TY - JOUR

T1 - Bioinspired fracture toughness enhancement of a fully bio-based epoxy resin

AU - Schwaiger, Markus

AU - Waly, Christoph

AU - Huszar, Michael

AU - Oreski, Gernot

AU - Feuchter, Michael

AU - Arbeiter, Florian

AU - Resch-Fauster, Katharina

N1 - Funding Information: Part of this research work was funded by the Federal Ministry for Climate Action, Environment, Energy, Mobility, Innovation and Technology in frame of the program “Produktion der Zukunft” under contract no. 871403 , within the context of the project “Semiflexible and flexible composites based on renewable resources”, as well as by the Federal Ministry for Transport, Innovation and Technology and the Federal Ministry for Digital and Economic Affairs in frame of the COMET-program under contract no. 854178 , within the COMET-project 3.S4 at the Polymer Competence Center Leoben GmbH (PCCL, Austria). The PCCL is funded by the Austrian Government and the State Governments of Styria, Lower Austria and Upper Austria . The funding of Montanuniversitaet Leoben for Open Access publishing is gratefully acknowledged. Publisher Copyright: © 2023 The Authors

PY - 2023/7

Y1 - 2023/7

N2 - In this work, the concept of fracture toughness improvement via spatial variation of mechanical properties is applied to a composite with 100% bio-based carbon content based on epoxidized linseed oil. By proper selection of the hardener, either citric acid or sebacic acid, the mechanical properties were adjusted in a way that a bio-composite exhibits a stiff-soft-stiff layer architecture. Samples with two different thicknesses of soft interlayer (approx. 0.1 mm and 1.3 mm) were subsequently analyzed regarding their final performance. Specimen characteristics, owing to the curing and manufacturing process, were analyzed by means of local Fourier-transform infrared spectroscopy and differential scanning calorimetry. Fracture mechanics tests were performed to verify if the soft interlayer acts as a crack arrester. The results propose a high chemical compatibility between the used epoxy resins. Embedding a soft thin interlayer into a stiff resin matrix led to an increase in fracture toughness of 13 times, compared to the pure stiff resin. An increase in interlayer thickness led to a further increase in fracture toughness of 24 times. However, the stiffness decreased by 44% and 67%, respectively.

AB - In this work, the concept of fracture toughness improvement via spatial variation of mechanical properties is applied to a composite with 100% bio-based carbon content based on epoxidized linseed oil. By proper selection of the hardener, either citric acid or sebacic acid, the mechanical properties were adjusted in a way that a bio-composite exhibits a stiff-soft-stiff layer architecture. Samples with two different thicknesses of soft interlayer (approx. 0.1 mm and 1.3 mm) were subsequently analyzed regarding their final performance. Specimen characteristics, owing to the curing and manufacturing process, were analyzed by means of local Fourier-transform infrared spectroscopy and differential scanning calorimetry. Fracture mechanics tests were performed to verify if the soft interlayer acts as a crack arrester. The results propose a high chemical compatibility between the used epoxy resins. Embedding a soft thin interlayer into a stiff resin matrix led to an increase in fracture toughness of 13 times, compared to the pure stiff resin. An increase in interlayer thickness led to a further increase in fracture toughness of 24 times. However, the stiffness decreased by 44% and 67%, respectively.

KW - Bio-based epoxy resin

KW - Bio-composite

KW - Epoxidized linseed oil

KW - Fracture toughness

KW - Layered structures

KW - Material inhomogeneity

UR - http://www.scopus.com/inward/record.url?scp=85161262816&partnerID=8YFLogxK

U2 - 10.1016/j.polymertesting.2023.108098

DO - 10.1016/j.polymertesting.2023.108098

M3 - Article

AN - SCOPUS:85161262816

VL - 124.2023

JO - Polymer Testing

JF - Polymer Testing

SN - 0142-9418

IS - July

M1 - 108098

ER -