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A review of polydimethylsiloxane - volatile organic compounds interactions

  • Authors: Muzenda, Edison
  • Date: 2012
  • Subjects: Polymers , Volatile organic compounds , Polydimethylsiloxane , Gas liquid chromatography
  • Type: Article
  • Identifier: uj:4682 , ISBN 978-93-82242-07-9 , http://hdl.handle.net/10210/10455
  • Description: This paper is a review on the interactions of certain volatile organic compounds with polydimethylsiloxane using the gas liquid chromatographic technique (GLC). The interactions reviewed here were studied in the form of specific retention volumes. Only single stationary phases were considered in this review. For similar systems, the retention data agrees very well. This review has shown that the GLC is a rapid and convenient method to obtain thermodynamic data for polymeric systems. This work is very useful in the determination of phase equilibrium in form of infinite dilution activity coefficients necessary for the design of absorption and stripping columns for the abatement of volatile organic compounds from contaminated air streams.
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A revisit and review of experimental variables affecting chromatographic organics - polydimethylsiloxane interactions

A revisit and review of experimental variables affecting chromatographic organics - polydimethylsiloxane interactions

Alginate beads supporting nanocomposites incorporating cyclodextrin polymers and fe/ni decorated carbon nanotubes for the removal of 2,4,6-trichlorophenol in water

  • Authors: Kera, Nazia Hassan
  • Date: 2013-12-09
  • Subjects: Water - Purification - Organic compounds removal , Nanocomposites (Materials) , Nanotubes , Cyclodextrins , Polymers
  • Type: Thesis
  • Identifier: uj:7841 , http://hdl.handle.net/10210/8736
  • Description: M.Sc. (Chemistry) , The quality of fresh water is deteriorating due to pollution by a wide range of substances as a result of industrial, agricultural, domestic, mining and other anthropogenic activities. Even at trace levels in water, some pollutants are toxic to organisms through acute or chronic effects or through bioaccumulation. Conventional water treatment is often ineffective at removing pollutants to the ultra-low levels required by water quality standards and other technologies employed to remove toxic compounds from water have high capital and operating costs and other disadvantages. There is therefore an ongoing need to develop low-cost technologies that are effective for the removal of toxic pollutants from water. In our laboratories, iron and nickel (Fe/Ni) decorated carbon nanotube (CNT)/cyclodextrin polymers (β-CDs) showed promising results in previous studies carried out for the degradation and removal of toxic organic pollutants in water. However, the powder form of the polymer makes its direct application in water treatment difficult. The leaching of metal nanoparticles and carbon nanotubes from the polymer into the water being treated is also of concern due to their potential toxicity. In this study, alginate beads were investigated as supports for two kinds of nanocomposites, Fe/Ni decorated carbon nanotubes and Fe/Ni decorated carbon nanotube/cyclodextrin polymers. Alginate beads were selected as supports to render the nanocomposites more conducive towards water treatment applications since they are easy to handle and recover from water and are also stable supports that can prevent the leaching of nanomaterials into treated water.
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Application of cyclodextrin nanoporous polymers in the removal of organic pollutants from water

