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A multi walled carbon nanotube screen printed electrode modified with recombinant protein PbrR for detection of lead

- Molatji, Thulaganyo

An easy two-step microwave assisted synthesis of SnO2/CNT hybrids

- Motshekga, Sarah C, Pillai, Sreejarani K, Ray, Suprakas Sinha, Jalama, Kalala, Krause, Rui.W.M

Cyclodextrin polyurethane and carbon nanotube composites embedded in alginate beads for the removal of contaminants in water

- Ezuruike, Hilary Ihesinaulo

  • Authors: Ezuruike, Hilary Ihesinaulo
  • Date: 2012-05-02
  • Subjects: Cyclodextrins , Polyurethanes , Carbon nanotubes , Watter pollution treatment
  • Type: Thesis
  • Identifier: uj:2244 , http://hdl.handle.net/10210/4683
  • Description: M.Sc. , Water is often contaminated with organic and inorganic compounds by natural means and through human activities. Once contaminated, water of this nature has little or no use. However, water that is free from toxic chemicals is essential to both human health and the environment. Current water treatment techniques such as separation by membranes (reverse osmosis), adsorption (activated carbon) and ion exchange are not always very efficient at removing contaminants which may be present in parts per billion (ppb) levels. Techniques need to be developed that are reasonably inexpensive and easy to use, and yet effective at removing both organic and inorganic pollutants to acceptable levels. Adsorption is a technique that has the potential to meet these criteria. In our laboratories, insoluble beta cyclodextrin (β-CD) polymers have been used to remove pollutants from water at concentrations as low as ppb levels. However, they exhibited some disadvantages, such as poor structural integrity and difficulty in recovery. This project sought to deal with these limitations by incorporating functionalized multi-walled nanotubes (f-MWNTs) into the polymer, and then embedding polymer particles in an alginate matrix as small beads for ease of use. The polymer composites, 1% f-MWNTs with β-CD polyurethane, were synthesised and embedded in alginates to form alginate composite beads. Composite beads were tested against a model organic and heavy metal pollutants, namely p-nitrophenol and Pb2+, respectively. The composites were characterized using Fourier Transform Infra Red spectroscopy (FT-IR), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDXS), among other techniques. The absorption capacity of f-MWNTs, β-CD, and alginates combined proved to be effective and stable adsorbents. They showed an adsorption efficiency of at least 95% for p-nitrophenol at a concentration of 10 mg/L and 98% for Pb2+ at a concentration of 50 mg/L. vii The novel adsorbents show a good thermal stability and maintain their structural integrity after repeated (thirty times) use in recycling experiments. The recycled beads maintained a high average adsorption efficiency of 96%, indicating the potential cost benefit of these materials. As a comparison, the plain calcium alginate (CaAG) beads and plain β-CD polyurethane beads showed an average adsorption of 55% and 74%, respectively, but their structural integrity was significantly compromised during similar recycling. Brunauer Emmett Teller (BET) surface area analysis showed that incorporation of f-MWNTs (1% loading) increased the surface area of the composite beads, and adsorption isotherms showed a good fit with both Langmuir and Freundlich models. This project has demonstrated the use of f-MWNTs as copolymer which improves the structural stability of the polymers, and that the combination of these polymers and alginates provide a potentially useful material for water treatment applications.
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Early transition metal carbides-multiwalled carbon nanotubes-biopolymer nanocomposites in the application of hydrostatic pressure sensor

