On the toughness of photopolymerizable (meth)acrylate networks for biomedical applications

Authors

  • Kathryn E. Smith,

    Corresponding author
    1. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta 30332, GA
    • Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta 30332, GA
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  • Johnna S. Temenoff,

    1. Wallace H. Coulter Department of Biomedical Engineering, Georgia Tech and Emory University, 313 Ferst Drive, Georgia Institute of Technology, Atlanta 30332, GA
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  • Ken Gall

    1. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta 30332, GA
    2. School of Materials Science and Engineering, Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta 30332, GA
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Abstract

Photopolymerizable networks are being explored for a variety of biomedical applications because they can be formed in situ, rendering them useful in minimally invasive procedures. The purpose of this study was to establish fundamental relationships between toughness, network chemical structure, and testing temperature of photopolymerizable (meth)acrylate networks deformed in air and under hydrated conditions. Networks were formed by combining at least one monofunctional (meth)acrylate with a difunctional methacrylate, and weight ratios were adjusted to vary the degree of crosslinking, elastic modulus, and glass transition temperature (Tg). Stress–strain behavior and toughness were determined by performing tensile strain to failure tests at temperatures spanning the glassy and rubbery regimes of each network both in air and phosphate-buffered saline. In air, all of the networks demonstrated a peak in toughness below the network's Tg. At an “equivalent” test temperature relative to Tg, crosslinking concentration and monomer chemistry influenced the toughness of each network. Apparent toughness is significantly altered in an aqueous environment, an effect driven by water absorption into the network causing the Tg to decrease. The results from this study provide the fundamental knowledge required to guide the development of tougher photopolymerizable networks for mechanically strenuous biomedical applications. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

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