Influence of layer architecture on fracture toughness and specimen stiffness in polymer multilayer composites

Johannes Wiener, Florian Arbeiter, Otmar Kolednik, Gerald Pinter

Research output: Contribution to journalArticleResearchpeer-review


The objective of this contribution was to increase the fracture toughness of talcum reinforced polypropylene (PP) while preserving specimen stiffness. This was accomplished by introducing soft interlayers (ILs) made of standard PP (PP-St) or very compliant PP (PP-Soft) and utilizing the so-called material inhomogeneity effect. Architectures with one or two ILs of either 0.3 or 0.9 mm thickness were tested in single edge notched bending experiments. Layers of PP-Soft always arrested growing cracks due to their low Young’s modulus, E, and yield stress, , which is called an (-inhomogeneity. However, the increase in fracture toughness came at the cost of specimen stiffness. For ILs made of PP-St, E was still lower compared to the matrix material, but was similar (pure E-inhomogeneity). Specimen stiffness remained high for these composites, but crack arrest could not be achieved in most cases, which could be explained by plastic deformation of the soft layers. Plastic deformation could be contained within the ILs in one of the architectures, where two large ILs were used. Crack arrest could be achieved in this adapted IL design, leading to excellent fracture toughness in combination with high stiffness.
Original languageEnglish
Article number110828
Number of pages10
JournalMaterials and Design
Issue numberJuly
Early online date8 Jun 2022
Publication statusPublished - Jul 2022

Bibliographical note

Funding Information:
This research was supported by the Austrian Research Promotion Agency (FFG) as part of the project “Entwicklung und Optimierung von hoch risszähen, polymeren Mehrschicht-Verbundsystemen nach biomimetischen Prinzipien”, grant agreement 858562, referred to with the acronym “BioMimicPolymers”. Special thanks go to Nina Hochrainer and Franz Grassegger for the diligent preparation of the test specimens.

Publisher Copyright:
© 2022 The Author(s)


  • Biomimetic design
  • Fracture mechanics
  • Material inhomogeneity effect
  • Multilayer
  • Polypropylene

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