- Makhado, Bveledzani Pertunia

  • Authors: Makhado, Bveledzani Pertunia
  • Date: 2019
  • Subjects: Pressure transducers , Hydrostatic pressure , Transition metal carbides , Carbon nanotubes , Nanocomposites (Materials) , Biopolymers , Cellulose acetate
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/417534 , uj:35364
  • Description: Abstract: Pressure sensors are very significant and are used in various areas such as automobiles, aerospace, medical industry, energy storage, corrosion protection, electrochromic devices, electrochemical sensor. Most of the pressure sensors in the market are intended to operate either in the air, dry gases and water-based environments. Environmental interference hampered the pressure sensors effectiveness and life cycle. As a consequence, countless measurement and reading mistakes have been reported owing to interferences such as trapped air in a cylinder and elevated humidity, thus decreasing sensitivity and delaying response time. In this study, we determine the resistance sensitivity of a hydrostatic pressure sensor based on cellulose acetate (CA), alpinumisoflavone (BI), multiwalled carbon nanotubes (MWCNTs) and metal carbides (MC) nanocomposites deposited on integrated electrode. We intended to utilize a cost-effective, simple, fast deposition process and fabrication of thermoplastic polymers nanocomposites for pressure sensing device and to study electrical properties of pressure sensing and stability using LCR meter... , M.Sc. (Nanoscience)
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Effective photodynamic therapy for colon cancer cells using Chlorin e6 Coated Hyaluronic acid-based carbon nanotubes

- Sundaram, Prabhavathi, Abrahamse, Heidi

  • Authors: Sundaram, Prabhavathi , Abrahamse, Heidi
  • Date: 2020
  • Subjects: Ccolon cancer , Chlorin e6 , Carbon nanotubes
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/426594 , uj:36597 , Sundaram, P., Abrahamse, H.: Effective photodynamic therapy for colon cancer cells using Chlorin e6 Coated Hyaluronic acid-based carbon nanotubes. DOI:10.3390/ijms21134745
  • Description: Abstract: Colon cancer is the third major cancer contributor to mortality worldwide. Nanosized particles have attracted attention due to their possible contribution towards cancer treatment and diagnosis. Photodynamic therapy (PDT) is a cancer therapeutic modality that involves a light source, a photosensitizer and reactive oxygen species. Carbon nanotubes are fascinating nanocarriers for drug delivery, cancer diagnosis and numerous potential applications due to their unique physicochemical properties. In this study, single walled carbon nanotubes (SWCNTs) were coupled with hyaluronic acid (HA) and chlorin e6 (Ce6) coated on the walls of SWCNTs. The newly synthesized nanobiocomposite was characterized using ultraviolet-visible spectroscopy, Fourier transform electron microscopy (FTIR), X-ray diffraction analysis (XRD), particle size analysis and zeta potential. The loading efficiency of the SWCNTs-HA for Ce6 was calculated. The toxicity of the nanobiocomposite was tested on colon cancer cells using PDT at a fluence of 5 J/cm2 and 10 J/cm2 . After 24 h, cellular changes were observed via microscopy, LDH cytotoxicity assay and cell death induction using annexin propidium iodide. The results showed that the newly synthesized nanobiocomposite enhanced the ability of PDT to be a photosensitizer carrier and induced cell death in colon cancer cells.
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Effects of multi-walled carbon nanotubes on strength and interfacial transition zone of concrete

- Van Tonder, P., Mafokoane, T.T.

  • Authors: Van Tonder, P. , Mafokoane, T.T.
  • Date: 2014
  • Subjects: Carbon nanotubes , Concrete - Mixing , Materials - Testing
  • Type: Article
  • Identifier: uj:5057 , ISBN 9781614994657 , ISBN 9781614994664 , http://hdl.handle.net/10210/13619
  • Description: Multi-walled carbon nanotubes (MWCNTs) were used to try and eliminate the aggregate interfacial transition zone. Different concrete mixes were used in fixed proportions along with varying concentrations of CNTs. The CNTs were applied in different concentrations, namely, 0.05 wt%, 0.1 wt% and 0.2 wt%, per dry weight. CNTs were dispersed using sonication. Concrete specimens were tested for compressive, flexural and split-tensile strengths. For each test, thirteen mix designs were investigated which included untreated aggregates and CNTs, and treated aggregates and CNTs. The results were compared with the results of the control concrete. The results showed that the use of CNTs improves the compressive, flexural and split-tensile strengths. It was concluded that CNTs minimize the ITZ.
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Electrochemical studies and sensing of iodate, periodate and sulphite ions at carbon nanotubes/ Prussian blue films modified platinum electrode

- Adekunle, Abolanle S., Arotiba, Omotayo A., Mamba, Bhekie B.

