Failure mechanisms, electrical and thermal conductivity of Aerographite/epoxy composite

Volume
2015-July
Citation
ICCM International Conferences on Composite Materials (2015-July): (2015)
Contribution to Conference
20th International Conference on Composite Materials, ICCM 2015  
Aerographite (AG) is a novel hierarchical carbon nanomaterial formed by a 3D-network of directly interconnected thin-walled graphite layers with densities in rage of 0.2-15 mg/cm3 [1]. AG is synthesized using a single-step CVD process on ZnO templates where simultaneous deposition of graphitic layers and etching of Zn takes place. Despite the ultra-low density, Aerographite's unique morphology consisting of tubular, interconnected graphitic hollow tetrapods enables infiltration with a polymeric matrix. Aerographite/epoxy nanocomposites have been prepared using a novel, proprietary vacuum assisted infiltration technique. The density and the electrical conductivity of the neat AG used for the preparation of the composite is ~12 mg/cm3 and 2-3 S/m respectively. Optical investigations confirm that the 3D interconnected structure remains in-tact during the infiltration process. The composite after infiltration with epoxy was characterized for its electrical and mechanical properties. The electrical conductivity of AG/composite was 7-8 S/m for 0.85-0.88 wt% of AG content. Preliminary results on fracture toughness (KIC) showed an enhancement of 19 % in KIC for AG/epoxy composite with 0.45 wt% of AG. Observations of fractured surfaces under scanning electron microscope gives evidence of pull-out of arms of AG tetrapod, interface and inter-graphite failure as the dominating mechanism for the toughness improvement in these composites. Evidence of increased energy absorption were observed through compression tests and via interaction of crack front with an AG network through photoelasticity experiments.
Subjects
3D graphene network
Electrical conductivity
Failure mechanisms
DDC Class
600: Technik
More Funding Information
We would like to acknowledge European Union Seventh Framework Programme under grant agreement no604391 Graphene Flagship for the financial support. The co-author Mr. Matthias Mecklenburg would like to acknowledge German Research Foundation (DFG) via SFB 986 M³, project B1 for funding his work at TUHH.