• Free radicals
• Oxygen induced radical

Free radical measurements in compression molded ultra-high molecular weight polyethylene (UHMWPE), which contained vitamin E (alpha-tocopherol (alpha-T)), was performed using electron spin resonance (ESR) technique in air at room temperature following gamma irradiation (25-32 kGy) in N(2). The vitamin E was incorporated into one set of samples by blending UHMWPE resin with vitamin E (1 and 10 wt%), then compression molded into a solid and then irradiated. Another set of samples had vitamin E incorporated into them by diffusing vitamin Eat 100 degrees C for 2 h after irradiation. Compared to a control (with no vitamin E), the vitamin E-containing UHMWPE (alpha-TPE) samples suffered a partial loss of PE radicals, but this loss only occurred during or immediately after irradiation (before exposure to air).
Subsequently, when all blended samples were exposed to air, the remaining radicals in each sample decayed to the well-known OIR, R1 (-(center dot)CH-[CH =CH -](m)-) and R2 ((center dot)OCH-[CH =CH -](m)-) radicals. However, because of the initial loss or partial quenching, alpha-TPE produced a lower concentration of OIR (measured over a four-year period), but no difference was found between 1% and 10% alpha-TPEs. In the diffused alpha-TPE, similar OIR was also found when tested after four months of post-treatment exposure to air.

• 出版日期2011-2