Fabrication of hyperbranched polyethyleneimine membrane blended with multiwalled carbon-nanotubes for the removal of pb(ii) from water

- Masenye, Edward Rorisang

  • Authors: Masenye, Edward Rorisang
  • Date: 2019
  • Subjects: Nanoscience , Carbon nanotubes , Water - Purification - Lead removal , Lead abatement
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/401213 , uj:33520
  • Description: Abstract : Wastewater contamination with inorganic and organic compounds has become a major environmental problem. This is due to human activities such as urban developments, agricultural activities, and mining industries. Water pollution by heavy metals such as, Pb(II) in particular has unavoidable hazards to human health as it causes undesirable diseases, such as peripheral and central nervous system rupture. Currently there are water treatment technologies which are in use such as ion exchange, flocculation and coagulation, but these technologies are not efficient in removing Pb(II) to parts per billion (ppb) levels. There is a need to implement new techniques which are more efficient in removing Pb(II) to acceptable concentration levels. Membrane technology is a newly emerging water treatment method, because it has proved to remove trace metals at ppb levels. In this study a composite membrane was synthesized via interfacial polymerization with multiwalled carbonnanotubes (MWCNTs) as nano-fillers, hyperbranched polyethyleneimine (HPEI) as a dispersing agent and polysulfone (PSf) as a support. The fabricated membrane was characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), and contact angle. FTIR spectra confirmed that interfacial polymerization indeed occurred by the emergence of polyamide layer at the interface of the membrane. The appearance of v(NH-C=O), v(O=C-Cl) further confirmed that HPEI/MWCNTs reacted with TMC to form a thin film. Upon addition of the composite on the PSf support, an increase in hydrophilicity was observed. At 600 KPa the flux of the pristine PSf, HPEI/MWCNT/PSf-0.2% (M-1%), HPEI/MWCNT/PSf-0.5% (M-0.5%) and HPEI/MWCNT/PSf-1% (M-1%) was revealed to be 136.15 L/h.m2, 16.66 L/h.m2, 14.83 L/h.m2 and 13.03 L/h.m2 respectively. The trend was due to different loadings of the nanomaterials, as they close the pores of the membrane thus decreasing the flux. The performance of the membrane was monitored using batch adsorption studies. At optimum conditions (pH 6, initial concentration of 10 mg/L, and 40 minutes contact time) the batch studies revealed that M-1% performed better than M-0.2%, M-0.5% and M-0. This was due to the fact that dosing of the composites also revealed that it had more active sites to complex Pb(II) after 40 minutes of v adsorption. The kinetics studies have shown that the reaction between the Pb(II) and the membrane was chemisorption and it took place under pseudo second order reaction kinetic model and Langmuir isotherm. , M.Sc. (Nanoscience)
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Investigation of mechanical properties of polyethylene-based nano-composites

