Yazar "Shah, Tahir H." seçeneğine göre listele

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    Continuous production of piezoelectric PVDF fibre for e-textile applications
    (Iop Publishing Ltd, 2013) Hadimani, R. L.; Vatansever Bayramol, Derman; Sion, N.; Shah, Tahir H.; Qian, Limin; Shi, Shaoxin; Siores, Elias
    Polymers have been widely used as piezoelectric materials in the form of films and bulk materials but there are limited publications on piezoelectric fibre structures. In this paper the process of preparing piezoelectric polyvinylidene fluoride (PVDF) fibres from granules by continuous melt extrusion and in-line poling is reported for the first time. The poling of PVDF fibres was carried out at an extension ratio of 4:1, a temperature of 80 degrees C and a high voltage of the order of 13 000 V on a 0.5 mm diameter fibre in a melt extruder. The entire process of making PVDF fibres from granules and poling them to make piezoelectric fibres was carried out in a continuous process using a customized melt extruder. The prepared piezoelectric fibres were then tested using an impact test rig to show the generation of voltage upon application of an impact load. PVDF granules, unpoled fibres and poled fibres were examined by Fourier transform infrared spectroscopy (FTIR) which showed the presence of beta phase in the poled fibres. The ultimate tensile stress and strain, Young's modulus and microstructures of poled and unpoled fibres were investigated using a scanning electron microscope (SEM).
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    Effect of Addition of Multiwalled Carbon Nanotubes on the Piezoelectric Properties of Polypropylene Filaments
    (Amer Scientific Publishers, 2015) Vatansever Bayramol, Derman; Soin, Navneet; Hadimani, R. L.; Shah, Tahir H.; Siores, Elias
    The effect of addition of multiwalled carbon nanotubes (CNTs) on the piezoelectric properties of polypropylene (PP) monofilaments has been investigated. Various amounts of CNTs (0%, 0.01%, 0.1% and 1% weight ratios) were melt-blended with PP and the resulting nanocomposites were extruded in a continuous process with simultaneous on-line poling to produce monofilaments. Concurrent stretching at a draw ratio of 5:1 and polarisation at applied electric fields of 15 kV of PP/CNT filaments was observed to enhance the piezoelectric properties. The microstructure and crystallinity of the filaments was analysed using scanning electron microscopy (SEM), differential scanning calorimetric (DSC) and Fourier transform infrared spectroscopy (FTIR) techniques. Voltage generation by the CNT-modified PP filaments was determined by the application of predetermined load impact. The results show that the incorporation of CNTs in the PP fibre structure has a considerable impact on the enhancement of piezoelectric properties of the PP filament obtained that the peak voltage generation was almost four fold (from 0.76 V to 2.92 V) when 0.1 wt% of CNTs added into the polymer. This is owing to the fact that carbon nanotubes act as nucleating agent for enhancing the crystallisation during the melt extrusion process.
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    Energy Harvesting Smart Textiles
    (Springer International Publishing Ag, 2017) Vatansever Bayramol, Derman; Soin, Navneet; Shah, Tahir H.; Siores, Elias; Matsouka, Dimitroula; Vassiliadis, Savvas
    The ever-increasing population of the world is putting a significant demand on the need for multifunctional electronic devices and electricity to power them. This growing demand has led to an enhanced focus on the development of energy harvesting techniques based on renewable and ambient sources. Although materials having unique properties such as photovoltaic, piezoelectric and triboelectric have been known for a long time and have been utilized usually in the form of thin-film structures, their utilization in the form of textile structures for energy harvesting is a relatively new area of research. This chapter will focus on the recent advances in the area of photovoltaic, piezoelectric and triboelectric energy-generating textile structures and the fundamentals of these unique properties, production methods and textile-based energy storage. Finally, expected future trends in the fabrication and application of textile-based energy harvesting and storage will be discussed.
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    Novel 3-D spacer all fibre piezoelectric textiles for energy harvesting applications
    (Royal Soc Chemistry, 2014) Soin, Navneet; Shah, Tahir H.; Anand, Subhash C.; Geng, Junfeng; Pornwannachai, Wiwat; Mandal, Pranab; Siores, Elias; Bayramol, Derman Vatansever
    The piezoelectric effect in poly(vinylidene fluoride), PVDF, was discovered over four decades ago and since then, significant work has been carried out aiming at the production of high beta-phase fibres and their integration into fabric structures for energy harvesting. However, little work has been done in the area of production of true piezoelectric fabric structures based on flexible polymeric materials such as PVDF. In this work, we demonstrate 3D spacer technology based all-fibre piezoelectric fabrics as power generators and energy harvesters. The knitted single-structure piezoelectric generator consists of high beta-phase (similar to 80%) piezoelectric PVDF monofilaments as the spacer yarn interconnected between silver (Ag) coated polyamide multifilament yarn layers acting as the top and bottom electrodes. The novel and unique textile structure provides an output power density in the range of 1.10-5.10 mW cm(-2) at applied impact pressures in the range of 0.02-0.10 MPa, thus providing significantly higher power outputs and efficiencies over the existing 2D woven and nonwoven piezoelectric structures. The high energy efficiency, mechanical durability and comfort of the soft, flexible and all-fibre based power generator are highly attractive for a variety of potential applications such as wearable electronic systems and energy harvesters charged from the ambient environment or by human movement.
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    Preparation and characterization of PVDF-based nanocomposites
    (wiley, 2014) Vatansever Bayramol, Derman; Shah, Tahir H.; Soin, Navneet; Siores, Elias
    Energy is of great importance in our lives. There might have been a time when people lived without it, but now, after we all got used to having it, it is almost impossible to survive without the energy. However, the energy demand is increasing every day as the energy resources are decreasing so that we are likely to face an energy shortage. Researchers are well aware of the importance of energy; therefore, a significant number of studies are being carried out from different disciplines some of which involves using polymers and polymer blends. Poly(vinylidene fluoride) PVDF is the most widely used and studied polymer; yet, it is the first polymer discovered exhibiting piezoelectric property. This chapter reviews the synthesis and piezoelectric properties of PVDF; preparation and characterization of PVDF-based nanocomposites (polymer/polymer blends, polymer/nanoparticle blends, and ternary blends) and focuses specifically on preparation and characterization of PVDF-based nanocomposites for energy harvesting applications. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA.