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Water as blowing agent in polyurethane resins creating porous cancellous bone surrogates for biomechanical osteosynthesis applications

  • Marianne Hollensteiner

    Marianne Hollensteiner, born in 1983, is a Privatdozent (PD) in Experimental Orthopedics and Traumatology and holds a PhD in medical sciences. She has a Dipl.-Ing. and a Bachelor of Science in Medical Engineering as well as a Master of Science in Health Sciences and Leadership. She is the Deputy Head of the Institute of Biomechanics at BG Trauma Clinic Murnau and leads the Department of Mechanical Testing. In this role, her research focuses particularly on the development and application of synthetic bone models for biomechanical evaluation of osteosynthesis techniques and orthopedic implants.

     ORCID logo EMAIL logo     , Sascha Senck

    Sascha Senck, PhD was born on 16.03.1980. He completed his PhD studies in biology, with a focus on computed tomography and bone morphometric analyses at the University of Vienna in 2012. Currently, he holds a position as Senior Researcher and Assistant Professor at the University of Applied Sciences Upper Austria, Campus Wels, where he leads multiple research projects in the Research Group Computed Tomography. His expertise focuses on the three-dimensional characterization of additively manufactured materials and biological hard tissues using advanced X-ray and phase contrast imaging techniques.

         , Sarah Heupl

    Sarah Heupl was born on December 4, 1993. She completed her studies in technical chemistry at the Technical University of Graz in 2019. Currently, she works as a research project manager in the computed tomography research group at the University of Applied Sciences Upper Austria in Wels, Austria. Her focus is on combining computed tomography with testing, e.g. ex-situ loading tests, in-situ tensile tests, and degradation monitoring. The combination with the chemical background leads to an improved understanding of damage mechanisms and structure-property relationships.

         and Peter Augat

    Peter Augat, born in 1963, is a Professor of Biomechanics at Paracelsus Medical University in Salzburg, Austria, and serves as the Director of the Institute of Biomechanics at the Trauma Center Murnau, Germany. He received his Master of Science in Physics from the University of Ulm in 1990 and completed his PhD in Biology in 1995. His research focuses on the biomechanics of musculoskeletal injuries and the development of advanced methods for the evaluation and improvement of orthopedic treatments and implants.
Published/Copyright: March 27, 2025
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Materials Testing
From the journal Materials Testing Volume 67 Issue 5

Abstract

This study examines the role of water as a blowing agent in generating porous polyurethane foams used as synthetic cancellous bone surrogates in biomechanical osteosynthesis testing. Polyurethane foams, typically used to replicate bone structures, often fail to fully mimic the intricate morphology and mechanical properties of natural bone, especially in open-cell, cancellous structures. By varying water content, with and without a cell-stabilizing agent, foams with distinct morphological and mechanical characteristics were produced. Morphometric analysis and mechanical compression testing were conducted on foams with water content ranging from 0.25 to 3 wt.%. Results indicate that decreasing water content yields denser, mechanically stiffer foams, whereas the stabilizer consistently enhanced cellular stability and uniformity. Quantitative analysis, including bone volume to total volume ratio, trabecular thickness, and connectivity density, demonstrated that specific water-stabilizer combinations align more closely with human trabecular bone. These findings suggest that optimized water-based foaming in polyurethane can improve synthetic bone models’ biomechanical fidelity, offering valuable implications for testing orthopedic implants.

Keywords: compression testing; bone biomechanics; bone surrogate; open celled trabecular bone; bone morphometry
Corresponding author: Marianne Hollensteiner, Institute for Biomechanics, BG Unfallklinik Murnau, Murnau, 82418, Germany, E-mail:

About the authors

Marianne Hollensteiner

Marianne Hollensteiner, born in 1983, is a Privatdozent (PD) in Experimental Orthopedics and Traumatology and holds a PhD in medical sciences. She has a Dipl.-Ing. and a Bachelor of Science in Medical Engineering as well as a Master of Science in Health Sciences and Leadership. She is the Deputy Head of the Institute of Biomechanics at BG Trauma Clinic Murnau and leads the Department of Mechanical Testing. In this role, her research focuses particularly on the development and application of synthetic bone models for biomechanical evaluation of osteosynthesis techniques and orthopedic implants.

Sascha Senck

Sascha Senck, PhD was born on 16.03.1980. He completed his PhD studies in biology, with a focus on computed tomography and bone morphometric analyses at the University of Vienna in 2012. Currently, he holds a position as Senior Researcher and Assistant Professor at the University of Applied Sciences Upper Austria, Campus Wels, where he leads multiple research projects in the Research Group Computed Tomography. His expertise focuses on the three-dimensional characterization of additively manufactured materials and biological hard tissues using advanced X-ray and phase contrast imaging techniques.