- Tebeta, Ronny Thapelo

  • Authors: Tebeta, Ronny Thapelo
  • Date: 2019
  • Subjects: Compressors , Carbon nanotubes , Nanocomposites (Materials) , Injection blow molding
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/418308 , uj:35461
  • Description: Abstract: Composites and nanocomposites materials are widely used in the newly developing technology for lightweight but strong materials such as in the automotive, aerodynamic, wind turbine and biomedical industries. The advantage of composites or nanocomposites is that they are made of a combination of two or more materials with distinct properties to achieve a new material with different properties from the constituent materials. This work covers the investigation of elastic properties of polymer-based nanocomposites whereby high-density polyethylene (HDPE) is reinforced with single-walled carbon nanotubes (SWCNT) at various weight fractions. SWCNTs nanoparticles are used with polymer HDPE to make composite which has remarkable properties, to enhance the elastic properties of polymer-based nanocomposites. The reason why SWCNTs nanoparticles were used as the strengthening material for HDPE, is because they contain high strength, high melting temperature and are easy to mix with plastics due to their size which is in Nanoscale. On the other hand, polymers are low in strength and lightweight materials which are easy to shape during the manufacturing process and they are inexpensive. Strengthening HDPE with SWCNTs nanoparticles result with a nanocomposite material which is high in strength and low in weight. This composite material holds a great potential to be used in the future for strong but lightweight components application. The objective of the current work was to prepare HDPE/SWCNTs nanocomposites using two different processing methods by reinforcing HDPE with SWCNT nanoparticles at the weight fractions of 0 wt%, 0.2 wt%, 0.4wt%, 0.6 wt%, 0.8wt%, and 1wt%. Then investigate its elastic properties at each weight fraction of SWCNTs and the effect of the processing techniques used on the elastic modulus of the composite. Injection and compression moulding were used to process the tensile test samples of HDPE/SWCNTs nanocomposites. The investigation was conducted used three approaches which include numerical, experimental and analytical. Numerical results were obtained using the finite element method (FEM) incorporated with represented volume element (RVE) to generate the HDPE/SWCNT nanocomposite model with the aid of ANSYS software. The simulations were made using two density-fractions of HDPE and SWCNTs at the same given weight fractions of SWCNTs nanoparticles per HDPE matrix. The modelled results showed that elastic modulus of HDPE/SWCNTs nanocomposite improved by 74 % at the SWCNTs weight fraction of 1 wt% for the density fraction of 1.8 and at the same weight fraction for the density fraction of 2 the improvement was found to be 56 % compared to pure HDPE. This shows that the low-density fraction of SWCNTs fibre and... , M.Ing. (Mechanical Engineering)
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Low temperature synthesis of multiwalled carbon nanotubes and incorporation into an organic solar cell

- Mugadza, Kudzai, Nyamori, Vincent O., Mola, Genene T., Simoyi, Reuben H., Ndungu, Patrick G.

N-Doped, B-Doped carbon materials and yolk-carbon shell nanostructures : synthesis, characterization and application for heteregeneous catalysis

- Nongwe Beas, Isaac

Phosphorylated carbon nanotube-cyclodextrin/silver-doped titania nanobiocomposites for water purification

- Leudjo Taka, Anny

  • Authors: Leudjo Taka, Anny
  • Date: 2018
  • Subjects: Water - Purification , Cyclodextrins , Titanium dioxide , Carbon nanotubes , Nanobiotechnology
  • Language: English
  • Type: Doctoral (Thesis)
  • Identifier: http://hdl.handle.net/10210/278734 , uj:29917
  • Description: Ph.D. (Chemistry) , Abstract: Nowadays, the shortage of water resources is the major concern around the world and especially in Southern Africa. The challenge is to develop an effective method to recycle wastewater through adequate treatment. That is to design a water treatment material able to remove the pollutants from wastewater effectively and efficiently to the accepted levels. In this regard, the aim of this research project was to develop a new nanomaterial which was used as adsorbent and disinfectant to remove all the three classes of water pollutants (inorganic, organic and pathogenic microorganism) from wastewater. In this study, phosphorylated multiwalled carbon nanotube-cyclodextrin/silver doped titania (pMWCNT-βCD/TiO2-Ag) was synthesized, using a combined process of amidation reaction, cross-linking polymerization and the sol-gel method. For a better evaluation of the target material, the insoluble nanosponges β-cyclodextrin (βCD) polymer and pMWCNT-βCD composite polymer were also synthesized for comparison purposes. The prepared nanostructured materials were fully characterized using thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), Brunauer-Emmett-Teller (BET) method, electron microscopy, and spectroscopy techniques. Fourier-transform infrared (FTIR) spectroscopy was used to confirm the presence of functional groups on the surface of modified MWCNTs, and the polymerization reaction. X-ray photoelectron spectroscopy (XPS) was employed to further confirm the presence of functional groups on the surface of the nanomaterials synthesized and to provide the percentage elemental composition with binding energies. Laser Raman showed the presence of MWCNT, βCD, and TiO2 in the nanocomposite. The anatase crystalline form of TiO2 in the samples synthesized was confirmed by X-ray diffraction (XRD) spectroscopy analysis. Transmission electron microscopy (TEM) analysis confirmed the structural morphology of the new biopolymer nanocomposite (pMWCNT-βCD/TiO2-Ag) as a sponge-like structure which showed a good dispersion of Ag nanoparticles. The BET surface area of the newly developed pMWCNT-βCD/TiO2-Ag was very high (352.55 m2/g), and this favored the use of this new nanomaterial as an adsorbent for the effective removal of pollutants from synthetic i.e. model wastewater and mine effluent samples...
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Phototherapy combined with carbon nanomaterials (1D and 2D) and their applications in cancer therapy

