Publications
548 results found
Jones M, Weiland K, Kujundzic M, et al., 2019, Waste-Derived Low-Cost Mycelium Nanopapers with Tunable Mechanical and Surface Properties, BIOMACROMOLECULES, Vol: 20, Pages: 3513-3523, ISSN: 1525-7797
- Author Web Link
- Cite
- Citations: 37
Voulgaropoulos V, Zadrazil I, Le Brun N, et al., 2019, On the link between experimentally‐measured turbulence quantities and polymer‐induced drag reduction in pipe flows, AIChE Journal, Vol: 65, Pages: 1-13, ISSN: 0001-1541
In this study, we investigate the hydrodynamics of polymer‐induced drag reduction in horizontal turbulent pipe flows. We provide spatiotemporally resolved information of velocity and its gradients obtained with particle image velocimetry (PIV) measurements in solutions of water with dissolved polyethylene oxide (PEO) of three different molecular weights, at various dilute concentrations and with flow Reynolds numbers from 35, 000 to 210, 000. We find that the local magnitudes of important turbulent flow variables correlate with the measured levels of drag reduction irrespective of the flow Reynolds number, polymer weight and concentration. Contour maps illustrate the spatial characteristics of this correlation. A relationship between the drag reduction and the turbulent flow variables is found. The effects of the polymer molecular weight, its concentration and the Reynolds number on the flow are further examined through joint probability distributions of the fluctuations of the streamwise and spanwise velocity components.
Anthony D, Nguyen S, Senokos E, et al., 2019, Hierarchical carbon aerogel modified carbon fiber composites for structural power applications, 22nd International Conference on Composite Materials 2019 (ICCM22), Publisher: Engineers Australia, Pages: 1-7
The desire to reduce overall weight in devices is a key driver for perpetual material development; the ability to combine composites with energy storage functions/capabilities which simultaneously provide structural integrity has the potential to supersede monofunctional components. To achieve this ambition, the multifunctional structure must perform both mechanical and energy storage functions sufficiently, but often there is a trade off in performance which is a significant challenge to overcome. Carbon aerogels have been shown to contribute positively to (electro-chemical double layer) capacitive performance due to an increased surface area in multifunctional carbon fiber based composite electrodes, but have also been shown to reduce mechanical properties; the addition of nanoscale reinforcers, such as carbon nanotubes, graphene or alike, with their superlative electrical and mechanical properties are proposed to address these concerns and create a truly hierarchical structure suitable for structural power applications.
Zeindlhofer V, Zehetner L, Paschinger W, et al., 2019, Computational analysis of conductivity contributions in an ionic liquid mixture of 1-ethyl-3-methylimidazolium dicyanamide and tetrafluoroborate, JOURNAL OF MOLECULAR LIQUIDS, Vol: 288, ISSN: 0167-7322
- Author Web Link
- Cite
- Citations: 10
Mautner A, Kwaw Y, Weiland K, et al., 2019, Natural fibre-nanocellulose composite filters for the removal of heavy metal ions from water, INDUSTRIAL CROPS AND PRODUCTS, Vol: 133, Pages: 325-332, ISSN: 0926-6690
- Author Web Link
- Cite
- Citations: 37
von Baeckmann C, Wilhelm H, Spieckermann F, et al., 2019, The influence of crystallization conditions on the macromolecular structure and strength of γ-polypropylene, THERMOCHIMICA ACTA, Vol: 677, Pages: 131-138, ISSN: 0040-6031
- Author Web Link
- Cite
- Citations: 8
Jones MP, Lawrie AC, Huynh TT, et al., 2019, Agricultural by-product suitability for the production of chitinous composites and nanofibers utilising <i>Trametes versicolor</i> and <i>Polyporus brumalis</i> mycelial growth, PROCESS BIOCHEMISTRY, Vol: 80, Pages: 95-102, ISSN: 1359-5113
- Author Web Link
- Cite
- Citations: 39
Jalalian M, Jiang Q, Coulon A, et al., 2019, Mechanically whipped phenolic froths as versatile templates for manufacturing phenolic and carbon foams, MATERIALS & DESIGN, Vol: 168, ISSN: 0264-1275
- Author Web Link
- Cite
- Citations: 24
Fazli Wan Nawawi WM, Lee KY, Kontturi E, et al., 2019, Chitin nanopaper from mushroom extract: natural composite of nanofibers and glucan from a single biobased source, ACS Sustainable Chemistry and Engineering, Vol: 7, Pages: 6492-6496, ISSN: 2168-0485
An isolation method with mild mechanical agitation and no acidic extraction step from a mushroom substrate resulted in chitin nanofibers (ChNFs) with large shares of retained glucans (50-65%). The subsequent chitin nanopapers exhibited exceptionally high tensile strengths of >200 MPa and moduli of ca. 7 GPa, which were largely attributed to the preserved glucans in the mixture, imparting a composite nature to the nanopapers. The isolation method for ChNFs is notably different from the conventional process with crustacean chitin sources that do not incorporate glucans and where an acidic extraction step for the removal of minerals must always be included.
