Papers by Hisham M. Abourayana
Journal of Applied Polymer Science, 2020
This work studied the effects of adding short basalt fibres (BFs) and multi-walled carbon nanotub... more This work studied the effects of adding short basalt fibres (BFs) and multi-walled carbon nanotubes (MWCNTs), both separately and in combination, on the mechanical properties, fracture toughness and electrical conductivity of an epoxy polymer. The surfaces of the short BFs were either treated by silane coupling agent or further functionalised by atmospheric plasma to enhance the adhesion between the BFs and the epoxy. The results of a single fibre fragmentation test demonstrated a significantly improved BF/epoxy adhesion upon applying the plasma treatment to the BFs. This resulted in better mechanical properties and fracture toughness of the composites containing the plasma-activated BFs. The improved BF/epoxy adhesion also affected the hybrid toughening performance of the BFs and MWCNTs. In particular, synergistic toughening effects were observed when the plasma-activated BFs/MWCNTs hybrid modifiers were used, while only additive toughening effects occurred for the silane-sized BFs/MWCNTs hybrid modifiers. This work demonstrated a potential to develop strong, tough and electrically conductive epoxy composites by adding hybrid BF/MWCNT modifiers.
Plasma Processes and Polymers, Oct 16, 2017
World Academy of Science, Engineering and Technology, International Journal of Chemical, Molecular, Nuclear, Materials and Metallurgical Engineering, 2011
Polymer-like organic thin films were deposited on both aluminum alloy type 6061 and glass substra... more Polymer-like organic thin films were deposited on both aluminum alloy type 6061 and glass substrates at room temperature by Plasma Enhanced Chemical Vapor Deposition (PECVD) methodusing benzene and hexamethyldisiloxane (HMDSO) as precursor materials. The surface and physical properties of plasma-polymerized organic thin films were investigated at different r.f. powers. The effects of benzene/argon ratio on the properties of plasma polymerized benzene films were also investigated. It is found that using benzene alone results in a non-coherent and non-adherent powdery deposited material. The chemical structure and surface properties of the asgrown plasma polymerized thin films were analyzed on glass substrates with FTIR and contact angle measurements. FTIR spectra of benzene deposited film indicated that the benzene rings are preserved when increasing benzene ratio and/or decreasing r.f. powers. FTIR spectra of HMDSO deposited films indicated an increase of the hydrogen concentration ...
Organic polymer thin films have been deposited on glass and aluminum alloy type 6061 substrates a... more Organic polymer thin films have been deposited on glass and aluminum alloy type 6061 substrates at room temperature and different radio frequency (r.f.) powers by plasma enhanced chemical vapor deposition (PECVD) method, using hexamethyldisiloxane (HMDSO) as organic precursor. Surface properties were characterized by scanning electron microscopy (SEM) and contact angle measurements. The SEM images indicate that the surface roughness decrease with increasing r.f. power, and the results of contact angle measurements indicated that the films deposited at the r.f. power 50 and 100 watt is hydrophilic while the one prepared at 150 watt is slightly hydrophobic ( > 90o). On the other hand, chemical properties were characterized by means of fourier transformed infrared spectroscopy (FTIR). The results indicated that, with the increase of r.f. power, the concentration of hydrogen in the film increases, while the concentration of oxygen decreases. The corrosion protective abilities of film...
This study reports on a comparison between two types of atmospheric plasma systems, a pulsed flui... more This study reports on a comparison between two types of atmospheric plasma systems, a pulsed fluidized bed and a barrel reactor, for the plasma activation of silicone particles. Both helium and helium /oxygen gas mixtures were used to generate the plasmas in the two reactors. Both reactors are cylindrical in shape with internal dimensions of 100 mm in length and diameters of 30 mm. The two reactors were used to treat 0.5 g of silicone polymer particles. The effects of plasma treatment time, operating voltage and gas flow rate, on changes in the water contact angle of the treated polymer were investigated. Optical Emission Spectroscopy (OES) facilitated the monitoring of reactive plasma species during treatment. Subsequent to their treatment, the polymer particles were analysed using X-ray Photoelectron Spectroscopy (XPS). As expected this analysis demonstrated an increase in oxygen content on the polymer surface after plasma activation. For a helium only plasma treatment, the water ...
This study reports on the performance of a scalable barrel atmospheric plasma system for the trea... more This study reports on the performance of a scalable barrel atmospheric plasma system for the treatment of polymer particles. A novel feature of the barrel system design is the use of a biased electrode, which also acts as the roller for the glass barrel. The plasma is generated using either helium or helium/oxygen gas mixtures. The reactor was used to activate 20 g batches of silicone, polypropylene (PP), acrylonitrile butadiene styrene (ABS) and polyethylene terephthalate (PET) particles, each with diameters in the range 3 to 5 mm. The effect of plasma treatment time and gas flow rate on the water contact angle of the treated polymer particles was examined. The polymer water contact angles decreased from up to 140° to 2 and N 2 + were monitored and correlated with their spatial distribution within the plasma chamber. Electrical characterisation studies demonstrated an increase in plasma power with increasing input voltage and helium flow rate. The heating effect of the plasma was m...