- Sundaram, Prabhavathi, Abrahamse, Heidi

  • Authors: Sundaram, Prabhavathi , Abrahamse, Heidi
  • Date: 2020
  • Subjects: Cancer , Carbon nanotubes , Graphene
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/455158 , uj:40275 , Citation: Sundaram, P. & Abrahamse, H. 2020. Phototherapy combined with carbon nanomaterials (1D and 2D) and their applications in cancer therapy.
  • Description: Abstract: Carbon‐based materials have attracted research interest worldwide due to their physical and chemical properties and wide surface area, rendering them excellent carrier molecules. They are widely used in biological applications like antimicrobial activity, cancer diagnosis, bio‐imaging, targeting, drug delivery, biosensors, tissue engineering, dental care, and skin care. Carbon‐based nanomaterials like carbon nanotubes and graphene have drawn more attention in the field of phototherapy due to their unique properties such as thermal conductivity, large surface area, and electrical properties. Phototherapy is a promising next‐generation therapeutic modality for many modern medical conditions that include cancer diagnosis, targeting, and treatment. Phototherapy involves the major administration of photosensitizers (PSs), which absorb light sources and emit reactive oxygen species under cellular environments. Several types of nontoxic PSs are functionalized on carbon‐based nanomaterials and have numerous advantages in cancer therapy. In this review, we discuss the potential role and combined effect of phototherapy and carbon nanomaterials, the mechanism and functionalization of PSs on nanomaterials, and their promising advantages in cancer therapy.
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Polyethersulfone (PES) membrane embedded with Fe/Ni nanoparticles decorated-carbon nanotubes (CNTs) for degradation of chlorinated organics in water