Mautner A, Fortea-Verdejo M, Bismarck A, 2019, Energy efficient nanocellulose foam coating on cellulosic textiles for water filtration membranes, National Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727
Mautner A, Janesch J, Bismarck A, 2019, Fungal chitosan-glucan in water remediation applications, National Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727
Kontturi E, Lee K-Y, Bismarck A, 2019, Nanocellulose: What can go wrong?, National Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727
Mayer F, Mautner A, Lee K-Y, et al., 2019, Hybridization of nanocelluloses for improved nanopaper properties, National Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727
Kondor A, Mautner A, Lee K-Y, et al., 2019, Challenges on specific surface area analysis of cellulosic materials, National Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727
Fortea-Verdejo M, Mautner A, Bismarck A, 2019, Foaming nanocellulose for coating applications, National Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727
Lee K-Y, Murakami R, Bismarck A, 2019, Cellulose fibril emulsifiers: Interesting and versatile, National Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727
Weiland K, Mautner A, Arteaga JL, et al., 2019, Elephantidae manure and biogas residue as potential raw material for the extraction of cellulose, National Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727
Jalalian M, Jiang Q, Bismarck A, 2019, Air Templated Macroporous Epoxy Foams with Silica Particles as Property-Defining Additive, ACS APPLIED POLYMER MATERIALS, Vol: 1, Pages: 335-343, ISSN: 2637-6105
- Author Web Link
- Cite
- Citations: 15
Mautner A, Kobkeatthawin T, Mayer F, et al., 2019, Rapid Water Softening with TEMPO-Oxidized/Phosphorylated Nanopapers, NANOMATERIALS, Vol: 9
- Author Web Link
- Cite
- Citations: 19
Zainol Abidin MS, Herceg T, Greenhalgh ES, et al., 2019, Enhanced fracture toughness of hierarchical carbon nanotube reinforced carbon fibre epoxy composites with engineered matrix microstructure, Composites Science and Technology, Vol: 170, Pages: 85-92, ISSN: 0266-3538
Fibre reinforced hierarchical composites further reinforced with up to 25 wt.% of carbon nanotubes (CNTs) were manufactured using a wet powder impregnation route. Microstructural heterogeneity in the matrix of these laminates was engineered during wet powder impregnation to produce CNTs rich regions with spatial separation. The Mode I fracture toughness of these heterogeneous hierarchical composites increased by 41% and 26% compared to that of baseline carbon fibre epoxy composites and hierarchical composites with homogeneously distributed CNTs throughout the matrix with similar CNT content, respectively. Increased crack path tortuosity was observed to contribute to this increase in fracture toughness. The interlaminar shear strength was unaffected by the matrix microstructural heterogeneity.
Liu B, Liu C, De Luca H, et al., 2019, Synthesis of epoxidized poly(ester carbonate)-b-polyimide-b-poly(ester carbonate): reactive single-walled carbon nanotube dispersants enable synergistic reinforcement around multi-walled nanotube-grafted carbon fibers, Polymer Chemistry, Vol: 10, Pages: 1324-1334, ISSN: 1759-9954
Polyimides (PI) generally have a high affinity for single-walled carbon nanotubes (SWNTs), but they suffer from poor solubility in most low boiling point organic solvents and low compatibility with common resins (such as epoxy) used in composites, limiting their suitability as dispersants. PI block copolymer systems containing reactive poly(ester carbonate)s have not yet been reported and are expected to act as effective reactive dispersing agents of SWNTs. Herein, PI-derived block copolymers are synthesized via ring-opening copolymerization of lactide (LA) (a control monomer) and allyl-bearing 2-methyl-2-(allyloxycarbonyl)-propylene carbonate (MAC) from the OH-terminal ends of the PI block to produce PLA-PI-PLA (TB1, a control) and PMAC-PI-PMAC (TB2). The allyl pendant group of TB2 allows further facile functionalization to form a third series of epoxidized (EP) derivatives, i.e. PMACEP-block-PI-block-PMACEP (TB3). TB3 copolymer when mixed with a conventional structural epoxy resin forms blends that do not show inferior tensile properties compared with the epoxy, which is unusual. Furthermore, the mixing solvent tetrahydrofuran (THF) can be readily evaporated off after forming the blends. TB3-dispersed (2 wt%) SWNTs added to epoxy increased the tensile strength, modulus, and elongation at break of the resulting nanocomposite films by 40%, 34%, and 26% respectively, compared to the baseline epoxy resin. Furthermore, when TB3b triblock-dispersed SWNTs in epoxy were combined with fuzzy carbon fibers, i.e. carbon nanotube-grafted-carbon fibers (CNT-g-CF), a synergistic interfacial strength reinforcement was observed, together with shifting of the failure mode from the matrix interphase to the carbon fiber-grafted nanotube interface. The ultimate interfacial shear strength between the TB3-dispersed SWNT-epoxy matrix and the fuzzy carbon fibers (i.e., fibers having carbon nanotubes grown on them) measured via single fiber pull-out tests was 100 MPa, which was ca. 11% imp
