Alexander Bismarck

University of Vienna | UniWien · Materials Chemistry and Research

Poly(ether ketone ketone) (PEKK) is a semicrystalline high‐performance polymer with exceptional mechanical properties, high continuous operation temperature, and is insoluble in most common solvents. Porous PEKK, desired for biomedical applications, is produced by a high‐temperature thermally induced phase separation process using PEKK solutions in...

Nanocellulose papers offer high tensile strength and modulus but suffer from drawbacks such as their brittle nature. Many attempts to alleviate these disadvantages were reported, with most of them being time and/or resource-intensive or requiring additional chemical or mechanical (pre)treatments, modification, or the use of additives. We show that...

Dragline silk of Trichonephila spiders has attracted attention in various applications. One of the most fascinating uses of dragline silk is in nerve regeneration as a luminal filling for nerve guidance conduits. In fact, conduits filled with spider silk can measure up to autologous nerve transplantation, but the reasons behind the success of silk...

Inverse Gas Chromatography (IGC) is an important technique for characterization of solids. Determining the specific retention volume of the injected probe molecule is the basis of the analysis for all the physico-chemical properties that the technique can determine, most importantly in Heat of Sorption, Glass Transition Temperature, Gibbs Adsorptio...

Growing demand for animal products caused by a growing population and improved living-standards also yields large quantities of manure constituting an eminent problem. Herbivore manure can be utilized as fertilizer or for biogas production, which, however, disregards the full potential of manure as feedstock for lignocellulosics. Thus, an integrate...

The long-term drag reduction capability of poly(ethylene oxide) with a nominal molar weight of 𝑀𝑤=4×10^6 g/mol dissolved in water was investigated in a pilot-scale pipe flow device (inner diameter of test section 26 mm) at a Reynolds number of 10^5. A total loss of the initially high (75%) drag reduction capability was observed over a flow distance...

Nanofibrillated cellulose (NFC) has key applications in composites, water filters and emulsifiers. The affinity of NFC to water is a challenge, as it negatively influences its integrity. Lignin, a major component of plant biomass, is a natural hydrophobiser. Anaerobic digestion (AD) of biomass to produce biomethane allows to up-concentrate lignin i...

Treatment of polluted water is an important task to secure access to clean water also for future generations. Filters are an efficient means to reject various pollutants on a wide range of size scales either by size-exclusion or electrostatic interaction, respectively. Commonly, filters and membranes from various synthetic materials are employed fo...

Hydrophobically modified associating polymers could be effective drag-reducing agents containing weak "links" which after degradation can reform, protecting the polymer backbone from fast scission. Previous studies using hydrophobically modified polymers in drag reduction applications used polymers with M w ≥ 1000 kg/mol. Homopolymers of this high...

We demonstrate a simple, versatile one-pot approach for the preparation of particle stabilised soft templates and macroporous polymer materials from them. This approach allows for the rapid fabrication (in a few minutes rather than hours) of large amounts of Pickering emulsion templates by performing the synthesis of mineral nanoparticle stabiliser...

Porous polymers offer desirable properties for heterogeneous catalysis, such as excellent stability, high active site density, and reusability. However, their synthesis is often complicated, requiring expensive reagents and laborious synthetic processes. We produce organophosphorus functionalized polyHIPEs by the polymerization of particle and surf...

From plants tracking the sun to the aerodynamics of bird wings, shape change is key to the performance of natural structures. After years of reliance on mechanical joints, human engineering now focuses on improving aerodynamic efficiency through smooth, full form changes in material geometry, achieved using technologies such as morphing composites....

Immediate and widespread changes in energy generation and use are critical to safeguard our future on this planet. However, while the necessity of renewable electricity generation is clear, the aviation, transport and mobility, chemical and material sectors are challenging to fully electrify. The age-old Fischer-Tropsch process and natural gas indu...

Continuous liquid-liquid extraction and separation of 4-aminoacetophenone, a product of the hydrogenation of 4-nitroacetophenone, was performed within emulsion templated macroporous polymer (polyHIPE) extraction units using a miniaturized gravity-based settler. PolyHIPEs with interconnected and tailorable macroporous structures are effective microm...

