Improving gelling properties of myofibrillar proteins incorporating with cellulose micro/nanofibres

The effects of cellulose microfibres (CMFs, Average size: 100 ± 5 μm) and cellulose nanofibres (CNFs, Average size: 60 ± 3 nm) on the properties of myofibrillar protein (MP) gels from duck breast meat were studied. The results demonstrated that CMFs and CNFs were mostly connected to MP by non-covalent bonds, the diffusion and cross-linking of MP molecules was promoted, and a denser and more complete gel network was formed. With the increases of CMFs and CNFs concentration (0–10%), the hardness was increased by 13.15% and 19.78% for CMFs10% and CNFs10% gels, respectively, and the elasticity was increased by 40% and 80%, respectively. At the same concentration (0–10%), the increase in gel hardness, viscoelasticity and immobilised water content was greater in the CNFs-MP group than in the CMFs-MP group. The CNFs-MP group had a tighter gel network, and CNFs had a better potential to improve the gelation performance of MP.     

Toughened electrospun nanofibers from crosslinked elastomer‐thermoplastic blends

A crosslink‐able elastomeric polyester urethane (PEU) was blended with a thermoplastic, polyacrylonitrile (PAN), and electrospun into nanofibers. The effects of the PEU/PAN ratio and the crosslinking reaction on the morphology and the tensile properties of the as‐spun fiber mats were investigated. With the same overall polymer concentration (9 wt %), the nanofiber containing higher composition of PEU shows a slight decrease in the average fiber diameter, but the tensile strength, the elongation at break and tensile modulus of the nanofiber mats are all improved. These tensile properties are further enhanced by slight crosslinking of the PEU component within the nanofibers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis and characterisation of fluorescent pyrene‐end‐capped polylactide fibres

Fluorescent markers are critical for tracking the position and movement of molecules both in vivo and in vitro. Conventionally, synthetic dyes are non‐covalently added to polymers for fluorescent tracking, but often diffuse away. Here we demonstrate, for the first time, a facile method for the synthesis of fluorescent poly(lactic acid) nano‐/microfibres for biomedical applications using solution spin blowing. Pyrene‐end‐capped poly(l ‐lactide) (PLLA) derivatives were synthesised using the ring‐opening polymerisation of l ‐lactide and they were characterised using spectroscopic and thermal analyses. Submicrometre‐sized fluorescent fibres were produced from these PLLA derivatives using solution blow spinning techniques generating polymer blends and core–shell fibres. Such system could be further exploited to incorporate electrically conductive carbon allotropes via the pyrene aromaticity, producing fluorescent and electrically active fibres for in vitro monitoring and electrical stimulation. © 2018 Society of Chemical Industry     

A systematic investigation into a novel method for preparing carbon fibre–carbon nanotube hybrid structures

By electrospraying solvent dispersed carbon nanotubes (CNTs) with a binder onto carbon fibre (CF), hybrid structures, with an end aim to improve interfacial bonding in composites, were formed. The electrospray parameters controlling the modification of the CNT morphologies were studied. High-speed camera observations found applied voltage was critical for determining spray mode development. Electric field simulations revealed a concentrated electric field region around each fibre. Both voltage and distance played an important role in determining the CNT morphology by mediating anchoring strength and electric field force. The forming mechanism investigation of different surface morphologies suggested that binder with appropriate wetness gives freedom to the CNTs, allowing them to orientate radially from the CF surface. Linear density (LD) measurements and thermogravimetric analysis revealed that a 10 min coating increased the LD of a single CF filament by up to 31.7% while a 1 h treatment increased fibre bundle mass by 1%.     