Chen G, Lee K-Y, Bismarck A, et al., 2019, Cellulose materials and methods of making and using same, US10,988,897
Mautner A, Weiland K, Bismarck A, 2019, Cellulose nanopaper composites based on nanocellulose from elephant manure
© CCM 2020 - 18th European Conference on Composite Materials. All rights reserved. Nanocelluloses (NFC) gained substantial attention in recent years as reinforcement of composite materials due to their excellent properties. One promising approach to yield high fibre volume fraction NFC composites is to laminate nanopapers. Thereby, the characteristics of the nanopapers directly determine the properties of the composites, hence, excellent mechanical properties of the nanopapers are desired. Nonetheless, aiming at ecologically sound solutions, also the raw material of the NFC needs to be considered. In this regard, utilizing agricultural waste rather than high-grade resources (wood) as base material would be vital. We have identified elephant manure to be a suitable precursor for the preparation of NFC, for elephants digest only about 35 % of their diet. Accordingly, their excrements contain large quantities of fibrous cellulosic material, whereby the ingestion and digestion already initiates fibre break-down. Thus, utilizing the elephant as first-stage bioreactor for the defibrillation of cellulose fibres by mechanical and chemical means constitutes an energy-efficient approach for the production of NFC. We demonstrate that by chemical purification of elephant manure, cellulose nanofibrils can be isolated from which papers were produced that had better mechanical properties than most common unmodified NFC nanopapers thus being ideal candidates for the preparation of nanopaper composites.
Yousefi N, Maples HA, James T, et al., 2019, Manufacturing affordable composites using solid epoxy resins
© CCM 2020 - 18th European Conference on Composite Materials. All rights reserved. We have investigated the use of solid epoxy resins in composite manufacturing. Solid epoxy resins are mainly used as protective coatings e.g. in marine applications, and have had limited use as composite matrices. Solid epoxy formulations are typically much cheaper than liquid epoxy resins commonly used in composite production. The development of a novel manufacturing method with solid epoxies could therefore lower the overall cost of high performance composites. Different resins were formulated by mixing solid epoxies, hardeners and accelerators at elevated temperatures. These mixtures were then ground into uncured, resin powders. The resin powders were applied directly onto carbon fibers, which were then heated, infused with the melted resin system and cured (curing times of <10 min were achieved by using accelerators). The laminates manufactured without accelerator had competitive mechanical properties (flexural modulus, 80 GPa; flexural strength, 1270 MPa) when compared against other high-performance composites. However, the addition of accelerator led to higher void content in the matrix, which affected the mechanical composite properties. In order to prevent a high void content flow media was successfully introduced into the process.
Mautner A, Weiland K, Bismarck A, 2019, Cellulose nanopaper composites based on nanocellulose from elephant manure
© CCM 2020 - 18th European Conference on Composite Materials. All rights reserved. Nanocelluloses (NFC) gained substantial attention in recent years as reinforcement of composite materials due to their excellent properties. One promising approach to yield high fibre volume fraction NFC composites is to laminate nanopapers. Thereby, the characteristics of the nanopapers directly determine the properties of the composites, hence, excellent mechanical properties of the nanopapers are desired. Nonetheless, aiming at ecologically sound solutions, also the raw material of the NFC needs to be considered. In this regard, utilizing agricultural waste rather than high-grade resources (wood) as base material would be vital. We have identified elephant manure to be a suitable precursor for the preparation of NFC, for elephants digest only about 35 % of their diet. Accordingly, their excrements contain large quantities of fibrous cellulosic material, whereby the ingestion and digestion already initiates fibre break-down. Thus, utilizing the elephant as first-stage bioreactor for the defibrillation of cellulose fibres by mechanical and chemical means constitutes an energy-efficient approach for the production of NFC. We demonstrate that by chemical purification of elephant manure, cellulose nanofibrils can be isolated from which papers were produced that had better mechanical properties than most common unmodified NFC nanopapers thus being ideal candidates for the preparation of nanopaper composites.