  • Authors: Sithole, Soraya P.
  • Date: 2009-04-30T09:21:20Z
  • Subjects: Water purification , Cyclodextrins , Polymers , Organic water pollutants
  • Type: Thesis
  • Identifier: uj:8318 , http://hdl.handle.net/10210/2446
  • Description: M.Sc. , The removal of organic pollutants from industrial and municipal water is a great challenge to water providers worldwide. Some of these pollutants are very toxic and pose serious health risks to both humans and animals. Additionally, the presence of organic pollutants in the water often leads to the corrosion of turbines used for power generation at power stations. This obviously makes the power generation process less efficient and thus has cost implications, especially for the end user. Besides the corrosion of turbines, organic water pollutants impact on the cost of generating clean water. To this end, municipalities and industries sourcing water from Rand Water’s treatment plants and Eskom’s power stations (coal-fired power station) may be plagued by high water costs. Geosmin and 2-MIB are detectable by the human nose at concentration levels as low as 10 ng/L. These common water pollutants and are renowned for causing bad taste and odour in drinking water. Although geosmin and 2-MIB do not pose any serious health risks to humans, they impact on the aesthetic and consumer acceptability of drinking water. Currently available technologies such as activated carbon are unable to remove these pollutants to low levels (i.e. ppb levels). In our laboratories, we have found cyclodextrin-based polyurethanes to be effective in the removal of a range of organic pollutants from water to the desired ppb levels. However, these investigations were confined to water samples deliberately spiked with specific pollutants and have not been proven with "real" water samples. We sought to integrate data accumulated in the laboratory by testing and applying these polymers on a larger scale and on real systems. Cyclodextrin (CD) polymers were employed in the removal of 2-MIB, geosmin and other organic pollutants from water. The water was sampled from a coal-fired power station and Zuikerbosch Water Treatment Plant (Rand Water). After using Solid Phase Microextraction (SPME) for the extraction of organic pollutants from the water samples the organic pollutants were identified and quantified using Gas chromatography-mass spectrometry (GC-MS). The new cyclodextrin polymer technology was compared with treatment methods currently applied at both the power station and treatment plant. To determine the environmental friendliness of this technology, polymer degradation studies were also carried out. These entailed performing soil burial tests prior to the characterization of the polymers. Thermogravimetric analysis (TGA), Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM) and Braunner Emmet Tellet (BET) analysis were used for the characterization of the polymers. The techniques were also used to determine if any degradation modifications occurred on the polymeric material. The findings of the study are summarized below: • SPME extraction and GC-MS analyses of geosmin, 2-MIB and other pollutants were successfully accomplished. • The cyclodextrin polymers were effective in the removal of geosmin and 2-MIB (up to 90%) from water sampled at Zuikerbosch water treatment plant. The polymers remained effective (90%) in the absorption of geosmin and 2-MIB even when the water samples were spiked with a competing pollutant (i.e. humic acid). Activated carbon has been noted to have reduced adsorption capacity when humic acid is present in water. • The polymers demonstrated the ability to remove as much as 90% of organic pollutants from raw water compared to the 50% removed by the polyelectrolyte and optimum minimal polyaluminium chloride employed at the coal-fired power station. Analyses of the samples using TOC before and after treatment were accomplished. Reduction in the TOC was noted at the different sampling points after Eskom’s water treatment regime. • Results from the study indicated that the β-CD TDI polymers underwent a greater weight-loss during soil burial when first digested in sulphuric acid (ca. 50% maximum mass loss). On the other hand, β-CD HMDI polymers appeared to be unaffected by predigestion and experienced the same amount mass loss for the digested and undigested polymers (ca. 30% maximum mass loss). SEM studies revealed changes in the surface morphology of the polymers. Moreover, thermogravimetric analysis (TGA) gave an indication of polymer degradation under all soil burial conditions the polymer was subjected to.
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Die effek van polivinielalkohol-adsorpsie op die mikroflottasie van piriet en talkgesteentes

Immobilization of silver nanoparticles decorated on dendritic polymer nanofibrous membrane for antibacterial properties

  • Authors: Maziya, Khona Primrose
  • Date: 2019
  • Subjects: Silver - Environmental aspects , Nanoparticles - Environmental aspects , Dendrimers , Polymers
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/417518 , uj:35362
  • Description: Abstract: The shortage of clean water is one of the major concerns affecting several regions worldwide. This coupled with the alarming rate of bacterial contamination caused by poor sanitation, agricultural runoffs and wastewater discharges has led to public health and economical concerns. Water containing pathogenic bacteria causes several diseases such as skin infections and diarrheal diseases (cholera, dysentery, typhoid fever, etc.) upon contact and ingestion. Conventional treatment methods including chlorination have been unsuccessful in the complete eradication of bacterial contaminants and further cause disinfection by-products that are carcinogenic in nature. This has urged researchers to device improved treatment methods such as membrane technology for the removal of bacterial contaminants in water whilst addressing the concerns that come with the use of conventional treatment methods... , M.Sc. (Chemistry)
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Ion-imprinted polymers for mercury and chromium selective removal from aqueous solutions and detection using electrochemical methods

