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Dive into the research topics where Michael Heitzmann is active.

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Featured researches published by Michael Heitzmann.


Journal of Chromatography A | 2015

Inverse gas chromatography for natural fibre characterisation: Identification of the critical parameters to determine the Brunauer–Emmett–Teller specific surface area

A. Legras; A. Kondor; Michael Heitzmann; R. W. Truss

Inverse gas chromatography (IGC) is an alternative technique to determine the specific surface area of natural fibres. Natural fibres have a complex surface chemistry and unique microstructure that challenge the current capabilities to perform surface characterisation. This study investigated the influence of multiple parameters on the measured Brunauer-Emmett-Teller (BET) specific surface area for samples of flax, kenaf and BioMid(®) cellulose fibres using IGC. The BET surface area of kenaf and flax differed with 0.51m(2)g(-1) and 1.35m(2)g(-1) respectively, the former being similar to the cellulose fibres (0.54m(2)g(-1)). The data was calculated under conditions where the BET equation showed good linearity (R(2)⩾0.995). Repeatability was excellent so that two runs sufficed to obtain representative BET surface area values. The findings showed the choice of solvent was important for all specimens to avoid any misleading data comparison due to molecular orientation effects that impact the adsorbent-adsorbate interactions. The higher surface area of the flax sample, and its higher variability, was correlated with a higher surface roughness observed under optical microscopy. Packing the chromatography column with long or chopped fibres produced results that were statistically insignificant.


Journal of Polymers and The Environment | 2013

Single-Plant Biocomposite from Ricinus Communis: Preparation, Properties and Environmental Performance

Michael Heitzmann; M. Veidt; Ching-Tai Ng; B. Lindenberger; Meng Hou; R. W. Truss; Chin Kian Liew

A single-plant biobased composite material was prepared from fibre and matrix constituents produced from the castor plant, ricinus communis. It is shown that the mechanical properties of the castor plant fibres are comparable to those of other bast fibres and that the stiffness and strength characteristics of the castor fibre/polyamide 11 biocomposite compare well with those of other natural fibre composites. By using a biobased thermoplastic matrix material the reliance on non-renewable feedstock sources is reduced and end-of-lifetime recyclability is improved. The analysis of the environmental performance of the new castor plant composite suggests that the biobased material has great potential as a sustainable alternative replacing glass fibre-reinforced plastics.


Advanced Materials Research | 2011

Morphology of an Interface between Polyetherimide and Epoxy Prepreg

Michael Heitzmann; Meng Hou; M. Veidt; Luigi-Jules Vandi; Rowan Paton

The morphology of the interface between a commercial epoxy prepreg resin (HexPly M18/1) and Polyetherimide (PEI) is studied. Different cure cycles prescribed by the supplier were investigated to determine the influence of temperature and pressure on interface formation. Atomic Force Microscopy (AFM) was used as the main means of investigation. A phase-separated interphase spanning 9-10μm was observed for the PEI/epoxy prepreg interface. It was found that the temperature profile of the cure cycle strongly influences the formation of this interphase. Rapid formation of these relatively large interphase areas suggests that mechanisms other than diffusion are responsible for this phenomenon.


Journal of Composite Materials | 2016

Experimental and numerical analysis of drop-weight low-velocity impact tests on hybrid titanium composite laminates:

Johannes Reiner; Juan Pablo Torres; M. Veidt; Michael Heitzmann

An experimental and numerical study on low-velocity impact responses on [Ti/0/90] s hybrid titanium composite laminates (HTCLs) is presented. Different energy levels from 10 to 40 J are investigated using a drop-weight instrument and post-impact inspection. An explicit finite element implementation provides a detailed analysis of impact response in composite and titanium layers, respectively. It accounts for interfacial debonding, progressive failure in composite plies and elastic–plastic deformation in titanium. The main failure modes are experimentally and numerically found to be debonding between titanium and composite, matrix cracking and interlaminar delamination. The principal energy-absorbing mechanism is plastic dissipation of the two titanium sheets. The low cost numerical model is able to effectively predict the overall impact response and major failure modes with good accuracy.


