PhD Thesis Defense: Peder Solberg

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Meeting ID: 931 0462 8220
Passcode: 173786

"Application-Driven Materials Development of Solid-State Conductive Composites of Ultra-High Molecular Weight Polyethylene"

Abstract

Ultra-high molecular weight polyethylene (UHMWPE) is a polymer valued for its toughness, wear resistance, and chemical inertness. In the medical field, these properties make it the material of choice for bearing surfaces despite recognized tradeoffs between wear resistance, toughness, and oxidation resistance. Electrically conductive composites of UHMWPE show promise to enable new types of smart and active load-bearing implants in a future of personalized medicine, if beneficial properties can be maintained with the addition of solid-state additives.

Clinical need-finding conducted through Dartmouth’s Training Program in Surgical Innovation revealed several potential applications for conductive, load-bearing polymers. These include:

1. conductive knee bearings for treatment of prosthetic joint infection
2. strain sensors for spinal and arthroplasty applications, and
3. electrodes for embedded sensors in orthopedic bearings.

Each application area demands specific material properties, requiring a framework for producing a tough, conductive polymer composite with adjustable parameters while considering property tradeoffs.

Carbon black nanoparticles were added to UHMWPE to confer conductive properties while providing good interphase adhesion. A range of carbon black concentrations were tested to understand the effect of additive concentration on certain mechanical and electrical properties relevant to highly-loaded applications. Results provided a key understanding of the deformation behavior of conductive nanoparticles in these materials. Furthermore, results showed that these composites can simultaneously meet mechanical and electrical requirements for the applications of interest. Overall, this work demonstrated mechanical and electrical viability of these materials for clinical applications while providing a deeper understanding of structure-property relationships in solid-state, electrically conductive composites of UHMWPE.

Thesis Committee

• Douglas Van Citters
• Ian Baker
• John XJ Zhang
• Igor Tsukrov (external)

Contact

For more information, contact Thayer Registrar at thayer.registrar@dartmouth.edu.