Exceptionally strong, stiff and hard hybrid material based on an elastomer and isotropically shaped ceramic nanoparticles

Prokopios Georgopanos,Ezgi D Yilmaz,Axel Dreyer,Martin Ritter,Artur Feld,Volker Abetz,Ulrich A Handge,Tobias Krekeler,Volkan Filiz,Gerold A Schneider,Horst Weller

doi:10.1038/s41598-017-07521-0

Abstract

In this work the fabrication of hard, stiff and strong nanocomposites based on polybutadiene and iron oxide nanoparticles is presented. The nanocomposites are fabricated via a general concept for mechanically superior nanocomposites not based on the brick and mortar structure, thus on globular nanoparticles with nanosized organic shells. For the fabrication of the composites oleic acid functionalized iron oxide nanoparticles are decorated via ligand exchange with an α,ω-polybutadiene dicarboxylic acid. The functionalized particles were processed at 145 °C. Since polybutadiene contains double bonds the nanocomposites obtained a crosslinked structure which was enhanced by the presence of oxygen or sulfur. It was found that the crosslinking and filler percolation yields high elastic moduli of approximately 12–20 GPa and hardness of 15–18 GPa, although the polymer volume fraction is up to 40%. We attribute our results to a catalytically enhanced crosslinking reaction of the polymer chains induced by oxygen or sulfur and to the microstructure of the nanocomposite.

Highlights

Inspired by biomaterials like nacre the combination of high aspect ratio ceramic nanoparticles and a soft organic matrix is commonly accepted as the pathway to stiff, strong and damage tolerant nanocomposites[1]
The objective of this work is to show that this concept can be applied to other iron oxide nanocomposites, where the oleic acid is replaced by α,ω-polybutadiene dicarboxylic acid, and the overall processing temperature is reduced to 145 °C
PB was chemically characterized by nuclear magnetic resonance spectroscopy (1H-NMR), Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC)

Summary

Introduction

Inspired by biomaterials like nacre the combination of high aspect ratio ceramic nanoparticles and a soft organic matrix is commonly accepted as the pathway to stiff, strong and damage tolerant nanocomposites[1]. Using for iasncnsadtlaewndcitdeotchlloawoyf-snthhaeneaocrpesartraretmiscsilecessnτwPani∝tohpaσarnnr,tawiscphleeicschtisrcaattynipobirce ≈acla l5yr0rs–ime1d0a0bll0ye2rtththeheamtneen1csh0il0aen nsitmcraelstlhsyeewsseeσanpkianortrtihgcaelnensiacanmroepaftalraritwxi.cAtleossletarhraeendlteonawngntdh-, very strong due to their covalent/ionic bonds[1] This mechanical concept provides likewise hard, stiff and strong as well as damage tolerant nanocomposites, which overcome the weakness of one material class and achieve multi-functionality[2,3,4,5,6,7]. Moderate heat treatment up to 350 °C triggered the cross-linking of the oleic acid molecules, which were attached to the iron oxide by their carboxyl groups and resulted in nanocomposites with a nanohardness of 4 GPa, an elastic modulus of 80 GPa and a strength of 500 MPa in micromechanical bending tests[8] This result demonstrates that the above mentioned concept based on high aspect ratio nanoparticles is not necessary to achieve hard, stiff and strong nanocomposites[8]. The objective of this work is to show that this concept can be applied to other iron oxide nanocomposites, where the oleic acid is replaced by α,ω-polybutadiene dicarboxylic acid, and the overall processing temperature is reduced to 145 °C

Objectives

Methods

Results

Conclusion