Due to its unique properties, nano fibrillated cellulose (NFC) has been a popular topic of research in recent years. Nevertheless, literature assessing environmental impacts of NFC production is scarce, especially for using other starting materials than wood pulp. Hence, in this study, a new approach of cascaded use of manure to produce biogas and...

A tubular co-flow reactor to produce macroporous polymer beads by polymerization of medium and high internal phase emulsion (M/HIPE) templates was developed. This reactor allows for improved production rates compared to tubing based microfluidic devices. Water-in-oil (W/O) M/HIPEs, containing methyl methacrylate (MMA) and ethylene glycol dimethacry...

The interfacial properties of carbon fiber (CF) reinforced thermoplastic composites depend strongly on the wettability and surface characteristics of the reinforcing fibers, and their compatibility with a chosen matrix. The interface between conventional fibers and thermoplastic matrices is generally weak, due to a lack of specific chemical interac...

Uncured solid bisphenol-A epoxy resins containing up to 20 wt% carbon nanotubes (CNTs) were prepared using melt blending in a high shear mixer. The extrudate was ground to produce fine nanocomposite (NC) powders. This simple method produced well-dispersed NC, with CNT agglomerate sizes below 1 μm. Consolidated NCs displayed improved tensile moduli...

Uncured solid bisphenol-A epoxy resins containing up to 20 wt% carbon nanotubes (CNTs) were prepared using melt blending in a high shear mixer. The extrudate was ground to produce fine nanocomposite (NC) powders. This simple method produced well-dispersed NC, with CNT agglomerate sizes below 1 μm. Consolidated NCs displayed improved tensile moduli...

Investigations on lithographically formed cavities of surface-imprinted polymers (SIP) can help to gain deeper understanding on cell recognition with SIPs: it is known that surface topography and biomolecules transferred during surface imprinting contribute to cell adhesion. In this work, SIPs synthesized via two different imprinting techniques, na...

List of Figures Figure S1. Tensile stress-strain curves for neat resorcinol-formaldehyde-latex (RFL) matrix containing no fibres Figure S2. High resolution (a) C1s, (b) O1s and (c) N1s XPS spectra detailing the surface composition of AGY-S2 glass fibres compared to unsized AS4D and T700GC-91 and sized T700GC-31E,-41E as well as desized (ultrasound-...

Radical innovations for all aircraft systems and subsystems are needed for realizing future carbon-neutral aircraft, with hybrid-electric aircraft due to be delivered after 2035, initially in the regional aircraft segment of the industry. Electrical energy storage is one key element here, demanding safe, energy-dense, lightweight technologies. Comb...

Poly (ether ether ketone) (PEEK) has a high continuous service temperature, excellent mechanical properties, and good solvent and abrasion resistance, which can be further improved through the addition of carbon nanotubes (CNTs). CNT-PEEK nanocomposites are promising matrices for continuous carbon fibre composites; powder processing can mitigate th...

Macroporous polymers and nanocomposites remain popular materials due to their low densities and unique interconnected pore structures. The determination of mechanical properties in relevant loading conditions, such as shear, remains largely underexplored due to the comparative complexity of such analysis compared to simple compression tests. We inv...

The use of carbon fibres is being explored in synchronous belts due to their excellent mechanical properties, chemical and dimensional stability. However, poor adhesion between fibres and the common rubber-fibre adhesive resorcinol-formaldehyde-latex (RFL) compromises load transfer between these constituents. We examined the influence of surface ch...

There are a range of promising applications for devices that can convert mechanical energy from their local environment into useful electrical energy. Here, mechanical energy harvesting devices have been developed to scavenge low-frequency energy from regular biomotion such as joint movement and heel strike. Specifically, these harvesters exploit n...

Structural supercapacitors can both carry load and store electrical energy. An approach to build such devices is to modify carbon fibre surfaces to increase their specific surface area and to embed them into a structural electrolyte. We present a way to coat carbon fibres with graphene nanoplatelets by electrophoretic deposition in water. The effec...

Porous polyepoxides are attractive materials for a range of applications. Liquid foam precursors can be net-shaped by moulding. We report preparation of permeable polyepoxide, Araldite®2020, foams with porosities in the range of 45–60% from surfactant-stabilised W/O medium internal phase emulsion templates. Alteration of internal phase volume ratio...