  • Authors: Velempini, Tarisai Phillipa
  • Date: 2018
  • Subjects: Molecular imprinting , Chromium , Mercury , Polymers , Imprinted polymers , Water - Purification - Chromium removal
  • Language: English
  • Type: Doctoral (Thesis)
  • Identifier: http://hdl.handle.net/10210/278799 , uj:29925
  • Description: Ph.D. (Chemistry) , Abstract: One of the main challenges in heavy metal adsorption is the lack of selectivity (or specificity) for a pollutant by an adsorbent. This lack of selectivity may compromise the adsorption efficiency and the effectiveness of the adsorbent for the adsorption of a target pollutant. The solution to this problem lies in imprinting a memory for the target pollutant on the adsorbent so that when the adsorbent is required for adsorption it will choose to bind with the target pollutant even in the presence of other pollutants. In this study, ion-imprinted polymers (IIPs) were synthesized for the selective removal of Cr(VI) and Hg(II) from aqueous solutions. Furthermore, sulphur-containing ion imprinted polymers (S-IIPs) were used in the selective adsorption of Hg(II) and in the electrochemical detection of Hg(II) from water. The ion-imprinted polymers were derived from sodium carboxymethyl cellulose and synthesized via a surface imprinting method. In the first part of this thesis, IIPs were applied for Cr(VI) adsorption. The ligand, ethylenediamine was used for complexation with the Cr(VI). For comparative purposes, non-ion imprinted polymers (NIPs) were also synthesized. The obtained IIPs and NIPs were characterized by various techniques such as X-ray photoelectron spectroscopy (XPS), 13C Nuclear magnetic resonance (13C NMR) analysis, Energy dispersive X-ray spectroscopy (EDS) and Brunauer-Emmet-Teller (BET) surface area analysis. EDS and XPS spectrums showed the presence of nitrogen in the IIPs and NIPs. The surface area of the IIPs was larger than that of NIPs an aspect which had a significance in the adsorption performances for the Cr(VI). The adsorption of Cr(VI) was favourable at low pH, while the desorption process was best at high pH. The kinetics of adsorption followed a pseudo-second-order model while the Langmuir adsorption isotherm provided the best fit with a maximum adsorption capacity of 177.62 mg g−1 at 25 oC. The Langmuir adsorption capacity for the non-imprinted polymers (NIPs) at 25 oC was 149.93 mg g−1. Thermodynamic parameters indicated an endothermic process and spontaneous adsorption of Cr(VI) on the polymers. The selectivity of the IIPs was remarkable compared to the NIPs. Furthermore, the IIPs adsorbent was successfully recycled 5 times using 0.1 M NaOH as a leachate; 98% Cr(VI) was desorbed during the last adsorption-desorption cycle. In the second part of the study, sulphur containing ion imprinted polymers (S-IIPs) were applied for the uptake of Hg(II) from aqueous solution. Cysteamine, which was used as the...
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New insights on the interaction between thiophene derivatives and Au surfaces: the case of 3,4-ethylenedioxythiophene and the relevant polymer.

  • Authors: Terzi, F. , Pasquali, L. , Montecchi, M. , Nannarone, S. , Viinikanoja, A. , Seeber, R. , Aaritalo, T. , Salomaki, M. , Lukkari, J. , Doyle, B.P.
  • Date: 2011
  • Subjects: Thiophene derivatives , Polymers , Polycrystalline substrates
  • Type: Article
  • Identifier: uj:5797 , ISSN 1932-7455 , http://hdl.handle.net/10210/7805
  • Description: The nature of the interface between electrogenerated poly(3,4-ethylenedioxythiophene) and the Au substrate is studied in detail. In particular, the adsorption of the relevant monomer, namely, 3,4-ethylenedioxythiophene, is investigated and compared with that of other thiophene derivatives. Different deposition procedures have been adopted: very thin films of the thiophene derivatives have been obtained through chemisorption processes from vapor and liquid phases, on Au polycrystalline substrates, Au nano particles possessing different size, and a Au(111) single crystal. Different techniques, operating both in situ and ex situ, have been employed for the characterization of these deposits, that is, X-ray photoemission and surface enhanced Raman spectroscopy. The results show that the poly(3,4-ethylenedioxythiophene)/metal interface is far from being simply constituted by unreacted molecules in contact with the substrate; rather, the formation of oligothiophene species and sulfur atoms at the interface has been ascertained.
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Novel porous organic polymer supported gold-based nanocatalysts for production of biopolymer chemicals

