Structure-property relationships in biomedical thermoplastic polyurethane nanocomposites

Osman, Azlin F., Edwards, Grant A., Schiller, Tara L., Andriani, Yosephine, Jack, Kevin S., Morrow, Isabel C., Halley, Peter J. and Martin, Darren J. (2012) Structure-property relationships in biomedical thermoplastic polyurethane nanocomposites. Macromolecules, 45 1: 198-210. doi:10.1021/ma202189e

Author Osman, Azlin F.
Edwards, Grant A.
Schiller, Tara L.
Andriani, Yosephine
Jack, Kevin S.
Morrow, Isabel C.
Halley, Peter J.
Martin, Darren J.
Title Structure-property relationships in biomedical thermoplastic polyurethane nanocomposites
Journal name Macromolecules   Check publisher's open access policy
ISSN 0024-9297
Publication date 2012-01-10
Year available 2011
Sub-type Article (original research)
DOI 10.1021/ma202189e
Volume 45
Issue 1
Start page 198
End page 210
Total pages 13
Place of publication Washington, DC, United States
Publisher American Chemical Society
Collection year 2012
Language eng
Formatted abstract
Polyurethanes are excellent potential materials for the construction of implantable medical components due to their exceptional mechanical properties and biocompatibility. Currently, soft silicone materials are employed as insulation for implantable cochlear electrode arrays. Siloxane-based thermoplastic polyurethane (TPU) nanocomposites containing synthetic layered silicates are being investigated as new insulation materials with superior tensile and tear strength and reduced surface tack, potentially allowing for thinner insulation and more intricate electrode designs. In this work, ElastEon E5-325 (Aortech Pty Ltd.) TPU nanocomposites reinforced with 2 and 4 wt % low aspect ratio organo-hectorite and high aspect ratio organo-fluoromica (Lucentite SWN, Somasif ME100, both modified with octadecyltrimethylammonium (ODTMA)) were prepared by a solvent casting technique. The mechanical properties of the resulting nanocomposites were measured by tensile, tear, stress relaxation, and creep testing and morphologically were characterized by DSC, DMTA, XRD, TEM, and strained in situ synchrotron SAXS. We found that the hydrophobic low aspect ratio organohectorite acts as a very potent interfacial compatibilizer. At 2 wt % loading, the resulting nanocomposite displays vastly superior mechanical properties to both soft silicone and ElastEon. In addition to providing 30 nm × 1 nm synthetic nanosilicate reinforcing elements which are readily capable of orientation and reinforcement, these nanosilicates also serve to provide more cohesive hard microdomains and thus creep resistance and dimensional stability. Interestingly, at a higher (4 wt %) loading of organohectorite, gross morphological changes in the TPU microdomain texture are observed, adversely effecting the mechanical properties of the TPU.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Publication Date (Web): December 12, 2011

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