The demand for animal products has significantly increased over the past decades as a result of the growing population and the heightened standards of living. Increased livestock farming does not only yield desired products but also significant quantities of wastes, particularly manure whose storage and application are being monitored with a tighte...

We evaluated the influence of blending various renewable polymer grades and amounts to allow for high stretchability during stretching at 800 mm/s to produce polymer tapes with high Young’s moduli E and yield stress σy similar to industrial production of non-degradable synthetic polymers. Renewable polymer blends based on TPS, PBAT, and PLA with hi...

Micromixers made from emulsion templated macroporous polymers (poly-Pickering-HIPEs) were used to continuously produce polymerizable high internal phase emulsions (HIPE) by injecting a monomer containing continuous phase and aqueous internal phase into micromixers. The interconnected and complex flow path through poly-Pickering-HIPE micromixers res...

Interleaving the plies of carbon fibre reinforced epoxy composites with thermoplastic interleaves have previously been shown to enable these composites to display controllable stiffness and shape memory properties. However, the incorporation of unreinforced thermoplastic interleaves leads to a decrease in flexural modulus of the interleaved composi...

Micromixers were fabricated from emulsion-templated macroporous polymers, known as polymerizing high internal-phase emulsions (polyHIPEs). Micromixers are mixing elements containing submillimeter channels, in which mixing occurs by molecular diffusion in the laminar flow regime. PolyHIPEs possess an interconnected pore structure with connected chan...

Volumetric N 2 adsorption at −196°C is generally accepted as "gold standard" for estimating the Brunauer-Emmet-Teller (BET) surface area of nanocellulose. It is unclear however, whether the BET surface area of nanocellulose obtained at such low temperatures and pressures is meaningful at an absolute sense, as nanocellulose is used at ambient temper...

On the mechanical degradation of PEO utilised as a drag reducing agent. The long-term experiment was perfomed in a pilot scale flow device (ViEDRA) at Re~100000.

Birch (Betula pendula Roth.) and beech (Fagus sylvatica L.) solid wood and plywood were overmolded with polyamide 6 (PA 6) and polypropylene (PP) to investigate their mechanical properties and interfacial adhesion. In the case of PA 6, maximum tensile shear strengths values of more than 8 to 9 MPa were obtained for birch and beech, respectively. Th...

3D Printing, utilizing a layer-by-layer deposition of materials, is advantageous to manufacture parts as it involves fewer process steps, provides great flexibility for prototyping, especially of complex parts, and has low material waste. Yet, the mechanical properties of 3D printed parts have always been a concern due to the weak inter-layer bondi...

Polyetheretherketone (PEEK) is a high-performance semi-crystalline thermoplastic polymer with outstanding mechanical properties, high thermal stability, resistance to most common solvents, and good biocompatibility. A high temperature thermally induced phase separation technique was used to produce PEEK foams with controlled foam density from PEEK...

Cellulose nanopapers provide diverse, strong and lightweight templates prepared entirely from sustainable raw materials, cellulose nanofibers (CNFs). Yet the strength of CNFs has not been fully capitalized in the resulting nanopapers and the relative influence of CNF strength, their bonding, and biological origin to nanopaper strength are unknown....

Macroporous polymers can be produced by curing liquid foam templates, which consist of air bubbles mechanically beaten into a liquid monomer phase. However, non-aqueous foam templates containing hydrophobic monomers as liquid phase are difficult to produce, as they cannot be stabilised by reducing their surface tension. In this perspective, we revi...

Membranes and filters are essential devices, both in the laboratory for separation of media, solvent recovery, organic solvent and water filtration purposes, and in industrial scale applications, such as the removal of industrial pollutants, e.g. heavy metal ions, from water. Due to their solvent stability, biologically sourced and renewable membra...

Flexible epoxy foams were successfully prepared by curing medium internal phase emulsions (MIPEs) with a continuous organic phase containing epoxy resin and hardener, surfactant and carbon nanotubes and an aqueous internal phase. Curing the MIPEs at ambient temperature resulted in interconnected polyepoxide foams with average pore size of about 10...

Access to clean potable water is increasingly becoming a struggle for whole humankind, thus water treatment to remediate wastewater and fresh water sources is an important task. Pollutants in the nanoscale, such as viruses and macromolecules, are usually removed by means of membrane filtration processes, predominantly nanofiltration or ultrafiltrat...

