title: Porous poly(para-phenylene) scaffolds for load-bearing orthopedic applications.
abstract: The focus of this study was to fabricate and investigate the mechanical behavior of porous poly(para-phenylene) (PPP) for potential use as a load-bearing orthopedic biomaterial. PPPs are known to have exceptional mechanical properties due to their aromatic backbone; however, the manufacturing and properties of PPP porous structures have not been previously investigated. Tailored porous structures with either small (150-250µm) or large (420-500µm) pore sizes were manufactured using a powder-sintering/salt-leaching technique. Porosities were systematically varied using 50 to 90vol%. Micro-computed tomography (µCT) and scanning electron microscopy (SEM) were used to verify an open-cell structure and investigate pore morphology of the scaffolds. Uniaxial mechanical behavior of solid and porous PPP samples was characterized through tensile and compressive testing. Both modulus and strength decreased with increasing porosity and matched well with foam theory. Porous scaffolds showed a significant decrease in strain-to-failure (<4%) under tensile loading and experienced linear elasticity, plastic deformation, and densification under compressive loading. Over the size ranges tested, pore size did not significantly influence the mechanical behavior of the scaffolds on a consistent basis. These results are discussed in regards to use of porous PPP for orthopedic applications and a prototype porous interbody fusion cage is presented.
authors.affiliation: University of Wyoming, Department of Mechanical Engineering, Laramie, WY 82071, USA.
authors.forename: Amy L
authors.initials: AL
authors.lastname: DiRienzo
authors.affiliation: University of Colorado Denver, Department of Mechanical Engineering, Denver, CO, USA.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Yakacki
authors.affiliation: INM-Leibniz Institute for New Materials, Functional Surfaces Group, Saarbrücken, Germany.
authors.forename: Mareike
authors.initials: M
authors.lastname: Frensemeier
authors.affiliation: Development and Plate-Design, AG der Dillinger Hüttenwerke, Dillingen, Germany.
authors.forename: Andreas S
authors.initials: AS
authors.lastname: Schneider
authors.affiliation: MedShape Inc., Department of Research & Development, Atlanta, GA, USA.
authors.forename: David L
authors.initials: DL
authors.lastname: Safranski
authors.affiliation: University of Wyoming, Department of Mechanical Engineering, Laramie, WY 82071, USA.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Hoyt
authors.affiliation: University of Wyoming, Department of Mechanical Engineering, Laramie, WY 82071, USA. Electronic address: cfrick@uwyo.edu.
authors.forename: Carl P
authors.initials: CP
authors.lastname: Frick
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D002712:Chlorides / Q000737:chemistry; D019245:Compressive Strength; D003516:Cycloparaffins / Q000737:chemistry*; D055595:Mechanical Phenomena; D009985:Orthopedics / Q000379:methods*; D016062:Porosity; D013314:Stress, Mechanical; D013718:Tensile Strength; D055114:X-Ray Microtomography
chemical_list: D001672:Biocompatible Materials; D002712:Chlorides; D003516:Cycloparaffins; C509547:poly-para-phenylene
keywords: Biomedical devices; Mechanical behavior; Poly(para-phenylenes); Porous biomaterials; Scanning electron microscopy