478 results found
Stadlmann A, Mautner A, Pramreiter M, et al., 2021, Interfacial Adhesion and Mechanical Properties of Wood-Polymer Hybrid Composites Prepared by Injection Molding, POLYMERS, Vol: 13
Kondor A, Santmarti A, Mautner A, et al., 2021, On the BET surface area of nanocellulose determined using volumetric, gravimetric and chromatographic adsorption methods, Frontiers in Chemical Engineering, ISSN: 2673-2718
Volumetric N2 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 temperature and pressure. In this work, a systematic evaluation of the BET surface area of nanocellulose using a highly crystalline bacterial cellulose (BC) as model nanocellulose was undertaken to achieve a comprehensive understanding of the limitations of BET method for nanocellulose. BET surface area obtained using volumetric N2 adsorption at –196 °C was compared with the BET surface area acquired from gravimetric experiments using n-octane adsorption measured using dynamic vapour sorption (DVS) and n-octane adsorption determined by inverse gas chromatography (iGC), both at 25 °C. It was found that the BET surface area calculated from volumetric N2 adsorption data was 25% lower than that of n-octane adsorption at 25 °C obtained using DVS and iGC adsorption methods. These results supported the hypothesis that the BET surface area of nanocellulose is both a molecular scale (N2 vs n-octane, molecular cross section of 0.162 nm2 vs 0.646 nm2) and temperature (–196 °C vs 25 °C) dependent property. This study also demonstrates the importance of selecting appropriate BET pressure range based on established criteria and would suggest that the room temperature gravimetric measurement is more relevant for many nanocellulose applications.
Rusakov D, Menner A, Spieckermann F, et al., 2021, Morphology and properties of foamed high crystallinity PEEK prepared by high temperature thermally induced phase separation, JOURNAL OF APPLIED POLYMER SCIENCE, Vol: 139, ISSN: 0021-8995
Weiland K, Jones MP, Zinsser F, et al., 2021, Grow it yourself composites: delignification and hybridisation of lignocellulosic material using animals and fungi, GREEN CHEMISTRY, Vol: 23, Pages: 7506-7514, ISSN: 1463-9262
Kontturi KS, Lee K-Y, Jones MP, et al., 2021, Influence of biological origin on the tensile properties of cellulose nanopapers, CELLULOSE, Vol: 28, Pages: 6619-6628, ISSN: 0969-0239
Jiang Q, Bismarck A, 2021, A perspective: Is viscosity the key to open the next door for foam templating?, REACTIVE & FUNCTIONAL POLYMERS, Vol: 162, ISSN: 1381-5148
Zhang H, Huang T, Jiang Q, et al., 2021, Recent progress of 3D printed continuous fiber reinforced polymer composites based on fused deposition modeling: a review, JOURNAL OF MATERIALS SCIENCE, Vol: 56, Pages: 12999-13022, ISSN: 0022-2461
Eichelter J, Wilhelm H, Mautner A, et al., 2021, High-Velocity Stretching of Renewable Polymer Blends, JOURNAL OF POLYMERS AND THE ENVIRONMENT, Vol: 29, Pages: 3509-3524, ISSN: 1566-2543
Yousefi N, Evans AD, Harper LT, et al., 2021, Solid epoxy resin systems for automated composite manufacturing, COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING, Vol: 142, ISSN: 1359-835X
Yousefi N, Jones M, Bismarck A, et al., 2021, Fungal chitin-glucan nanopapers with heavy metal adsorption properties for ultrafiltration of organic solvents and water, CARBOHYDRATE POLYMERS, Vol: 253, ISSN: 0144-8617
Jiang Q, Zhang H, Rusakov D, et al., 2021, Additive Manufactured Carbon Nanotube/Epoxy Nanocomposites for Heavy-Duty Applications, ACS APPLIED POLYMER MATERIALS, Vol: 3, Pages: 93-97, ISSN: 2637-6105
Mautner A, Bismarck A, 2021, Bacterial nanocellulose papers with high porosity for optimized permeance and rejection of nm-sized pollutants, CARBOHYDRATE POLYMERS, Vol: 251, ISSN: 0144-8617
Marino SG, Mayer F, Bismarck A, et al., 2020, Effect of Plasma-Treatment of Interleaved Thermoplastic Films on Delamination in Interlayer Fibre Hybrid Composite Laminates, POLYMERS, Vol: 12
Nawawi WMFW, Jones MP, Kontturi E, et al., 2020, Plastic to elastic: Fungi-derived composite nanopapers with tunable tensile properties, COMPOSITES SCIENCE AND TECHNOLOGY, Vol: 198, ISSN: 0266-3538
De Luca H, Anthony D, Greenhalgh E, et al., 2020, Piezoresistive structural composites reinforced by carbon nanotube-grafted quartz fibres, Composites Science and Technology, Vol: 198, Pages: 1-12, ISSN: 0266-3538
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 tows, in an open chemical vapour deposition reactor. The resulting uniform coverage of 200 nm long CNTs increased the interfacial shear strength with epoxy (90.3 ± 2.1 MPa) by 12% compared to the commercially-sized counterpart, as measured by single fibre pull-out tests. The improved interfacial properties were confirmed at the macroscale using unidirectional hierarchical bundle composites, which exhibited a delayed onset of fibre/matrix debonding. Although the quartz fibres are electrically insulating, the grafted CNT create a conductive path, predominantly parallel to the fibres. To explore the applicability for structural health monitoring, the resistivity was recorded in situ during mechanical testing, and correlated with simultaneous acoustic emission data. The baseline resistivity parallel to the fibres (ρ0 = 3.9 ± 0.4 × 10−1 Ω m) displayed a linear piezoresistive response (K = 3.64) until failure at ca. 2.1% strain, also referred to as "gauge factor”, a two-fold improvement over traditional resistance strain gauges (e.g. constantan). Hierarchical, fuzzy quartz fibres, therefore, simultaneously enhance both structural and sensing performance, offering multifunctional opportunities in large composite parts.