  • Authors: Sebati, Ngwanamohuba Wilhemina
  • Date: 2019
  • Subjects: Biomass chemicals - Synthesis , Polymers , Catalysis
  • Language: English
  • Type: Doctoral (Thesis)
  • Identifier: http://hdl.handle.net/10210/418742 , uj:35515
  • Description: Abstract: Catalytic synthesis of value-added chemicals from renewable biomass-derived platform chemicals is an important way to reduce current dependence on fossil-fuel resources. The main objective of this study was to synthesize magnetic functionalized porous organic polymers (POPs), gold incorporated POPs and bifunctional gold incorporated POPs acid catalysts and use them for the catalytic upgrade of biomass derived model compounds to valuable chemicals. The high surface area, stable and amorphous nanoporous polytriphenylamine polymer (PPTPA) was synthesized as a POPs based support under a microwave assisted method. The synthesized PPTPA was sulfonated with chlorosulfonic acid to introduce acidic groups on the surface of the material to form SPPTPA acid catalysts which were further incorporated with magnetic Fe3O4 nanoparticles to form FeSPPTPA catalysts. The neat PPTPA support and SPPTPA materials were incorporated with gold nanoparticles to form AuPPTPA and bifunctional AuSPPTPA nanocatalysts. The morphological characterization showed that the prepared materials showed nanofiber-like, flake-like and nanorods morphologies. The magnetic solid acid catalysts (FeSPPTPA) successfully dehydrated fructose to 5-hydroxymethyl furfural (HMF) as a valuable compound with highest HMF yield of 96.61% and the best catalyst could be reused for 4 consecutive catalytic runs. The magnetic solid acid catalysts (FeSPPTPA) also showed that levulinic acid could be converted to diacids as the products even though levulinic acid could not be fully converted to possible products under the reaction conditions used. , Ph.D. (Chemistry)
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On organics – polydimethylsiloxane interactions : influence of experimental variables

Phosphorylated nanoporous β-cyclodextrin polymers: synthesis, characterization and their application in water purification

  • Authors: Simelane, Siphamandla
  • Date: 2012-06-07
  • Subjects: Polymers , Water purification , Removal of organic pollutants , Removal of inorganic pollutants , Cyclodextrins
  • Type: Thesis
  • Identifier: uj:8698 , http://hdl.handle.net/10210/5051
  • Description: M.Sc. , This study was carried out to investigate the removal of organic and inorganic pollutants from water using phosphorylated and nonphosphorylated cyclodextrin polymers. The β-cyclodextrin was functionalized using various phosphorylating agents and the derivatives obtained were characterised with Fourier Transform-Infrared (FT-IR), Nuclear Magnetic Resonance (NMR) spectroscopy and mass spectrometry. These derivatives were polymerized using hexamethylene diisocyanate (HMDI) as a cross-linking agent. The polymers were obtained in good yields ranging from 72 % to 93 %. They were characterised using Fourier Transform-Infrared (FT-IR), Scanning Electron Microscopy/Energy Dispersive X-ray spectroscopy (SEM)/EDXS), Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) to confirm the presence of phosphorus groups after polymerization. The removal of cadmium (II), chromium (III), trichlorophenol (TCP) and pentachlorophenol (PCP) was investigated in batch-mode experiments under varying conditions of pH, initial concentration and contact time. The concentration of heavy metal ions in water was determined using inductively-coupled plasma-optical emission spectroscopy (ICP-OES) and that of organic pollutants was determined using ultraviolet-visible (UV-Vis) spectroscopy. The polymers were found to adsorb up to chromium (III) better than cadmium (II) at pH 6.5. The maximum percentage removal of chromium (III) ranged between 83.9 % and 95 % whilst that of cadmium (II) ranged from 24.5 % to 39 %. There was no significant difference in the adsorption capacity of phosphorylated and phosphorus-free polymers in the removal of metals. However, phosphorylation improved the efficiency of the polymers in the removal of chlorophenols. The maximum percentage removal of TCP ranged from 17 % to 80.1 % whilst that of PCP ranged from 23 % to 77.2 %. The results obtained in this study demonstrate that the polymers are promising materials for the removal of Cr (III), TCP and PCP from water.
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Polymer-zeolite nanocomposites : preparation, characterization and application in heavy-metal removal

  • Authors: Mthombo, Sydney Thabo
  • Date: 2013-09-11
  • Subjects: Nanocomposites (Materials) , Polymers , Zeolites , Heavy metals - Absorption and adsorption , Water - Purification
  • Type: Thesis
  • Identifier: uj:7734 , http://hdl.handle.net/10210/8603
  • Description: M.Sc. (Chemistry) , Polymer nanocomposites are a new class of composites in which at least one dimension of the particles dispersed in the polymer matrix is in the nanometer range. Recently, different types of zeolite minerals, either natural (Clinoptilolite, chabazite, modernite) or synthetic (A-type, X-type, Y-type) are being employed as particulate fillers into the polymer matrix. Owing to their unique ion exchange phenomenon, zeolites have been widely studied as heavy metal adsorbents, but very few researchers have focused on the sorption of heavy metal ions on zeolite-filled polymer nanocomposites...
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Polymeric nitrogen donor macro(meso)porous sorption materials for selected transition metals

Polysulfone/β-cyclodextrin polyurethane mixed-matrix composite nanofiltration membrane for water treatment

Synthesis and characterization of nano-engineered chalcogen materials for environmental and biomedical applications

  • Authors: Kumar, Neeraj
  • Date: 2017
  • Subjects: Nanostructured materials , Polymers , Inorganic cyclic compounds , Chalcogens
  • Language: English
  • Type: Doctoral (Thesis)
  • Identifier: http://hdl.handle.net/10210/243095 , uj:25092
  • Description: Ph.D. (Chemistry) , Abstract: Nano-engineered chalcogen materials have garnered importance among the researchers across all scientific disciplines because of their interesting properties as well the possibility to tailor their electric, optical, thermal and mechanical properties via controlling shape and size. Various chalcogen based nanostructured materials such as Co3O4, MoO3, MoS2, NiS, WS2, WSe2, MoSe2, Bi2Te3, Ag2Te etc have found improved applications in energy conversion and storage devices, electronics, catalysis, sensors, solid lubricants and topological insulators etc. Still, these nanostructured materials have not been much explored for environmental and biomedical aspects although they have immense potential. The expensive and complicated fabrication techniques and perplexity of surface modification are the critical reasons which limit their utility in desired applications. Most of the previously reported synthesis techniques have also no control over issues such as structural composition, variant size and morphologies. However, different shapes and size dependent properties of nano-engineered chalcogen materials are yet to be explored. Thereby, this study addressed the facile strategies to design and develop new materials and structures with controlled morphologies, size, and composition of nano-engineered chalcogen materials via the wet chemical route. The evolved physiochemical properties based on their structural dimensions were also investigated. The effect of various reaction parameters such as the ratio of precursors, precursor concentrations, the role of stabilising/capping agent and new precursors on the composition and morphological evolution of the chalcogen based nanomaterials have been systematically explored. The developed liquid phase synthesis methodologies of nano-engineered chalcogen materials were facile, economical, energy efficient and eco-friendly. The structural, compositional and morphological features of fabricated chalcogen based nanomaterials were studied using various analytical instruments such as SEM/EDX, HRTEM, XRD, TGA, XPS, UV-Vis, FT-IR and Raman. Furthermore, this research also focused on harnessing the full potential of these synthesised nanomaterials in environmental and biomedical applications based on the information of physiochemical properties. Some applications that are covered in the environmental field are adsorption, photocatalysis and nanophosphors, whereas the biomedical field includes mainly cytotoxic behaviour of nanomaterials. The highlights of results obtained from the PhD study are summarised as follows. Part I presents a study of the anions ratio effect of acetate and nitrate ions on the formation of the different morphology of ZnO crystals in presence of NaOH and HMTA. The...
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Tegnologie-ontwikkeling vir 'n buigbare amorfe silikon-sonsel-vervaardigingsproses

