Nick Tucker | Plant and Food Research (original) (raw)
Papers by Nick Tucker
The traditional methods of combining fibrous reinforcement with resin matrix have been dictated b... more The traditional methods of combining fibrous reinforcement with resin matrix have been dictated by the properties of the matrix. If a thermoset matrix is used the low viscosity of the unreacted system can be exploited to either mix in quantities of short fibre reinforcement, as with bulk moulding compound, or to infiltrate the resin through reinforcement as with resin transfer moulding, however it is necessary to ensure that the moulded article is formed into its final shape before the resin cures. If a thermoplastic resin is selected then the high viscosity of material means that the blending of reinforcement and fibre must usually be performed under condition of high temperature and shear, as for example by compounding extruder or calendaring. This paper describes a method of exploiting the soluble nature of certain biodegradable polymers to produce an injection mouldable short fibre reinforced material without a mechanical compounding stage. This method combines the low viscosity...
This paper describes the behaviour and design of the spinning tip, the effect of solution conduct... more This paper describes the behaviour and design of the spinning tip, the effect of solution conductivity and the effect of substrate choice (Stanger et al 2009) on the development of a laboratory scale electrospinning machine from first principles through to commercial production. The need for such a machine grew out of a particular interest in the potential of electrospun biological
Journal of Materials Science, 2012
This study investigates the magnitude of movement of the area of deposition of electrospun fibres... more This study investigates the magnitude of movement of the area of deposition of electrospun fibres in response to an applied auxiliary electric field. The auxiliary field is generated by two pairs of rod electrodes positioned adjacent and parallel to the line of flight of the spun fibre. The changes in shape of the deposition area and the degree of movement of the deposition area are quantified by optical scanning and image analysis. A linear response was observed between the magnitude of movement of the deposition area and voltage difference between the auxiliary and deposition electrodes. A squeezing effect which changed the aspect ratio of the deposition area was also observed to result from the application of symmetric electrical fields. Statistical analysis showed that the deflection and squeezing responses can be thought of as independent control actions. The results from this experiment suggest this particular application of superposition of electric fields could be used as to control the flight path of an electrospun fibre. metallic plates were used to manipulate the electric fields for producing circumferential or axial oriented fibre.
Fibres with a diameter in the nanometer range were electrospun from aqueous poly(vinyl alcohol) (... more Fibres with a diameter in the nanometer range were electrospun from aqueous poly(vinyl alcohol) (PVOH). In order to improve the mass deposition rate and decrease the final fibre diameter salts (NaCl, LiCl, LiBr and LiF) were added to the solution. The aim was to increase the charge density and hence increase the electrostatic forces on the fluid. It was found that with increasing salt concentration the charge density did increase. However the mass deposition rate was found to decrease and the final fibre diameter was found to increase. The decrease in mass deposition rate is explained by considering the concept of a virtual orifice. The increase in the final fibre diameter is explained by considering the charge distribution in the jet when it behaves like a conductor compared to when it behaves like an insulator. Both mechanisms result from the increase in conductivity of the PVOH solution without significantly modifying other solution properties when salt is added.
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Polymer Testing, 2005
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Journal of Applied Polymer Science, 2009
Poly(vinyl alcohol) (PVOH) was electrospun using different methods to charge the polymer solution... more Poly(vinyl alcohol) (PVOH) was electrospun using different methods to charge the polymer solution. A positive high voltage relative to the collecting electrode significantly increased the fiber deposition rate. Electron microscopy showed that approximately half of the increase in fiber mass was due to thicker fibers being deposited. The current flowing from the grounded electrode was measured to determine the charge carried on the PVOH jet. This showed that for a positive voltage charging condition there is a much larger current and hence more charge carriers generated in the PVOH solution. As a result, more mass is ejected from the Taylor cone, implying that a positive voltage also produces longer fiber for a given time period. We also tested whether different substrate materials caused any variation when the charging conditions were changed. Statistically significant variation between substrates was only found when the substrate was an insulator and was expected to support a high-deposition rate. This confirms the view that the PVOH fiber arrives at the collecting electrode carrying a charge that must be neutralized, otherwise a repulsive charge will form where the fiber is deposited and some fiber will be lost to any alternative earth. In electrospraying, charge carriers are generated using associated redox reactions. Thus, for electrospinning a lack of symmetry in these reactions may result in the generation of different quantities of charge carriers in the PVOH solution and changes in the mass deposition rate of electrospun fiber. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Industrial Crops and Products, 2005
This paper examines the possibilities of using an established energy crop; Miscanthus giganteus a... more This paper examines the possibilities of using an established energy crop; Miscanthus giganteus as a filler/reinforcement in injection mouldable thermoplastic composites utilising a starch-based biopolymer; Novamont Mater-Bi as the matrix. A design of experiments methodology was used to reveal how varying the processing parameters and material formulation affected the impact performance of the biocomposite. The addition of Miscanthus fibres to the polymer results in composites with higher impact absorbance and loading than those of standard Mater-Bi.
