Synthesis and Physicochemical Behaviour of Polyurethane-Multiwalled Carbon Nanotubes Nanocomposites Based on Renewable Castor Oil Polyols

Polyurethanes (PUs) are high performance materials, with vast industrial and engineering applications. In this research, effects of Multiwalled Carbon Nanotubes (MWCNTs) on physicochemical properties of Castor Oil based Polyurethanes (COPUs) were studied. MWCNTs were added in different weight percentages (0% to 1% wt) in a castor oil based polyurethane (COPUs-MWCNTs) nanocomposites. The composition, structure, and morphology of polyurethanes were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), and element detection by energy dispersive spectroscopy (EDX) analysis, respectively. Thermal stability was studied by thermogravimetric analysis (TGA). Barrier properties and surface area studies were investigated by nitrogen permeability machine and BET technique. Mechanical properties were calculated by tensile universal testing machine. Results showed well dispersed MWCNTs in polyurethane matrix at different weight percentages. The best results were obtained with 0.3 wt% of MWCNTs in the composite. Surface area studies revealed presence of very few pores which is in a good agreement with barrier permeability, reduced up to ~68% in 1 wt% and ~70% in 0.5 wt% of MWCNTs in polymer matrix, with respect to pure COPUs samples

Mechanical and thermal properties of the waste low and high density polyethylene-nanoclay composites

In extension with the previous work, recycling of the waste polyolefins by dissolution/reprecipitation method, has been investigated. The goal of study was to explore the influence of organo-modified/unmodified sodium montmorillonite clays, on the behaviours of waste polyolefins inclusive low density polyethylene (LDPE) and high density polyethylene (HDPE). 1-5 wt % of unmodified (MMT) and Organo-modified clay (OMMT) were added to the polyolefins, to prepare polyolefin-clay nanocomposites by melt intercalation method. X-ray diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM) were used to estimate the dispersion of clay in the polymer matrices and the morphology of nanocomposites. Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) were used to analyse the change in the thermic properties of the waste polyolefins nanocomposites. The XRD and FESEM results showed an intercalated structure in the HDPE and LDPE with Organo-clay nanocomposites, whereas no exfoliation was observed with unmodified clay in both waste HDPE and LDPE, respectively. DSC and TGA, showed an improved thermal behaviours in the HDPE/Organo-clay nanocomposites (3 wt%) clay loading. Melting temperature and crystallization percentage were observed to increase in 1, 2, and 3 wt% loadings. In waste LDPE/clay nanocomposites, no improvement was established in the thermal stability

Synthesis and Physicochemical Behaviour of Polyurethane-Multiwalled Carbon Nanotubes Nanocomposites Based on Renewable Castor Oil Polyols

Polyurethanes (PUs) are high performance materials, with vast industrial and engineering applications. In this research, effects of Multiwalled Carbon Nanotubes (MWCNTs) on physicochemical properties of Castor Oil based Polyurethanes (COPUs) were studied. MWCNTs were added in different weight percentages (0% to 1% wt) in a castor oil based polyurethane (COPUs-MWCNTs) nanocomposites. The composition, structure, and morphology of polyurethanes were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), and element detection by energy dispersive spectroscopy (EDX) analysis, respectively. Thermal stability was studied by thermogravimetric analysis (TGA). Barrier properties and surface area studies were investigated by nitrogen permeability machine and BET technique. Mechanical properties were calculated by tensile universal testing machine. Results showed well dispersed MWCNTs in polyurethane matrix at different weight percentages. The best results were obtained with 0.3 wt% of MWCNTs in the composite. Surface area studies revealed presence of very few pores which is in a good agreement with barrier permeability, reduced up to ~68% in 1 wt% and ~70% in 0.5 wt% of MWCNTs in polymer matrix, with respect to pure COPUs samples

Synthesis and Characterization of Polyurethane– Organoclay Nanocomposites Based on Renewable Castor Oil Polyols

In this study, castor oil-based polyurethanes–organoclay (COPUs-Cloisite 30B) nanocomposites are synthesized by mixing polypropylene glycol polyol and dehydrated castor oil (15 %), enforced with C30B nanofillers, at different weight percentages. The physico-chemical behaviors were evaluated by Fourier transform infrared spectroscopy, Fourier scanning electron microscopy, scanning electron microscopy and X-ray diffraction. Thermal stability was found improved up to ~30 °C in the sample with 5 wt% of C30B. Tensile properties depicted an improvement of ~240 % in tensile strength and decrease of ~30 % in elongation with 5 wt% organoclay, respectively. Improved physico-chemical properties of COPUs-C30B signify the usage of COPUs-C30B in the industrial and commercial applications, i.e. coatings, adhesives and automotive applications

Pure Polyurethane and Castor Oil Based Polyurethane: Synthesis and Characterization

