TY - JOUR

T1 - Mechanical properties of epoxy/boehmite nanocomposites in dependency of mass fraction and surface modification - An experimental and numerical approach

AU - Jux, M.

AU - Fankhänel, J.

AU - Daum, B.

AU - Mahrholz, T.

AU - Sinapius, M.

AU - Rolfes, R.

N1 - Funding information: This work originates from the Research Unit FOR 2021: “Acting Principles of Nano-Scaled Matrix Additives for Composite Structures”, funded by the German Research Foundation (DFG) (FOR2021). Furthermore, the authors acknowledge the support by the LUIS scientific computing cluster, which is funded by the Leibniz Universität Hannover, the Lower Saxony Ministry of Science and Culture (MWK) and the DFG. The authors wish to express their gratitude for the financial support. The authors also gratefully acknowledge the support from the company Sasol Germany GmbH for providing the modified and non-modified boehmite nanoparticles, for the technical support from the Institute of Materials (IFW) of the Technical University Braunschweig concerning the investigation of fracture surfaces via SEM and the Institute of Composite Structures and Adaptive Systems of the German Aerospace Center (DLR) Braunschweig concerning the preparation of the specimens and the implementation of the experimental tests. This work originates from the Research Unit FOR 2021: “Acting Principles of Nano-Scaled Matrix Additives for Composite Structures”, funded by the German Research Foundation (DFG) ( FOR2021 ). Furthermore, the authors acknowledge the support by the LUIS scientific computing cluster, which is funded by the Leibniz Universität Hannover , the Lower Saxony Ministry of Science and Culture (MWK) and the DFG . The authors wish to express their gratitude for the financial support. The authors also gratefully acknowledge the support from the company Sasol Germany GmbH for providing the modified and non-modified boehmite nanoparticles, for the technical support from the Institute of Materials (IFW) of the Technical University Braunschweig concerning the investigation of fracture surfaces via SEM and the Institute of Composite Structures and Adaptive Systems of the German Aerospace Center (DLR) Braunschweig concerning the preparation of the specimens and the implementation of the experimental tests.

PY - 2018/4/11

Y1 - 2018/4/11

N2 - Boehmite nanoparticles show great potential in improving the matrix dominated mechanical properties of fiber reinforced polymers. For the material design process and the prediction of the nanocomposite's properties, knowledge about the material behavior of the constituent phases and their interactions is crucial. Since the chemical composition of the particle surface can strongly affect the interaction between particle and matrix, the influence of particle surface modification and mass fraction on mechanical properties (tensile modulus, tensile strength, fracture toughness) and failure mechanisms of nanoparticle reinforced epoxy resins is investigated using experimental and numerical methods. In the present work, unmodified and thus chemically reactive boehmite particles are compared to acetic acid modified particles with supposedly lower chemical reactivity and thus worse particle-matrix bonding. A linear relationship between particle mass fraction and tensile modulus/fracture toughness is experimentally found with a maximum increase of 26% in tensile modulus and 62% in critical energy release rate for a particle content of 15 wt%. Furthermore, the experiments indicate that the acetic acid surface modification increases the tensile modulus (up to 6% compared to the unmodified boehmite particles), but at the same time not significantly affects the tensile strength or the fracture toughness. Molecular Dynamic Finite Element Method (MDFEM) simulations are conducted to identify and understand the mechanisms induced by nanoparticles. The material properties of both, modified and unmodified, nanoparticle systems are discussed in relation to the change of particle-matrix bonding strength and interphase morphology. While simulation results of the unmodified system show an outstanding agreement with the experiments, the acetic acid modified system deviates significantly. In conclusion, it seems that additional effects have to be considered to completely understand the material behavior.

AB - Boehmite nanoparticles show great potential in improving the matrix dominated mechanical properties of fiber reinforced polymers. For the material design process and the prediction of the nanocomposite's properties, knowledge about the material behavior of the constituent phases and their interactions is crucial. Since the chemical composition of the particle surface can strongly affect the interaction between particle and matrix, the influence of particle surface modification and mass fraction on mechanical properties (tensile modulus, tensile strength, fracture toughness) and failure mechanisms of nanoparticle reinforced epoxy resins is investigated using experimental and numerical methods. In the present work, unmodified and thus chemically reactive boehmite particles are compared to acetic acid modified particles with supposedly lower chemical reactivity and thus worse particle-matrix bonding. A linear relationship between particle mass fraction and tensile modulus/fracture toughness is experimentally found with a maximum increase of 26% in tensile modulus and 62% in critical energy release rate for a particle content of 15 wt%. Furthermore, the experiments indicate that the acetic acid surface modification increases the tensile modulus (up to 6% compared to the unmodified boehmite particles), but at the same time not significantly affects the tensile strength or the fracture toughness. Molecular Dynamic Finite Element Method (MDFEM) simulations are conducted to identify and understand the mechanisms induced by nanoparticles. The material properties of both, modified and unmodified, nanoparticle systems are discussed in relation to the change of particle-matrix bonding strength and interphase morphology. While simulation results of the unmodified system show an outstanding agreement with the experiments, the acetic acid modified system deviates significantly. In conclusion, it seems that additional effects have to be considered to completely understand the material behavior.

KW - Boehmite

KW - Epoxy resin

KW - Mechanical properties

KW - Nanoparticles

KW - Numerical methods

KW - Surface modification

UR - http://www.scopus.com/inward/record.url?scp=85042910393&partnerID=8YFLogxK

U2 - 10.1016/j.polymer.2018.02.059

DO - 10.1016/j.polymer.2018.02.059

M3 - Article

AN - SCOPUS:85042910393

VL - 141

SP - 34

EP - 45

JO - POLYMER

JF - POLYMER

SN - 0032-3861

ER -