Long term in vitro biostability of segmented polyisobutylene-based thermoplastic polyurethanes.

Abstract

Long term in vitro biostability of thermoplastic polyurethanes (TPUs) containing mixed polyisobutylene (PIB)/poly(tetramethylene oxide) (PTMO) soft segment was studied under accelerated conditions in 20% H(2)O(2) solution containing 0.1M CoCl(2) at 50 °C to predict resistance to metal ion oxidative degradation (MIO) in vivo. The PIB-based TPUs showed significant oxidative stability as compared to the commercial controls Pellethane 2363-55D and 2363-80A. After 12 weeks in vitro the PIB-PTMO TPUs with 10-20% PTMO in the soft segment showed 6-10% weight loss whereas the Pellethane TPUs degraded completely in about 9 weeks. Attenuated total reflectance Fourier transform infrared spectroscopy confirmed the degradation of Pellethane samples via MIO by the loss of the ∼1110 cm(-1) aliphatic C-O-C stretching peak height attributed to chain scission, and the appearance of a new peak at ∼1174 cm(-1) attributed to crosslinking. No such changes were apparent in the spectra of the PIB-based TPUs. The PIB-based TPUs exhibited 10-30% drop in tensile strength compared to 100% for the Pellethane TPUs after 12 weeks. The molecular weight of the PIB-based TPUs decreased slightly (10-15%) at 12 weeks. The Pellethane TPUs showed a dramatic decrease in M(n) and an increase in low molecular weight degradation product. Scanning electron microscopy (SEM) showed severe cracking in the Pellethane samples after 2 weeks, whereas the PIB-based TPUs exhibited a continuous surface morphology. The weight loss, tensile, and SEM data correlate well with each other and indicate excellent biostability of these materials.

• Authors: David Cozzens, Umaprasana Ojha, Pallavi Kulkarni, Rudolf Faust, Shrojal Desai
• Journal: Journal of biomedical materials research. Part A (J Biomed Mater Res A) Vol. 95 Issue 3 Pg. 774-82 (Dec 01 2010) ISSN: 1552-4965 [Electronic] United States
• PMID: 20725977 (Publication Type: Evaluation Study, Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.

Chemical References

• Biocompatible Materials
• Polyenes
• Polymers
• Polyurethanes
• pellethane 2363-55D
• Cobalt
• polyisobutylene
• cobaltous chloride

Topics

• Biocompatible Materials (chemistry, metabolism)
• Cobalt (chemistry, metabolism)
• Materials Testing
• Microscopy, Electron, Scanning
• Oxidation-Reduction
• Polyenes (chemistry, metabolism)
• Polymers (chemistry, metabolism)
• Polyurethanes (chemistry, metabolism)
• Spectroscopy, Fourier Transform Infrared
• Tensile Strength