San Manley S, Steindl P, Hewitt GF, et al., 2020, An integrated method for measuring gas permeability and diffusivity of porous solids, CHEMICAL ENGINEERING SCIENCE, Vol: 223, ISSN: 0009-2509
Eichelter J, Wilhelm H, Eder A, et al., 2020, Influence of the alpha-relaxation on the high-velocity stretchability of isotactic polypropylene, POLYMER, Vol: 200, ISSN: 0032-3861
Rusakov D, Menner A, Bismarck A, 2020, High-Performance Polymer Foams by Thermally Induced Phase Separation, MACROMOLECULAR RAPID COMMUNICATIONS, Vol: 41, ISSN: 1022-1336
Danninger D, Hartmann F, Paschinger W, et al., 2020, Stretchable Polymerized High Internal Phase Emulsion Separators for High Performance Soft Batteries, ADVANCED ENERGY MATERIALS, Vol: 10, ISSN: 1614-6832
Nawawi WMFW, Lee K-Y, Kontturi E, et al., 2020, Surface properties of chitin-glucan nanopapers from Agaricus bisporus, International Journal of Biological Macromolecules, Vol: 148, Pages: 677-687, ISSN: 0141-8130
The structural component of fungal cell walls comprises of chitin covalently bonded to glucan; this constitutes a native composite material (chitin-glucan, CG) combining the strength of chitin and the toughness of glucan. It has a native nano-fibrous structure in contrast to nanocellulose, for which further nanofibrillation is required. Nanopapers can be manufactured from fungal chitin nanofibrils (FChNFs). FChNF nanopapers are potentially applicable in packaging films, composites, or membranes for water treatment due to their distinct surface properties inherited from the composition of chitin and glucan. Here, chitin-glucan nanofibrils were extracted from common mushroom (Agaricus bisporus) cell walls utilizing a mild isolation procedure to preserve the native quality of the chitin-glucan complex. These extracts were readily disintegrated into nanofibre dimensions by a low-energy mechanical blending, thus making the extract dispersion directly suitable for nanopaper preparation using a simple vacuum filtration process. Chitin-glucan nanopaper morphology, mechanical, chemical, and surface properties were studied and compared to chitin nanopapers of crustacean (Cancer pagurus) origin. It was found that fungal extract nanopapers had distinct physico-chemical surface properties, being more hydrophobic than crustacean chitin.
Mautner A, Nawawi WMFW, Lee K-Y, et al., 2020, High porosity cellulose nanopapers as reinforcement in multi-layer epoxy laminates, Composites Part A: Applied Science and Manufacturing, Vol: 131, Pages: 1-9, ISSN: 1359-835X
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-resin. High-porosity nanopapers facilitate better resin impregnation, truly utilizing the properties of single cellulose nanofibres instead of the nanofibre network. We report the use of high-porosity (74%) but low strength and modulus bacterial cellulose (BC) nanopapers, prepared from BC-in-ethanol dispersion, as reinforcement for epoxy-resin. High-porosity nanopapers allowed for full impregnation of the BC-nanopapers with epoxy-resin. The resulting BC-reinforced epoxy-laminates possessed high tensile modulus (9 GPa) and strength (100 MPa) at a BC loading of 30 vol-%, resulting from very low void-fraction (3 vol-%) of these papregs compared to conventional nanopaper-laminates (10+ vol.-%). Better resin impregnation of less dense nanocellulose networks allowed for maximum utilization of stiffness/strength of cellulose nanofibrils.