Barkan-Öztürk H, Menner A, Bismarck A, 2019, Emulsion templated macroporous polymer as micromixer
Microfluidic mixing technology grew rapidly in the past few years due to its many advantages over the macro-scale mixing, especially the ability to use small amounts of internal volume, the fast and controllable mixing process and reactions with very fast kinetic during the laminar flow. By using obstacles in the micromixer, the mixing length and the contact area between the species have been increased. Therefore, the channel geometry and its surface property have great importance to reach a satisfactory mixing results. Since poly(-merised)High Internal Phase Emulsions (polyHIPEs) have more than 74% porosity and their pores are connected each other with pore throats, which cause high permeability, they are ideal candidate to build a micromixer. The HIPE precursor is commonly produced by using an overhead stirrer to obtain relatively large amount of emulsion in batch process. However, we will demonstrate that a desired amount of emulsion can be prepared continuously with micromixer build from polyHIPE, and such HIPE can subsequently be employed as ink in 3D printing process.
Menner A, Rusakov D, Bismarck A, 2019, Pushing lot`s of air into peek and peKK
© CCM 2020 - 18th European Conference on Composite Materials. All rights reserved. Thermally induced phase separation (TIPS) of polymer solutions at low temperatures is a common method to produced polymer foams. However, so far it has not been adopted for manufacturing monolithic PEEK and PEKK foams. Here we present our first high porosity PEEK and PEKK foams obtained by a modified TIPS process, which is based on the temperature dependent solubility of PEEK and PEKK in specific aprotic high boiling point solvents like diphenylketone. After dissolving various amount of polymer, we adjust the morphology of the resulting PEEK or PEKK foams by changing process parameters like the cooling rate; homogeneous networks of highly interconnected pores with pore sizes of approx. 1-3 µm have been achieved. Most importantly, however, for the first time, we have been able to produce mechanically strong, macroporous PEEK and PEKK monoliths with porosities of up to 90%.
Yousefi N, Maples HA, James T, et al., 2019, Manufacturing affordable composites using solid epoxy resins
We have investigated the use of solid epoxy resins in composite manufacturing. Solid epoxy resins are mainly used as protective coatings e.g. in marine applications, and have had limited use as composite matrices. Solid epoxy formulations are typically much cheaper than liquid epoxy resins commonly used in composite production. The development of a novel manufacturing method with solid epoxies could therefore lower the overall cost of high performance composites. Different resins were formulated by mixing solid epoxies, hardeners and accelerators at elevated temperatures. These mixtures were then ground into uncured, resin powders. The resin powders were applied directly onto carbon fibers, which were then heated, infused with the melted resin system and cured (curing times of <10 min were achieved by using accelerators). The laminates manufactured without accelerator had competitive mechanical properties (flexural modulus, 80 GPa; flexural strength, 1270 MPa) when compared against other high-performance composites. However, the addition of accelerator led to higher void content in the matrix, which affected the mechanical composite properties. In order to prevent a high void content flow media was successfully introduced into the process.
Menner A, Rusakov D, Bismarck A, 2019, Pushing lot`s of air into peek and peKK
Thermally induced phase separation (TIPS) of polymer solutions at low temperatures is a common method to produced polymer foams. However, so far it has not been adopted for manufacturing monolithic PEEK and PEKK foams. Here we present our first high porosity PEEK and PEKK foams obtained by a modified TIPS process, which is based on the temperature dependent solubility of PEEK and PEKK in specific aprotic high boiling point solvents like diphenylketone. After dissolving various amount of polymer, we adjust the morphology of the resulting PEEK or PEKK foams by changing process parameters like the cooling rate; homogeneous networks of highly interconnected pores with pore sizes of approx. 1-3 µm have been achieved. Most importantly, however, for the first time, we have been able to produce mechanically strong, macroporous PEEK and PEKK monoliths with porosities of up to 90%.
Jones M, Weiland K, Kujundzic M, et al., 2019, Sustainable mycelium-derived chitinous thin films
Mycelium, the vegetative growth of filamentous fungi, has attracted increasing commercial and academic interest in recent years due to its ability to upcycle agricultural and industrial wastes into low-cost, environmentally sustainable composite materials. Mycelium composites, comprising a mycelium matrix formed through natural fungal growth and a waste-based filler have displayed significant potential as biodegradable alternatives to synthetic foams for a range of applications including packaging, insulation and construction. The primary limitation of these materials is their poor mechanical properties, originating from the weak organic constituents they comprise, incomplete fungal digestion and bonding and the presence of non-structural elements in hyphal filaments, such as cytoplasm, proteins and lipids. This study aimed to improve the mechanical performance of mycelium materials by isolating and hot-pressing the structural polymers chitin and glucan, obtained via mild chemical extraction of fungal mycelium grown on sugarcane by-product molasses. The resulting homogenous material constituted a cheap, environmentally sustainable thin film with much higher tensile strength than existing mycelium materials, potentially suitable for applications including coatings, membranes and paper.
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.