We hybridised lignocellulose microfibres with a fungal derived nanoscale chitin-β-glucan network produce hydrophobic papers with improved tensile properties.

Thermosetting resins were formulated by mixing solid epoxy components, hardener and accelerator at elevated temperature. These mixtures were ground into uncured, solid resin powders and dispensed onto carbon fibres using a powder printer prior to vacuum curing. Using accelerators reduced curing time from 8 h to 16 min. Manufactured cross-ply carbon...

A solid epoxy resin formulation containing 2.5 wt % carbon nanotubes is 3D printed into self-standing parts, which after thermal curing result in CNTs/epoxy nanocomposites with mechanical properties attractive for heavy-duty applications.

A simple kitchen mixer and skills to whip cream can be useful to manufacture highly functional polymer foams with control over their structures. In the 1930s, researchers began to whip or inject gas into monomers or polymer suspensions to produce liquid foams, which served as templates to be solidified to polymer foams. Besides the “simplicity” of...

Safe, light, and high-performance engineering structures may be generated by adopting composite materials with stable damage process (i.e., without catastrophic delamination). Interlayer hybrid composites may fail stably by suppressing catastrophic interlayer delamination. This paper provides a detailed analysis of delamination occurring in poly(ac...

Fungi-derived leather substitutes are an emerging class of ethically and environmentally responsible fabrics that are increasingly meeting consumer aesthetic and functional expectations and winning favour as an alternative to bovine and synthetic leathers. While traditional leather and its alternatives are sourced from animals and synthetic polymer...

Nano-engineered fibre/matrix interfaces can improve state-of-the-art fibre-reinforced composites. Grafting carbon nanotubes (CNTs) to high temperature quartz glass fibres produces “hairy” or “fuzzy” fibres, which combine reinforcements at micrometre and nanometre length scales. Fuzzy quartz fibres were produced continuously, reel-to-reel, on whole...

Fungal chitin is attracting commercial and academic interest as a cheap, renewable, easily isolated and abundant alternative to crustacean chitin. Being covalently decorated with β-glucan, fungal chitin exhibits a native nanocomposite architecture that varies in fibre diameter and chitin to β-glucan ratio from species to species, resulting in mecha...

Macroporous, low‐density polyetheretherketone, polyetherketoneketone, and polyetherimide foams are produced using a high‐temperature, thermally induced phase separation method. A high‐boiling‐point solvent, which is suitable to dissolve at least 20 wt% of these high‐performance polymers at temperatures above 250 °C, is identified. The foam morpholo...

The influence of the molecular weight (MW) of isotactic polypropylene (iPP) on the activation energy of the α-transition (EAα) and the stretching behaviour was investigated and correlations drawn. Mechanical relaxations in polyolefins are related to the mobility of polymer chains. The temperature of the α-transition in polyolefins increases with te...

The image representing article number 2000467 by Martin Kaltenbrunner and co‐workers shows the mixing of the two phases that form a polyHIPE, a process in which UV‐curable monomers and an electrolyte solution are brought together, to form a highly porous, ion conductive structure. The use of such polyHIPEs as high‐performance separators in stretcha...

Powering soft embodiments of robots, machines and electronics is a key issue that impacts emerging human friendly forms of technologies. Batteries as energy source enable their untethered operation at high power density but must be rendered elastic to fully comply with (soft) robots and human beings. Current intrinsically stretchable batteries typi...

Utilizing high-performance cellulose nanopapers as 2D-reinforcement for polymers allows for realizing high-loading-fraction (80 vol-%), high-performance (strength > 150 MPa, modulus > 10 GPa) laminated nanopaper reinforced epoxy composites. Such cellulose nanopapers are inherently dense, which renders them difficult to be impregnated with the epoxy...

An integrated gaseous transport apparatus was designed not only to measure permeability (by the pressure rise technique) but also to study both steady state and (importantly) transient diffusion of oxygen in nitrogen in the pores of the porous material. The apparatus allows for the characterisation of porous media with a wide range of permeabilitie...

An integrated gaseous transport apparatus was designed not only to measure permeability (by the pressure rise technique) but also to study both steady state and (importantly) transient diffusion of oxygen in nitrogen in the pores of the porous material. The apparatus allows for the characterisation of porous media with a wide range of