Sarah Heupl

Sarah Heupl was born on December 4, 1993. She completed her studies in technical chemistry at the Technical University of Graz in 2019. Currently, she works as a research project manager in the computed tomography research group at the University of Applied Sciences Upper Austria in Wels, Austria. Her focus is on combining computed tomography with testing, e.g. ex-situ loading tests, in-situ tensile tests, and degradation monitoring. The combination with the chemical background leads to an improved understanding of damage mechanisms and structure-property relationships.

Peter Augat

Peter Augat, born in 1963, is a Professor of Biomechanics at Paracelsus Medical University in Salzburg, Austria, and serves as the Director of the Institute of Biomechanics at the Trauma Center Murnau, Germany. He received his Master of Science in Physics from the University of Ulm in 1990 and completed his PhD in Biology in 1995. His research focuses on the biomechanics of musculoskeletal injuries and the development of advanced methods for the evaluation and improvement of orthopedic treatments and implants.

  1. Research ethics: Not applicable.

  2. Informed consent: Not applicable.

  3. Author contributions: The authors have accepted responsibility for the entire content of this manuscript and approved its submission.

  4. Use of Large Language Models, AI and Machine Learning Tools: Artificial intelligence tools (DeepL.com and QuillBot.com) were employed to enhance the language quality of the manuscript.

  5. Conflict of interests: The authors state no conflict of interest.

  6. Research funding: None declared.

  7. Data availability: The raw data can be obtained on request from the corresponding author.

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Published Online: 2025-03-27
Published in Print: 2025-05-26

© 2025 Walter de Gruyter GmbH, Berlin/Boston

Articles in the same Issue

  1. Frontmatter
  2. Review on three-point bending test for evaluating the mechanical properties, fracture behavior, and adhesion strength of coating/substrate systems
  3. Gas metal arc weldability of a Strenx 700MC-AISI304 dissimilar joint
  4. Effect of process parameters on mechanical properties of 5554 aluminum alloy fabricated by wire arc additive manufacturing
  5. Coating of TIG-welded micro-alloyed 38MnVS6 steel with flux-cored wire and FeB addition: microstructure, hardness, and wear properties
  6. Manufacturing parameters’ effects on the flexural properties of 3D-printed PLA
  7. Modified hot-spot stress method for fatigue life estimation of welded components
  8. Water as blowing agent in polyurethane resins creating porous cancellous bone surrogates for biomechanical osteosynthesis applications
  9. Enhancing cervical spine health: a vibration-focused multibody dynamics model for neck support system design
  10. Characterization of novel fibers extracted from Rumex obtusifolius L. plant for potential composite applications
  11. Interface metallurgical characteristics of dissimilar friction welded steels
  12. Effect of atmospheric pressure plasma treatment on the wettability and aging behavior of metal surfaces
  13. Microstructure and mechanical properties of dissimilar ferritic (S355)–austenitic (AISI 304) steel joints welded by robotic GMAW
  14. Enhanced Greylag Goose optimizer for solving constrained engineering design problems
  15. Effect of sustainable cooling and lubrication method on the hole quality and machinability performance in drilling of AA7075 alloy with cryogenically treated carbide drills
  16. Design optimization of a connecting rod for energy savings
https://doi.org/10.1515/mt-2024-0486
Keywords for this article
compression testing; bone biomechanics; bone surrogate; open celled trabecular bone; bone morphometry

Articles in the same Issue

  1. Frontmatter
  2. Review on three-point bending test for evaluating the mechanical properties, fracture behavior, and adhesion strength of coating/substrate systems
  3. Gas metal arc weldability of a Strenx 700MC-AISI304 dissimilar joint
  4. Effect of process parameters on mechanical properties of 5554 aluminum alloy fabricated by wire arc additive manufacturing
  5. Coating of TIG-welded micro-alloyed 38MnVS6 steel with flux-cored wire and FeB addition: microstructure, hardness, and wear properties
  6. Manufacturing parameters’ effects on the flexural properties of 3D-printed PLA
  7. Modified hot-spot stress method for fatigue life estimation of welded components
  8. Water as blowing agent in polyurethane resins creating porous cancellous bone surrogates for biomechanical osteosynthesis applications
  9. Enhancing cervical spine health: a vibration-focused multibody dynamics model for neck support system design
  10. Characterization of novel fibers extracted from Rumex obtusifolius L. plant for potential composite applications
  11. Interface metallurgical characteristics of dissimilar friction welded steels
  12. Effect of atmospheric pressure plasma treatment on the wettability and aging behavior of metal surfaces
  13. Microstructure and mechanical properties of dissimilar ferritic (S355)–austenitic (AISI 304) steel joints welded by robotic GMAW
  14. Enhanced Greylag Goose optimizer for solving constrained engineering design problems
  15. Effect of sustainable cooling and lubrication method on the hole quality and machinability performance in drilling of AA7075 alloy with cryogenically treated carbide drills
  16. Design optimization of a connecting rod for energy savings
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