In this study, the physico-chemical properties of high performance polyurethane synthesized from poly propylene glycol (PPG) in comparison with a combination of PPG and castor oil, is studied using the in-situ polymerization technique. The variations in properties of both types of polyurethanes are evaluated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and the thermogravimetric analysis (TGA) technique. Tensile strength properties were investigated by film tensile testing equipment. The results indicated the presence of large -CH stretching in the castor oil mixed polyurethane with a larger oxidative thermal stability over pure PPG polyurethanes. The tensile properties were found to be almost comparable in pure and mixed polymers, signifying the usage of mixed polymers in the future to overcome the environmental and economic crisis in polyurethane synthesi

Iron oxide magnetic nanoparticles: a short review

Magnetic nanoparticles have been enjoying great importance and wide scale applications during the last two decades due to their specific characteristics and applications. Iron oxide magnetic nanoparticles with appropriate surface chemistry have been implied in numerous applications such as biomedicine and cancer therapy, catalysis and in magnetic separation techniques. This review summarizes recent commercial, industrial and bio-engineering applications and brief study of the methods for the preparation of iron oxide magnetic nanoparticles with a control over the size, morphology and the magnetic properties. Some future applications of microwave irradiation for magnetic particle synthesis are also addressed

Effect of Potassium Permanganate on Tensile Properties of Sugar Palm Fibre Reinforced Thermoplastic Polyurethane

Background: The high-performance engineering products derived from natural resources are in great demand worldwide, based on renewability and environmental problems. Method: The outcome of Potassium Permanganate (KMnO4) treatment on the tensile behaviours of treated Sugar Palm Fibre (SPF) with 6% NaOH reinforced thermoplastic polyurethane composites was investigated. The sugar palm fibres were treated by 6% NaOH solution, followed by KMnO4 surface treatment of the alkali treated sugar palm fibres. Three different concentrations of KMnO4 (i.e. 0.033, 0.066, and 0.125 %) were applied in the treatment. The extruder and hot press machines were used to mix the sugar palm fibres and polyurethane resin, to get the desired polyurethane composites. Tensile behaviours including (tensile strength and modulus, and the elongation at break) were investigated by following the ASTM D-638 standard. Findings: The highest tensile strength recorded was 8.986 MPa with KMnO4 concentration of 0.125 %, with 6 % alkali pre-treatment. Therefore, the KMnO4 concentration ∼0.125 % exhibited best results for tensile test. Improvements: This study aids an improvement in the alkaline activation method for the TPU/SPF composite fabrication

Systematic review of the preparation techniques of iron oxide magnetic nanoparticles

Abstract Magnetism being one of the oldest scientific disciplines has been continuously studied since 6 th century BC, which still offers scientific innovations today in realm of nanomagnetism. Iron oxide nanomaterials have been growing excessive importance because of their magnetic characteristics and wide applications. Iron oxides magnetic nanoparticles with appropriate surface chemistry are prepared either by wet chemical method such as colloid chemical or sol-gel methods or by dry processes such as vapour deposition techniques. This review summarizes comparative and brief study of the methods for the preparation of iron oxide magnetic nanoparticles with a control over the size, morphology and the magnetic properties. Applications of microwave irradiation for magnetic particle synthesis are also addressed

Wet Chemical Approach for Vanadium Doped Maghemite (Fe2-xVxO3) Nanocrystals

Background: Nanomaterials are widely synthesized by wet chemical routes. Magnetic nanoparticles with size ranging from 2 to 20 nm are of significant importance, resulting in a unique magnetic property of the nanoparticles. Maghemite nanostructures with partially disordered (Fe3+)[Fe5/3⁏1/3]O4 structures, undergo cation-insertion reactions without resorting to a drastic change in the material composition. Tailoring the superparamagnetic properties of nanoparticles by doping with transition metals, such as vanadium could be advantageous, as it would provide control over properties that are important for biological applications, such as magnetization dependent changes in temperature, relaxivity, and hysteresis. Method: We describe the obtention of vanadium doped maghemite (Fe2-xVxO3) from colloidal suspensions of vanadium and iron salts, using a precipitation–annealing method. A single step simpler synthesis scheme has been proposed in this work, with annealing temperature (350 °C), for a short period of time (~ 15 minutes), in order to achieve smaller in size but developed nanocrystals. Results: Superparamagnetic vanadium doped maghemite with particles (~8 nm) size has been synthesized. For the first time, vanadium up to 5 mol% has been doped on maghemite nanocrystals and characterized successfully for the presence of stable V3+. These results open a new era of vanadium applications in industrial Nanosciences; possessing superparamagnetic properties. Conclusion: A wet chemical route to direct the synthesis of vanadium doped γ- Fe2O3 nanocrystals, has been studied. The doping controls the crystallite size by occupying the vacant octahedral spaces available in the cubic system (space group P4332) maghemite crystals. High surface area magnetic particles, with an average size of ~8 nm were obtained