- Thatyana, Maxwell

  • Authors: Thatyana, Maxwell
  • Date: 2015-06-30
  • Subjects: Water - Purification - Chlorination , Water - Purification - Membrane filtration , Polymeric composites , Nanostructured materials , Carbon nanotubes
  • Type: Thesis
  • Identifier: uj:13655 , http://hdl.handle.net/10210/13839
  • Description: MSc. (Applied Chemistry) , Remediation of POPs particularly the chlorinated compounds in water is therefore crucial. This research work describes the modification of polyethersulfone (PES) thin-film membrane composite (TFC) with functionalised carbon nanotubes (f-CNTs) using the phase invasion method. The oxidised CNTs were successfully decorated with Zero-Valent (ZV) Fe/Ni nanoparticles for the adsorption and degradation studies of polychlorinated organic pollutants (in this case the dichlorodiphenyltrichloroethanes (DDTs)). The in situ modification procedure was carried out using different quantities (0.04 wt%, 0.1 wt% and 0.2 wt%) of Fe/Ni-f-CNTs nanohybrids dispersed in a DMAc solution and dipping the polyethersulfone powder into a suspension containing the Fe/Ni-f-CNTs to form a nano-composite membrane. The formed composite membrane characteristics were investigated with Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle (CA) and X-ray diffraction spectroscopy (XRD). The incorporation of nanohybrid in the PES membrane was found to increase the surface smoothness and the hydrophilicity of the composites. In addition, there was an increase in the adsorption of DDTs with increase in the nano-hybrid loading as indicated by the adsorption studies using the Langmuir isotherm and Freundlich isotherm studies. The data obtained from the batch studies closely fitted with the Langmuir isotherm based on the characteristic parameter RL found to lie within the standard range 0 < RL < 1 .
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Preparation characterization and properties of bionanohybrids based on biocompatible poly(glycolicacid)/polylactide blends and carbon nanotubes - towards orthopaedic applications

- Botlhoko, Orebotse Joseph

Promoting carbon nanotube interlinking using ion implantation and high pressures in a diamond anvil cell

- Kapesi, Liberty

  • Authors: Kapesi, Liberty
  • Date: 2018
  • Subjects: Carbon nanotubes , Physics
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/292625 , uj:31803
  • Description: Abstract: Carbon nanotubes (CNTs) possess extraordinary thermal and mechanical properties on an individual nanotube level. Gaining these benefits on a macro-scale has been elusive due to the poor nanotube linkages (tube-to-tube as well as wall-to-wall for multiwall CNTs). Hence, in this study, ‘defect decoration’ at various nanotube locations using boron ion-implantation was followed by high-pressure (HP) treatments in a diamond anvil cell (DAC). This was done to promote intra nanotube wall-to-wall and inter tube-to-tube interlinking in double wall carbon nanotubes (DWCNTs). The present study has shown, for the first time, the close-interval monitoring of the D band evolution with pressure up to 25 GPa, for DWCNTs, in spite of intense obscuring signals from the diamond window. Further, to the best of our knowledge, no other study on combined ion implantation pre-processing and subsequent pressurization to high pressures of DWCNTs has been reported. DWCNTs were pressurized up to 25 GPa at room temperature. Due to sample inhomogeneity it was necessary to use an appropriate large area scanning mode to obtain an average from 64 spectra per pressure. Vis-Raman spectroscopy (532 nm laser excitation) measurements were done at intervals of 2-3 GPa. A separate DAC containing boron ionimplanted DWCNT sample from the same batch as the reference (starting, non-implanted), was prepared. 11B+ ions of 150 keV per ion at a fluence of 5×1012 per cm2 were used in the implantation. The same probe and measurement protocols as for the reference sample were repeated in the HP Raman measurements on the implanted sample. The Raman probing depth is ~30 nm. Appropriate sample preparation, DAC loading and implantation procedures have been developed to ensure an unambiguous probing of the shallow implanted surface. In addition, UV-Raman (244 nm) measurements were done on recovered samples decompressed from 20 GPa as well as starting DWCNT material in search of the characteristic signature for sp3 bonds. The D to G+ (axial) band intensity ratio for implanted DWCNTs evolves with pressure following a trajectory consistent with an empirically determined trend for proliferation of sp3 bonds in carbon materials [A.C. Ferrari and J. Robertson, Phys. Rev. B 61, 14095 (2000)]. A maximum of ~10% volume fraction of sp3 bonds was determined. The pressure dependences of the G+ band position for implanted DWCNTs delineated three pressure regimes 0 ≤ P ≤ 3 GPa, 3 < P ≤ 11 GPa and P >11 GPa. The behaviour of the G+ band position with pressure indicates two competing mechanisms namely the proliferation of sp3 bonds and expected phonon mode hardening. Notable changes in the pressure dependences of the Raman spectral parameters of the D and G bands occur at low and higher critical pressure. The lower critical pressure for both implanted and unimplanted DWCNTs is 2-3 GPa. Due to introduction of nucleation sites as well as enhanced nanotube interaction in the implanted DWCNTs, the lower critical pressure for implanted DWCNTs corresponds to the onset in proliferation of sp3 bonding in the DWCNT structures followed by a subsequent saturation of sp3 formation beyond 9 GPa. The lower critical pressure for unimplanted DWCNTs is... , M.Sc. (Physics)
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Spark plasma sintering of multiwall carbon nanotubes reinforced titanium-aluminium-vanadium based nanocomposites

