Samuel Thomas Buschhorn

Hamburger Institut für Wertschöpfungssystematik und Wissensmanagement

Ice protection systems (IPS) are critical components for many aerospace flight vehicles, including commercial transports and unmanned aerial systems (UAS), and can include anti-icing, de-icing, ice sensing, etc. Here, an IPS is created using nanomaterials to create a surface-modified external layer on an aerosurface based on observations that polym...

We report on the rheological properties of semidilute carbon nanotube (CNT)/epoxy suspensions with varying filler content prepared with different dispersion methods. We show that dispersion techniques can be distinguished by means of the rheological response. It was found that the suspensions undergo a lasting dispersion changes during the first sh...

A practical overview of possibilities and limits to characterize the state of dispersion of carbon nanotubes (CNT) in polymer based nanocomposites is given. The most important and widely available methods are discussed with practical employment in mind. One focus is the quantitative characterization of the state of dispersion in solid samples using...

This paper considers a novel electro-thermal system combining aligned carbon nanotubes (A-CNT) as a resistive heater and bistable laminates. The use of A-CNT heaters to actuate bistable laminates is characterized in terms of steady-state shape as a function of applied voltage to the heating element and the transient response of the laminate to heat...

Here, we quantify the electron transport properties of aligned carbon nanotube (CNT) networks as a function of the CNT length, where the electrical conductivities may be tuned by up to 10× with anisotropies exceeding 40%. Testing at elevated temperatures demonstrates that the aligned CNT networks have a negative temperature coefficient of resistanc...

In this paper we present characterization data for carbon nanotube (CNT)-epoxy and thermally reduced graphene oxide (TRGO)-epoxy nano-composites. The frequency-dependent ac conductivity and permittivity are examined as a function of volume fraction of carbon-based filler. The measured electrical properties and their frequency dependency are evaluat...

Moisture and water uptake of epoxy/multi-wall carbon nanotube (MWCNT) composites was studied in a wide range of atmosphere relative humidity and temperatures. Addition of up to 1 wt.% of MWCNTs into the neat epoxy resulted to the twofold decrease of the diffusivity, while the levels of moisture/water uptake remained unchanged. The positive effect o...

The interconnection of solar cells is one of the main process steps in photovoltaic module production. Usually solar cells are connected into strings by soldering. Due to cell thickness reduction and substantial changes of solar cell metallization, alternative interconnection techniques are required. The thermomechanically induced stress, caused by...

A range of properties of two commercial thermoplastic ethylene-vinyl acetate (EVA) copolymers, Elvax 420 and Elvax 450, neat and as melt-mixed composite filled with 15 wt.-% of multiwall carbon nanotubes (MWCNTs), are studied in the ‘‘as produced’’ state and after hydrothermal ageing. Addition of MWCNTs into the neat copolymers introduces the funct...

The electrical percolation behavior of multiwall carbon nanotubes epoxy composites produced using sonication as dispersion process is studied. The electrical properties of the cured composites are related to the different internal carbon nanotube networks induced by the processing parameters. A fine tuning of the electrical conductivity is obtained...

Creep and creep–recovery of epoxy/multi-wall carbon nanotube (MWCNT) composites was studied in a wide range of applied loads in order to evaluate the contribution of nanotubes on the time-dependent behaviour of the epoxy matrix. Incorporation of up to 1 wt.% of C150P MWCNTs has negligible influence on the elastic, viscoelastic and viscoplastic resp...

This report investigates the steady-state viscosities of multiwall carbon nanotube (MWCNT)/epoxy and carbon nanofiber (CNF)/epoxy suspensions with varying filler concentrations under different shear rates at various temperatures. In situ observation of filler networks suggests the build-up of shear induced MWCNT and CNF agglomerates at low shear ra...

The interconnection of solar cells is one of the main process steps in photovoltaic module production. Usually solar cells are connected into strings by soldering. The thermo mechanically induced stress, which is caused by high soldering temperature and different coefficients of thermal expansion, limits modules long-term reliability. The use of co...

In the present work we use a perylene derivative (PTCDA) as compatibilizer between epoxy resin and multi-walled carbon nanotubes (MWCNT). The electrical conductivity of epoxy/PTCDA/MWCNT suspensions (i.e. without any hardener) decreased, due to an improved MWCNT dispersion. On the other hand, a high electrical conductivity could be attained after c...

In this work the rheological and electrical properties of semi-dilute carbon nanotube (CNT)–epoxy suspensions have been discussed. The suspensions are produced using two types of industrially available CNTs (Nanocyl 3150 and 7000) and using two different dispersion techniques, namely 3-roll milling and sonication. In-situ optical microscopic analys...

Visualization of embedded carbon nanotubes (CNTs) in polymer using a scanning electron microscope (SEM) has been established as a convenient technique to evaluate CNT dispersion. This technique is known as voltage contrast imaging and is different from material contrast and topographic contrast imaging. By investigating CNT/epoxy composites the vol...

Epoxy nanocomposite suspensions including multi-wall carbon nanotubes (MWCNTs) and carbon black (CB) were produced and investigated by means of combined rheological and electrical analysis. The rheological percolation behaviour was compared to the electrical percolation behaviour. Due to similar dynamic agglomeration mechanisms the difference betwe...

Es wird ein praxisnaher Überblick über die Möglichkeiten und Grenzen der Charakterisierung der Dispersionsgüte von Carbon Nanotubes (CNTs, deutsch: Kohlenstoffnanoröhren) in polymerbasierten Nanokompositen gegeben. Die wichtigs-ten und am besten verfügbaren Methoden werden anwendungsorientiert vorgestellt. Einen Schwerpunkt bildet die quantitative...

The dielectric properties of epoxy/short carbon fiber composites at different concentrations 0, 5, 10 and 15% by weight, different thicknesses 2 and 4mm, and frequency in the range from 20Hz to 1MHz were characterized. Scanning electron microscopy and differential scanning calorimetry were utilized. The alternating current (ac) electrical propertie...

In this paper, electrically conductive epoxy based nanocomposites based on multiwall carbon nanotubes and carbon black were investigated concerning their potential for strain sensing applications with electrical conductivity methods. This paper aims to investigate the electromechanical response of the nanocomposite matrices subjected to mechanical...

Epoxy nanocomposites including carbon nanotubes (MWCNT) and carbon black (CB) were investigated by means of their electrical and rheological percolation behaviour. Due to synergistic dynamic effects in charge transport the inclusion of both MWCNT and CB in a multiphase epoxy system leads to the same electrical behaviour compared to the binary MWCNT...

Electrically conductive polymer nanocomposites have potential for health monitoring and strain-sensing in structural polymer components. In this work CNT/epoxy-based material for direction sensitive strain sensing beams is produced in a simple process. The material is characterised and beams are tested in a 3-point bending setup where they exhibit...

In the present work, a direction sensitive bending strain sensor consisting of a single block of epoxy/multi-wall carbon nanotube composite was developed. Moreover, the manufacturing could be realized in a straightforward single-step processing route. The directional sensitivity to bending deformations is related to the change in electrical resista...