TY - JOUR

T1 - Influence of layer architecture on fracture toughness and specimen stiffness in polymer multilayer composites

AU - Wiener, Johannes

AU - Arbeiter, Florian

AU - Kolednik, Otmar

AU - Pinter, Gerald

N1 - 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)

PY - 2022/7

Y1 - 2022/7

N2 - 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.

AB - 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.

KW - Biomimetic design

KW - Fracture mechanics

KW - Material inhomogeneity effect

KW - Multilayer

KW - Polypropylene

UR - http://www.scopus.com/inward/record.url?scp=85132372604&partnerID=8YFLogxK

U2 - 10.1016/j.matdes.2022.110828

DO - 10.1016/j.matdes.2022.110828

M3 - Article

AN - SCOPUS:85132372604

VL - 219.2022

JO - Materials and Design

JF - Materials and Design

SN - 0264-1275

IS - July

M1 - 110828

ER -