Jones M, Mautner A, Luenco S, et al., 2020, Engineered mycelium composite construction materials from fungal biorefineries: A critical review, MATERIALS & DESIGN, Vol: 187, ISSN: 0264-1275
Nawawi WMFBW, Jones M, Murphy RJ, et al., 2020, Nanomaterials derived from fungal sources-is It the new hype?, Biomacromolecules, Vol: 21, Pages: 30-55, ISSN: 1525-7797
Greener alternatives to synthetic polymers are constantly being investigated and sought after. Chitin is a natural polysaccharide that gives structural support to crustacean shells, insect exoskeletons, and fungal cell walls. Like cellulose, chitin resides in nanosized structural elements that can be isolated as nanofibers and nanocrystals by various top-down approaches, targeted at disintegrating the native construct. Chitin has, however, been largely overshadowed by cellulose when discussing the materials aspects of the nanosized components. This Perspective presents a thorough overview of chitin-related materials research with an analytical focus on nanocomposites and nanopapers. The red line running through the text emphasizes the use of fungal chitin that represents several advantages over the more popular crustacean sources, particularly in terms of nanofiber isolation from the native matrix. In addition, many β-glucans are preserved in chitin upon its isolation from the fungal matrix, enabling new horizons for various engineering solutions.
Jiang Q, Morand A, Menner A, et al., 2020, Emulsion templated resilient macroporous elastomers, POLYMER, Vol: 186, ISSN: 0032-3861
Robinson P, Zhang B, Bismarck A, et al., 2020, Development of an interleaved composite with a two-stage shape memory capability for deployable structure applications
A carbon fibre epoxy composite laminate containing thermoplastic interleaves has been shown to provide an easy route for the manufacture of an expanded composite mesh. A two-stage shape memory composite using two different interleaf materials has been developed and this has been used to create a mesh that can deploy from the flat state into an expanded state. Creep of one of the interleaf materials, during flattening and deployment, limited the extent of the deployment but a better choice of interleaf materials should overcome this shortcoming.
Rusakov D, Khakhulin P, Menner A, et al., 2020, Development of porous polymer materials based on dicyclopentadiene from high internal phase emulsion with surface modification
Emulsion templated high porocity polydicyclopentadiene (PDCDP) has been prepared by Ring Opening Metathesis Polymerisation (ROMP). Unsaturated double bonds in the macroporous PDCDP surface were modified by Heck reaction for amination and radical addition reaction to introduce trifluoromethyl groups. As consequence of the modification, the surface properties of porous PDCD dramatically changed as evidenced by vastly different wetting behavior of the porous polymers.
Fortea-Verdejo M, Ho A, Qian H, et al., 2020, Paper-based composites for packaging applications
There is a waste problem with plastics used for packaging and used biopolymers, i.e. PLA, could be the solution. Unfortunately, they have some drawbacks compared to commonly used plastics for packaging applications. Could the performance of bioplastics be improved by implementing an interconnected network as reinforcement? Hybrid papers from nanocellulose and pulp fibres derived from bagasse were used in this work to produce hierarchical PLA composites suitable for packaging applications, due to their high tensile strength and low oxygen transmission rate, derived from the network structure fromed by the cellulosic fibres. The composites were manufactured by compression moulding of the PLA film in between hybrid papers. This could offer a biobased and biodegradable solution for the waste problem we are currently facing.
Mayer F, Mautner A, Lee KY, et al., 2020, Better through synergy: Hybridised cellulose for nanopaper composites
This study is about the manufacture of hybridised cellulose nanopapers made from bacterial cellulose (BC) processed in various ways. BC was extracted from Nata de Coco, a food product popular in southeast Asia, and either used as it was, refined by grinding in a disc mill (r-BC) or after TEMPO-mediated oxidation (T-BC). These three grades of BC were then combined in binary or ternary blends and processed similar to traditional paper making to manufacture nanopapers. A paper comprised of nanocellulose produced by TEMPO-mediated oxidation of birch Kraft-pulp (TEMPO-CNF) was used as reference. The network structure of the papers was investigated by scanning electron microscopy and tensile tests were performed to analyse the mechanical properties. Hybridised T-BC and BC nanopapers were found to yield higher tensile properties than nanopapers made from the individual constituents. However, the effect of hybridisation was lower compared to blends of BC and TEMPO-CNF. The results suggest that in order to achieve optimal nanopapers properties it is advantageous to combine nanocelluloses from different sources as this enables achieving a wider variety of nanofibril diameters which is favourable for hybridisation.
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