Polymer Testing, 2003
Biodegradable composite ('biocomposite') test plaques consisting of Miscanthus fibres in a Novamo... more Biodegradable composite ('biocomposite') test plaques consisting of Miscanthus fibres in a Novamont Mater-Bi matrix were produced and tested in the laboratory. Plaques were also produced and tested that consisted of 100% Mater-Bi to provide a benchmark as to how the addition of Miscanthus fibres affect the impact performance of the biodegradable polymer ('biopolymer'). A design of experiments methodology was employed to impart data as to how processing parameters and material formulation affect the impact performance of the biocomposite. The factors that were varied during the course of the experiment were injection moulding machine screw speed, fibre volume, particle size and injection moulding machine barrel temperature. In comparison with pure Mater-Bi , the Miscanthus filled polymer exhibited up to 30% higher impact loads. The factors that affect the performance were discovered to be the temperature of the barrel and the rotational speed of the screw.
Industrial Crops and Products, 2005
This paper examines the possibilities of using an established energy crop; Miscanthus giganteus a... more This paper examines the possibilities of using an established energy crop; Miscanthus giganteus as a filler/reinforcement in injection mouldable thermoplastic composites utilising a starch-based biopolymer; Novamont Mater-Bi as the matrix. A design of experiments methodology was used to reveal how varying the processing parameters and material formulation affected the impact performance of the biocomposite. The addition of Miscanthus fibres to the polymer results in composites with higher impact absorbance and loading than those of standard Mater-Bi.
Industrial Crops and Products, 2007
Natural fibre-reinforced polymer composites have found increased favour of late, particularly wit... more Natural fibre-reinforced polymer composites have found increased favour of late, particularly within the automotive industry where Kenaf is often used alongside flax, hemp and jute as a reinforcement for car panels door trims and parcel shelves, for example. By developing viable composites from alternative materials grown in the UK (i.e. Miscanthus), it is hoped to increase financial opportunities for farmers
Solid State Phenomena, 2009
A detailed understanding of charge density and its origins during the electrospinning process is ... more A detailed understanding of charge density and its origins during the electrospinning process is desirable for developing new electrospinnable polymer-solvent systems and ensuring mathematical models of the process are accurate. In this work, two different approaches were taken to alter the charge density in order to measure its effect on the Taylor cone, mass deposition rate and initial jet diameter. It was found that an increase in charge density results in a decrease in the mass deposition rate and initial jet diameter. A theory is proposed for this behaviour in that an increase in charge density leads to the tip of the Taylor cone forming a smaller radius of curvature resulting in the concentration of electric stresses at the tip. This leads to the electrostatic forces drawing the initial jet from a smaller effective area or "virtual orifice".
The traditional methods of combining fibrous reinforcement with resin matrix have been dictated b... more The traditional methods of combining fibrous reinforcement with resin matrix have been dictated by the properties of the matrix. If a thermoset matrix is used the low viscosity of the unreacted system can be exploited to either mix in quantities of short fibre reinforcement, as with bulk moulding compound, or to infiltrate the resin through reinforcement as with resin transfer moulding, however it is necessary to ensure that the moulded article is formed into its final shape before the resin cures. If a thermoplastic resin is selected then the high viscosity of material means that the blending of reinforcement and fibre must usually be performed under condition of high temperature and shear, as for example by compounding extruder or calendaring. This paper describes a method of exploiting the soluble nature of certain biodegradable polymers to produce an injection mouldable short fibre reinforced material without a mechanical compounding stage. This method combines the low viscosity...
This paper describes the behaviour and design of the spinning tip, the effect of solution conduct... more This paper describes the behaviour and design of the spinning tip, the effect of solution conductivity and the effect of substrate choice (Stanger et al 2009) on the development of a laboratory scale electrospinning machine from first principles through to commercial production. The need for such a machine grew out of a particular interest in the potential of electrospun biological
Journal of Materials Science, 2012
This study investigates the magnitude of movement of the area of deposition of electrospun fibres... more This study investigates the magnitude of movement of the area of deposition of electrospun fibres in response to an applied auxiliary electric field. The auxiliary field is generated by two pairs of rod electrodes positioned adjacent and parallel to the line of flight of the spun fibre. The changes in shape of the deposition area and the degree of movement of the deposition area are quantified by optical scanning and image analysis. A linear response was observed between the magnitude of movement of the deposition area and voltage difference between the auxiliary and deposition electrodes. A squeezing effect which changed the aspect ratio of the deposition area was also observed to result from the application of symmetric electrical fields. Statistical analysis showed that the deflection and squeezing responses can be thought of as independent control actions. The results from this experiment suggest this particular application of superposition of electric fields could be used as to control the flight path of an electrospun fibre. metallic plates were used to manipulate the electric fields for producing circumferential or axial oriented fibre.