Key Engineering Materials | 2011

Microanalysis Techniques for the Investigation of Interphases Formed between Thermoset and Thermoplastic Polymers: Scanning Electron Microscopy and Energy Dispersive X-Ray Analysis

Michael Heitzmann; Meng Hou; M. Veidt; Rowan Paton; Ron Rasch

Prepreg resin systems are typically of complex composition and require very specific manufacturing conditions. These characteristics restrict the use of some commonly used micro analysis techniques. This paper investigates the use of low acceleration voltage scanning electron microscopy and energy dispersive x-ray analysis for the characterization of diffused polymer interfaces. It is shown that, by operating at the dynamic charge balance, high resolution secondary electron images of polymer interfaces can be obtained and that conductive coating is not required. In addition, the effect of acceleration voltage on the interaction volume in EDX analysis is discussed using Monte Carlo simulation. X-ray intensity measurements in combination with afore mentioned Monte Carlo simulation is used to define practically obtainable spatial resolution limits. It is shown that by reducing the acceleration voltage below 5kV spatial resolution higher the 500nm can be obtained.


Cellulose | 2017

Inverse gas chromatography for natural fibre characterisation: dispersive and acid-base distribution profiles of the surface energy

A. Legras; A. Kondor; M. Alcock; Michael Heitzmann; R. W. Truss

Inverse Gas Chromatography (IGC) is a gas sorption technique to determine the surface energy of natural fibres. The surface energy is directly related to the thermodynamic work of adhesion and it reflects the fibre adsorption capacity and its wettability. However, natural fibres have a complex surface chemistry of numerous organic species and present physical asperities that render the surface energetically heterogeneous. Since IGC is typically performed at infinite dilution where only the higher energetic sites interact with the solvent, a single measure of surface energy is likely to be misleading as the surface energy changes with changing chemical composition. Here we present the dispersive and acid-base surface energy profiles of flax and kenaf fibres as well as continuous filament fibres produced by a dry jet, wet spinning process (cellulose B). We injected a series of n-alkanes at finite dilution to obtain the dispersive energy distribution profile at


Materials Science and Engineering: C | 2019

A biocompatible thermoset polymer binder for Direct Ink Writing of porous titanium scaffolds for bone tissue engineering

Yunhui Chen; Pingping Han; Luigi-Jules Vandi; Ali Dehghan-Manshadi; Jarrad Humphry; Damon Kent; I. Stefani; Peter D. Lee; Michael Heitzmann; Justin J. Cooper-White; Matthew S. Dargusch


Journal of Composite Materials | 2018

Fire performance of continuous glass fibre reinforced polycarbonate composites: The effect of fibre architecture on the fire properties of polycarbonate composites

Yousof M Ghazzawi; Andres F Osorio; Michael Heitzmann

30\,^{\circ }\hbox {C}


Advances in Structural Engineering | 2018

Hybrid fibre-reinforced polymer–timber thin-walled structural members

Dilum Fernando; J.G. Teng; Joseph M. Gattas; Michael Heitzmann


24th Australasian Conference on the Mechanics of Structures and Materials | 2016

Behavior of FRP confined ultra-high strength concrete columns under compression: An experimental study

S. Jiang; Dilum Fernando; J.C.M. Ho; Michael Heitzmann

30∘C and 0% RH. The acid-base contributions were determined by injection of mono polar probes (dichloromethane, ethylacetate) at the same surface coverages and applying the Van Oss method. The cellulose B fibres were the most energetically homogeneous, while the bast fibres were shown to have a higher polar component and much broader surface energy distributions than the cellulose fibres.

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M. Veidt

University of Queensland

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Meng Hou

University of Queensland

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R. W. Truss

University of Queensland

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Rowan Paton

Cooperative Research Centre

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A. Legras

University of Queensland

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Dilum Fernando

University of Queensland

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Jarrad Humphry

University of Queensland

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