This study reports the development and performance of a pilot-scale barrel atmospheric plasma rea... more This study reports the development and performance of a pilot-scale barrel atmospheric plasma reactor for the atmospheric plasma activation treatment of polymer particles. The polymer particles treated included acrylonitrile butadiene styrene (ABS) and polypropylene (PP). These particles had diameters in the range of 3–5 mm. The initial studies were carried out using a laboratory-scale barrel reactor designed to treat polymer particle batch sizes of 20 g. A pilot-scale reactor that could treat 500 g particle batch sizes was then developed to facilitate pre-industrial-scale treatments. The effect of operating pulse density modulation (PDM) in the range 10%–100% and plasma treatment time on the level of activation of the treated polymers were then investigated. ABS revealed a larger decrease in water contact angle compared with PP after plasma treatment under the same conditions. The optimal treatment time of ABS (400 g of polymer particles) in the pilot-scale reactor was 15 min. The ...
This study reports on the use of a barrel atmospheric plasma source for the deposition of a fluor... more This study reports on the use of a barrel atmospheric plasma source for the deposition of a fluorocarbon coating onto the silicone polymer particles. The (Perfluoro-1-Decene) precursor was introduced into helium plasma and coatings deposited at flow rates in the range 5 to 9 μl/min. The retention of the chemical functionality of the precursor in the plasma polymerized coating was demonstrated using both XPS and FTIR analysis. This study thus demonstrates the success of the barrel reactor for the coating of polymer particles.
Polymers
Three-dimensional (3D) printing has been successfully applied for the fabrication of polymer comp... more Three-dimensional (3D) printing has been successfully applied for the fabrication of polymer components ranging from prototypes to final products. An issue, however, is that the resulting 3D printed parts exhibit inferior mechanical performance to parts fabricated using conventional polymer processing technologies, such as compression moulding. The addition of fibres and other materials into the polymer matrix to form a composite can yield a significant enhancement in the structural strength of printed polymer parts. This review focuses on the enhanced mechanical performance obtained through the printing of fibre-reinforced polymer composites, using the fused filament fabrication (FFF) 3D printing technique. The uses of both short and continuous fibre-reinforced polymer composites are reviewed. Finally, examples of some applications of FFF printed polymer composites using robotic processes are highlighted.
Surface Energy, Dec 16, 2015
This chapter details how plasma treatments can be used to tailor the wettability of polymers. A p... more This chapter details how plasma treatments can be used to tailor the wettability of polymers. A plasma is an excited gas, and exposure of a polymer to a plasma discharge generally results in an enhancement in surface energy and associated with this is an increase in wettability. The effect however can be short lived due to hydrophobic recovery. In this review the use of both low and atmospheric plasmas for the activation of polymers will be discussed, as will the use of these plasmas for the deposition of plasma polymerised coatings. The latter can be used to produce polymer surfaces with tailored functionalities, thus achieving stable water contact angles ranging from superhydrophilic to superhydrophobic, as required. This review briefly introduces plasmas and plasma processing and includes an overview of typical plasma treatment sources. This is followed by a review of the use of plasma discharges to treat polymers and in particular to enhance their surface energy, which is important for example in achieving enhanced adhesive bond strength. The final section of this chapter focuses on the deposition of plasma polymerised coatings and how these can be used to tailor both surface chemistry and morphology. Thus the wettability of polymer surfaces can be controlled.
Plasma Processes and Polymers
Nanotechnology and Precision Engineering
Plasma Chemistry and Plasma Processing
Surface and Coatings Technology
This study reports on the performance of a scalable barrel atmospheric plasma system for the trea... more This study reports on the performance of a scalable barrel atmospheric plasma system for the treatment of polymer particles. A novel feature of the barrel system design is the use of a biased electrode, which also acts as the roller for the glass barrel. The plasma is generated using either helium or helium/oxygen gas mixtures. The reactor was used to activate 20 g batches of silicone, polypropylene (PP), acrylonitrile butadiene styrene (ABS) and polyethylene terephthalate (PET) particles, each with diameters in the range 3 to 5 mm. The effect of plasma treatment time and gas flow rate on the water contact angle of the treated polymer particles was examined. The polymer water contact angles decreased from up to 140° to b10° after the barrel plasma treatment (polymer dependent). X-ray photoelectron spectroscopy (XPS) analysis is used to monitor the effect of the plasma treatment on both PET and silicone polymer particles. Optical emission spectroscopy (OES) was used as a diagnostic tool to monitor changes in atomic and molecular species intensity with experimental conditions. Emission lines of helium, oxygen and molecular bands of OH, N 2 and N 2 + were monitored and correlated with their spatial distribution within the plasma chamber. Electrical characterisation studies demonstrated an increase in plasma power with increasing input voltage and helium flow rate. The heating effect of the plasma was monitored using an infrared thermographic camera, the maximum barrel temperature after 30 min treatment found to be 29 °C. While the current barrel plasma system design can treat 20 g of polymer the system design has the potential to be readily scalable for the activation of larger batches of particles.
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Papers by Hisham M. Abourayana