Fibres with a diameter in the nanometer range were electrospun from aqueous poly(vinyl alcohol) (... more Fibres with a diameter in the nanometer range were electrospun from aqueous poly(vinyl alcohol) (PVOH). In order to improve the mass deposition rate and decrease the final fibre diameter salts (NaCl, LiCl, LiBr and LiF) were added to the solution. The aim was to increase the charge density and hence increase the electrostatic forces on the fluid. It was found that with increasing salt concentration the charge density did increase. However the mass deposition rate was found to decrease and the final fibre diameter was found to increase. The decrease in mass deposition rate is explained by considering the concept of a virtual orifice. The increase in the final fibre diameter is explained by considering the charge distribution in the jet when it behaves like a conductor compared to when it behaves like an insulator. Both mechanisms result from the increase in conductivity of the PVOH solution without significantly modifying other solution properties when salt is added.
[
Polymer Testing, 2005
RefDoc Bienvenue - Welcome. Refdoc est un service / is powered by. ...
Journal of Applied Polymer Science, 2009
Poly(vinyl alcohol) (PVOH) was electrospun using different methods to charge the polymer solution... more Poly(vinyl alcohol) (PVOH) was electrospun using different methods to charge the polymer solution. A positive high voltage relative to the collecting electrode significantly increased the fiber deposition rate. Electron microscopy showed that approximately half of the increase in fiber mass was due to thicker fibers being deposited. The current flowing from the grounded electrode was measured to determine the charge carried on the PVOH jet. This showed that for a positive voltage charging condition there is a much larger current and hence more charge carriers generated in the PVOH solution. As a result, more mass is ejected from the Taylor cone, implying that a positive voltage also produces longer fiber for a given time period. We also tested whether different substrate materials caused any variation when the charging conditions were changed. Statistically significant variation between substrates was only found when the substrate was an insulator and was expected to support a high-deposition rate. This confirms the view that the PVOH fiber arrives at the collecting electrode carrying a charge that must be neutralized, otherwise a repulsive charge will form where the fiber is deposited and some fiber will be lost to any alternative earth. In electrospraying, charge carriers are generated using associated redox reactions. Thus, for electrospinning a lack of symmetry in these reactions may result in the generation of different quantities of charge carriers in the PVOH solution and changes in the mass deposition rate of electrospun fiber. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Industrial Crops and Products, 2005
This paper examines the possibilities of using an established energy crop; Miscanthus giganteus a... more This paper examines the possibilities of using an established energy crop; Miscanthus giganteus as a filler/reinforcement in injection mouldable thermoplastic composites utilising a starch-based biopolymer; Novamont Mater-Bi as the matrix. A design of experiments methodology was used to reveal how varying the processing parameters and material formulation affected the impact performance of the biocomposite. The addition of Miscanthus fibres to the polymer results in composites with higher impact absorbance and loading than those of standard Mater-Bi.
Polymer Testing, 2003
Biodegradable composite ('biocomposite') test plaques consisting of Miscanthus fibres in a Novamo... more Biodegradable composite ('biocomposite') test plaques consisting of Miscanthus fibres in a Novamont Mater-Bi matrix were produced and tested in the laboratory. Plaques were also produced and tested that consisted of 100% Mater-Bi to provide a benchmark as to how the addition of Miscanthus fibres affect the impact performance of the biodegradable polymer ('biopolymer'). A design of experiments methodology was employed to impart data as to how processing parameters and material formulation affect the impact performance of the biocomposite. The factors that were varied during the course of the experiment were injection moulding machine screw speed, fibre volume, particle size and injection moulding machine barrel temperature. In comparison with pure Mater-Bi , the Miscanthus filled polymer exhibited up to 30% higher impact loads. The factors that affect the performance were discovered to be the temperature of the barrel and the rotational speed of the screw.
Industrial Crops and Products, 2005
This paper examines the possibilities of using an established energy crop; Miscanthus giganteus a... more This paper examines the possibilities of using an established energy crop; Miscanthus giganteus as a filler/reinforcement in injection mouldable thermoplastic composites utilising a starch-based biopolymer; Novamont Mater-Bi as the matrix. A design of experiments methodology was used to reveal how varying the processing parameters and material formulation affected the impact performance of the biocomposite. The addition of Miscanthus fibres to the polymer results in composites with higher impact absorbance and loading than those of standard Mater-Bi.
Industrial Crops and Products, 2007
Natural fibre-reinforced polymer composites have found increased favour of late, particularly wit... more Natural fibre-reinforced polymer composites have found increased favour of late, particularly within the automotive industry where Kenaf is often used alongside flax, hemp and jute as a reinforcement for car panels door trims and parcel shelves, for example. By developing viable composites from alternative materials grown in the UK (i.e. Miscanthus), it is hoped to increase financial opportunities for farmers
Solid State Phenomena, 2009
A detailed understanding of charge density and its origins during the electrospinning process is ... more A detailed understanding of charge density and its origins during the electrospinning process is desirable for developing new electrospinnable polymer-solvent systems and ensuring mathematical models of the process are accurate. In this work, two different approaches were taken to alter the charge density in order to measure its effect on the Taylor cone, mass deposition rate and initial jet diameter. It was found that an increase in charge density results in a decrease in the mass deposition rate and initial jet diameter. A theory is proposed for this behaviour in that an increase in charge density leads to the tip of the Taylor cone forming a smaller radius of curvature resulting in the concentration of electric stresses at the tip. This leads to the electrostatic forces drawing the initial jet from a smaller effective area or "virtual orifice".