- Okoro, Avwerosuoghene Moses

  • Authors: Okoro, Avwerosuoghene Moses
  • Date: 2019
  • Subjects: Titanium-aluminum-vanadium alloys , Nanoparticles , Carbon nanotubes , Sintering
  • Language: English
  • Type: Doctoral (Thesis)
  • Identifier: http://hdl.handle.net/10210/413026 , uj:34780
  • Description: Abstract: Innovations in materials development has engendered the improvement of the properties of titanium alloys for diverse engineering applications. In this study, titanium alloy (Ti6Al4V) and multiwall carbon nanotubes (MWCNT) were mixed using shift-speed ball milling (SSBM) technique to achieve the uniform dispersion of MWCNT in the Ti6Al4V matrix. The starting and admixed powders were characterized using scanning electron microscopy equipped Energy dispersive X-Ray spectroscopy (SEM-EDS), X-ray diffraction (XRD), Raman spectroscopy and Transmission electron microscopy (TEM). Detailed TEM characterization was carried out to reveal the structural evolutions of the MWCNT during the dispersion process using selected area diffraction and fast Fourier transform pattern. The admixed powders were then consolidated using the spark plasma sintering machine (model HHPD-25, FCT GmbH Germany). Furthermore, various characterization technique such as XRD, SEM-EDS, optical microscopy (OM) was employed to understand the phase evolutions, morphology, microstructural changes and fractography of the fabricated nanocomposites. The mechanical properties of the fabricated materials were further investigated using the Vickers microhardness tester (FALCON 500 series) and the nanoindentation technique (ultra nanoindenter) UNHT. The study resulted in five (5) research articles, each article investigated the following respectively; (1) the previous works that have been conducted in SPS of titanium-based nanocomposites reinforced with MWCNT, (2) the dispersibility, structural evolutions and interfacial bonding of MWCNT in Ti6Al4V powders using the SSBM technique, (3) the evaluation of the influence of varying sintering temperature on the sintering and densification behaviours and microhardness of the fabricated alloy and nanocomposites, (4) the effects of MWCNT addition on the change in microstructures and mechanical properties of the fabricated nanocomposites, and (5) the influence of MWCNT on the nanomechanical properties of the fabricated nanocomposites. During the dispersion process, the Raman and XRD pattern of the admixed powders showed that mechanical stresses were induced on the walls of the nanotubes which does not result in defects on the MWCNT. Optimal dispersion of MWCNT was achieved on the nanocomposite grades comprising of 0.5 and 1.0 wt.% nanotubes. Additionally, the dispersibility decreased with the increase in concentration of the MWCNT in the Ti6Al4V matrix. Meanwhile, the nanocomposite grades with higher fraction of MWCNT experienced higher deformation of the nanotubes during the dispersion process. The optimal dispersion of MWCNT in Ti6Al4V matrix with minimal... , D.Ing. (Metallurgy)
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Synthesis and characterisation of ³²P labelled bisphosphonates conjugated carbon nanotubes as a potential chemo and radiotherapeutic system for the treatment of secondary bone cancer