  • Authors: Saunderson, Jacobus Daniël
  • Date: 2012-08-14
  • Subjects: Amorphous semiconductors , Silicon , Polymers , Solar cells , Chromogenic compounds
  • Type: Thesis
  • Identifier: uj:9207 , http://hdl.handle.net/10210/5657
  • Description: Ph.D. , The aim of this study was the development of a new technology for the manufacturing of amorphous silicon (a-Si:H) solar cells on flexible substrates. Kapton R , a commercially available polymer, was used as a substrate to this end. The use of such a polymer, as opposed to glass, results in dramatic savings and also affords the possibility for technological innovation. From the start the project was planned to develop and commission a medium-scale pilot plant manufacturing process. The project thus consisted of two sections: the design, fabrication and implementation of a large-area deposition system, as well as research and development of the materials and cells. A pilot plant was developed and successfully implemented. The optimization of the reactor resulted in very homogeneous materials with good electrical- and optical characteristics. The individual materials were optimized and incorporated into the standard cell configuration (on glass). This process was then transferred to kapton and the configuration was optimized. The use of kapton, as opposed to glass, implies the growth of silicon on a metal film on the kapton. This process leads to a number of phenomena occurring in cells on kapton which do not occur in standard cells on glass. The phenomena include the crystallization of a-Si:H at low temperatures, degradation of the material properties and unwanted microstructure. The origin of these phenomena can be linked to the high occurence of metal/Si-interdiffusion. It was found that this inter-diffusion can be decreased by the insert i on of a thin ZnO buffer layer between the back metal contact and the a-Si:H. The flexible cells were successfully developed and optimized for large areas. An operational manufacturing process was thus developed and the product of this study can now be applied successfully in practical applications.
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The incorporation of CdS and CdSe nanoparticles into poly (methyl methacrylate) and/or polyethylene oxide polymer fibres via electrospinning technique

  • Authors: Mthethwa, Thandekile Phakamisiwe
  • Date: 2012-05-03
  • Subjects: Nanoparticles , Polymers , Semiconductor nanoparticles , Electrospinning , Fibers , Quantum dots
  • Type: Thesis
  • Identifier: uj:2252 , http://hdl.handle.net/10210/4690
  • Description: M.Sc. , This report illustrates the synthesis and characterization of CdS and CdSe nanoparticles in TOPO, HDA and hexamethylenediamine. The prepared nanoparticles were characterized using UV-visible and photoluminescence spectrophotometers for optical properties, transmission electron microscopy for shapes and sizes as well as powder X-ray diffractometer for structural analysis. The effect of monomer concentration and temperature were investigated on the growth of nanocrystals. The monomer concentration was varied by changing the amount of stabilizer. The particle sizes increased with an increase in monomer concentration. Higher monomer concentration resulted in polydispersed nanoparticles due to faster uncontrolled growth. Increasing the temperature resulted in a faster growth thus increasing the size of the particles. The growth also affected the shapes of the particles as the particles tend to grow anisotropical ly at higher monomer concentration and high temperatures. The formation of tretrapods at high temperatures was due to a kinetically driven reaction as a result of increased temperature. Hexamethylenediamine was found to be a poor capping agent for the prepared CdS nanoparticles. The particles prepared in the compound agglomerated at all temperatures used in preparation. Such results were associated with lower steric hindrance due to a shorter molecular chain. The polymer nanofibres were fabricated via electrospinning technique while varying the concentrations of the polymer solutions. Solutions of low viscosity gave beaded fibres as mixtures of droplets and fibres due to the collection of wet fibres. An increase in the concentration (viscosity) of the solutions resulted in the deposition of solid fibres with bigger diameters. The TGA results show that PMMA electrospun fibres demonstrate a significant increase in thermal stability compared to the powder polymer. However the changes were very minimal on the PEO fibres. CdS and CdSe nanoparticles were incorporated into PMMA and PEO and electrospun to fabricate composite fibres. The incorporation of the quantum dots caused an increase in the viscosity of the solutions and resulted in the collection of fibres with spiral morphology. However this increase of concentration caused an increase in the diameters of the composite fibres as evaluated from the SEM analysis. The EDS analysis showed the presence of Cd, S, and Se elements in the composite fibres due to the presence of CdS and CdSe. The XRD analysis of the composite showed no effect of the quantum dots on the amorphous peak of the PMMA. However on the PEO it showed a decrease in the intensity as the peaks as they become broader due to the decrease of crystallinty. The FTIR spectra showed that the presence of the quantum dots in the polymers on both PMMA and PEO. The optical analysis showed absorption and emissions peaks on the composites fibres due to the showed incorporated light emitter. These peaks were not affected by any change in the concentrations as a result of increased wt % of the quantum dots. Thermal analysis of the composite fibres demonstrates an increase in the thermal stability of the polymers after the incorporation of the quantum dots. Very small changes were observed for the quantum dots doped-PEO material compared to the doped PMMA. DSC analysis showed an increase in the glass transition temperature of the PMMA with increasing wt % of the CdS and CdSe. The addition of CdS and CdSe nanoparticles into PEO caused a decrease in the melting temperature of the polymer due to a decrease in the polymer crystallinity.
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