Comparison of two antioxidants for poly(etherurethane urea) in an acceleratedin vitro biodegradation system
✍ Scribed by Schubert, Mark A. ;Wiggins, Michael J. ;Anderson, James M. ;Hiltner, Anne
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 598 KB
- Volume
- 34
- Category
- Article
- ISSN
- 0021-9304
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✦ Synopsis
Vitamin E (±␣-tocopherol) was recently investigated as an antioxidant for implanted poly(etherurethane urea) (PEUU) elastomers. In that work, vitamin E prevented chemical degradation of biaxially strained PEUU up to 5 weeks implantation, and prevented pitting and cracking of the PEUU surface for the duration of the 10-week cage implant study. The promising results of the in vivo studies motivated a detailed comparison of vitamin E with Santowhite, the standard antioxidant used in PEUU elastomers. To evaluate vitamin E and Santowhite as antioxidants in PEUU, an accelerated in vitro treatment system was used that mimics the in vivo degradation of PEUUs. [2][3][4] Vitamin E was even more effective than Santowhite in preventing pitting and cracking to the biaxially strained PEUU elastomers. The inhibition of ether oxidation was greater with vitamin E than with Santowhite when compared by equivalent concentrations and molar concentrations, respectively. It is hypothesized that the increased effectiveness of vitamin E in this system, compared to Santowhite, is due to differences in antioxidant mechanism(s). Vitamin E is more efficient in preventing PEUU oxidation than Santowhite because its phenoxy radical is more stable and it can terminate more than one chain per vitamin E molecule.