- Dlamini, Njabuliso Lucia

  • Authors: Dlamini, Njabuliso Lucia
  • Date: 2012-05-02
  • Subjects: Bone cancer treatment , Bisphosphonates , Carbon nanotubes
  • Type: Thesis
  • Identifier: uj:2235 , http://hdl.handle.net/10210/4675
  • Description: M.Sc. , The statistical proof that most forms of cancer metastasize to bone has redirected the focus of secondary bone cancer to probe into the most efficient forms of treatment. Due to the fact that secondary bone cancer delocalizes to bone, chemotherapy has been established as an efficient form of treatment. Bisphosphonates is one chemotherapeutic agent that has shown a great potency in treating bone related sicknesses. Bisphosphonates are analogues of pyrophosphates that are characterized by the presence of two P-C bonds. They have a very high affinity for bone undergoing renewal and are thus able to inhibit tumour induced resorption. Bisphosphonates’ efficiency is however reduced due to that they have a low molecular weight hence are excreted before reaching targeted sites. In this study, an attempt to improve the efficiency was done by providing carbon nanotubes (which were synthesized in our laboratories) as delivery systems. By conjugating bisphosphonates onto carbon nanotubes the molecular weight was increased. Bisphosphonates conjugated carbon nanotubes have been radiolabelled to increase their anticancer activity. By exploiting the Enhanced Permeability Retention (EPR) effect and the high energy electrons from the radioisotope (³²P), it is anticipated that bone metastasis will be successfully treated by the ³²P labelled bisphosphonates carbon nanotube conjugates. Successful synthesis of bisphosphonates conjugated carbon nanotubes was confirmed by several characterization techniques namely: the Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Raman spectroscopy, Thermal Gravimetric Analysis (TGA), Electron Dispersive X-ray (EDX), and the Fourier Transmission Infrared spectroscopy (FT-IR). Oxidation and bisphosphonates conjugation onto carbon nanotubes were further confirmed by the Raman, TGA, FT-IR, EDX and the SXPS (Scanning X-ray photoelectron spectroscopy) Successful radiolabelling was determined by a liquid scintillation counter (LSC).
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Synthesis and characterization of carbon nanospheres and carbon nanotubes conjugated bisphosphonates as potential drugs for the treatment of secondary bone cancer

- Dlamini, Njabuliso Lucia

Synthesis and modifications of polymer-based carbon/metal organic framework composites for hydrogen storage applications

- Molefe, Lerato

  • Authors: Molefe, Lerato
  • Date: 2019
  • Subjects: Polymeric composites , Carbon nanotubes , Carbon composites , Nanocomposites (Materials)
  • Language: English
  • Type: Doctoral (Thesis)
  • Identifier: http://hdl.handle.net/10210/417836 , uj:35402
  • Description: Abstract: The South African energy landscape is dominated by carbon dioxide (CO2) emitting coal combustion which is currently plentiful and cheap however because of its finite nature, it will soon diminish. With the current growing population and increasing energy need, research scientists all over the world are continuously working towards shifting to cleaner renewable energy sources of which hydrogen (H2) is a promising candidate. Hydrogen has a high gravimetric energy density than any other fuel and its combustion in pure oxygen only produces water vapour and heat. However, since it is very light and as a result has a low volumetric energy density, its storage is very difficult. Generally, adsorbents materials such as metal-organic frameworks (MOFs) such as Materials Institute Lavoisier (MIL-101(Cr)) and Universitetet i Oslo (UiO-66(Zr)) as well as porous carbons such as zeolite templated carbon (ZTC) have been well investigated for H2 storage due to their unique properties such as extremely high surface areas and ultrahigh porosities. However, their great potential in H2 storage applications is limited by their lack of immediate processability, because they are obtained as fine powders in their as-synthesised form. For these materials to gain practical applications in H2 storage they must be shaped into mechanically stable and easy to handle bodies like monoliths. The process of shaping MOFs and carbon powders often includes the use of various non-porous polymers and inorganic materials as binders and that often results in pore-blocking effects and low H2 uptake... , Ph.D. (Chemistry)
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