Water soluble polymeric nanofibres for rapid flocculation and enhanced dewatering of mature fine tailings

Water-soluble polymer flocculants have been used to efficiently release entrapped water in oil sands tailings by bridging fine particles to create large heavier flocs which can then settle faster and release water more efficiently. Due to their initial interaction with the fine particles suspended in tailings, polymer nanofibres may perform better than their parent polymers because of the entire surface of the nanofibres being fully accessible to the fine particles. In this work, commercially available poly(acrylamide-co-diallyl dimethylammonium chloride) was chosen as a basis for this study. Initial settling rate, supernatant turbidity, water recovery, capillary suction time, and solids content were measured to determine the effect of polymer nanofibres on solid-liquid separation. The solid forms of the polymer (either as nanofibre or powder) perform better than the polymer solution in each test, with optimum dosages of 5 wt% mature fine tailings (MFT) loading. Nanofibres could achieve settling rates of 60 m/h, while the other forms were only able to achieve 42 m/h. Additionally, the turbidity of the supernatant obtained after flocculation with nanofibres was 15 nephelometric turbidity units (NTU), while the polymer solution and powder produced turbidites of 162 NTU and 70 NTU, respectively. In addition, polymer nanofibres and powders generated larger flocs compared to the polymer solution, which produced small, homogenized flocs.     

Advances in electrospinning: The production and application of nanofibres and nanofibrous structures

The use of electrospun nanofibres in applications such as medical products, fuel cells, photocatalysis, filtration, sensors and actuators is reviewed. Yarn production is classified into two types, namely hollow and core-shell structures; the methods used for producing the two structures for different polymers are discussed. Explanations are given for the various arrangements for producing nanofibre yarns and bundles in non-twisted or twisted forms to suit their end use. Natural and synthetic polymer products for biomedical uses and their applications in the form of polymer nanofibres are reviewed and polymeric optical fibres for use in photonic devices and optical circuits are evaluated. The production and development of nanofibrous filtration devices is explored with specific reference to water treatment and the control of air pollution. Particular attention is then given to the evaluation of different electrospinning methods for PVDF (polyvinylidene fluoride), a piezoelectric polymer widely used in sensor applications in terms of their ability to harvest more energy after agitation of the sensor and the effects of different additives on the piezoelectric properties of PVDF. Priorities for further research are then outlined.     

Identification of valence shifts in Au during the water-gas shift reaction

In situ X-ray absorption spectroscopy (XAS) has been performed to investigate the active site on Au-based catalysts in the water-gas shift (WGS) reaction. The surface area and hence the WGS activity is higher for AuTiO₂ catalysts supported on carbon nanofibres (CNF) than TiO₂. The WGS reaction rate depends on the Au coordination number with an apparent maximum close to eight which corresponds to a particle size of approximately 2.5–3.0 nm. A likely cause for the changes in the electronic structure of Au is the adsorption of CO on the surface, which also creates a small positive charge in the Au atoms. The catalytic activity significantly improves when titania is present compared to Au deposited directly on CNF.     

Catalytic decomposition of methane for the simultaneous co-production of CO2-free hydrogen and carbon nanofibre based polymers

Through the catalytic decomposition of methane (CDM) it is possible to obtain in a single step both CO₂-free hydrogen and carbon nanostructures with a wide range of applications such as nanocomposite reinforcements. In this work, a Ni-based catalyst has been used to carry out the catalytic decomposition, obtaining an hydrogen concentration up to 47% (vol.) in the flue gas and carbon nanofibres (CNF). These structures have been inserted into two epoxy resins with different viscosity in order to study the influence of the CNF load in the electrical resistivity of the new materials prepared. As a result, the resistivity of these materials decreases up to 10⁶ Ω cm, values which avoid the electrostatic discharge and allow the electrostatic painting.     

碳纳米纤维吸附储氢性能评价

利用N2(T=77K)、H2(T=298K)在三种碳纳米纤维材料中的吸附等温线，对这三种材料的吸附储氢性能进行了评价。以N2在77K下的吸附等温线为基础，分别用BET方法和BJH方法计算了这三种材料的比表面积和孔径分布，讨论了比表面积、孔径分布和吸附性能之间的关系。计算和实验结果表明：这三种材料均只含有少量的微孔，吸附性能较差。在三种后处理方法中，以水蒸气氧化法的效果最好，所得材料比表面积最大，微孔容积所占比例也最大，相应的吸附性能也最好。     

Use of Water as a Solvent in Directing Hydrogenation Reactions of Aromatic Acids over Pd/carbon Nanofibre Catalysts

By conducting the catalytic hydrogenation over water miscible Pd/carbon nanofibre catalysts, selective ring hydrogenation of aromatic acids can be performed in aqueous solution without the need to provide protection for the external acid function.