Abdirahman Ali Yussuf

Bionanocomposites of regenerated cellulose/zeolite prepared using environmentally benign ionic liquid solvent

Bionanocomposite films based on regenerated cellulose (RC) and incorporated with zeolite at different concentrations were fabricated by dissolving cellulose in 1-ethyl-3-methylimidazolium chloride (EMIMCl) ionic liquid using a simple green method. The interactions between the zeolite and the cellulose matrix were confirmed by Fourier transform infrared spectra. Mechanical properties of the nanocomposite films significantly improved as compared with the pure regenerated cellulose film, without the loss of extensibility. Zeolite incorporation enhanced the thermal stability and char yield of the nanocomposites. The scanning electron microscopy and transmission electron microscopy showed that zeolite was uniformly dispersed in the regenerated cellulose matrix. In vitro cytotoxicity test demonstrated that both RC and RC/zeolite nanocomposite films are cytocompatible. These results indicate that the prepared nanocomposites have potential applications in biodegradable packaging, membranes and biomedical areas.

Effect of fiber reinforcement on mechanical and thermal properties of poly( ɛ -caprolactone)/poly(lactic acid) blend composites

Optimized palm press fiber composites of poly(ɛ-caprolactone)/poly(lactic acid) were produced and their mechanical and thermal properties were studied. The composites were melt blended using twin screw extruder and test specimens were produced by injection molding. The composites mechanical and thermal performances were tested using standard methods. The incorporation of dicumyl peroxide as compatibilizer significantly increased the tensile strength, flexural modulus and impact strength of the composites as compared to the uncompatibilized composites. Crystallization temperature of the composites initially increased after which it dropped as fiber load increased. The composites melting point and percentage crystallinity slightly decreased as fiber load increased.

Comparative studies of mechanical properties of poly (e-Caprolactone) and poly (lactic acid) blends reinforced with natural fibers

The mechanical properties of polycaprolactone/polylactic acid, blend reinforced with Dura fiber and Tenera fibre palm press fibers have been comparatively studied. Melt blending of the composites was carried out using twin screw extruder after which test specimens were produced by injection molding. Dicumyl peroxide (DCP) was used as a cross linker in the blend composites. The composites mechanical performances were tested using standard methods. Field emission scanning electron microscope (FESEM) and Fourier transform infrared spectroscopy were used to characterize the blend composites. The flexural modulus of the composites increased by 98%, while the impact strength increased by 52%. The flexural strengths of both fibers were enhanced generally. FESEM micrographs of the blend showed two-phase structure in the absence of DCP. The incorporation of DCP resulted in good interfacial adhesion as revealed by the micrographs and evidenced in the improved mechanical properties.

Synthesis and Characterization of Conductive Polypyrrole: The Influence of the Oxidants and Monomer on the Electrical, Thermal, and Morphological Properties

Conductive polymer, polypyrrole (PPy), was synthesized by chemical oxidative polymerization technique for a period of four hours at room temperature using pyrrole monomer (mPPy) in aqueous solution. Different oxidants such as ferric chloride (FeCl3) and ammonium persulphate (N2H8S2O8) and surfactant sodium dodecyl sulphate (C12H25NaO4S) were used. The produced PPy samples were characterized by using different techniques such as the electrical resistivity by four probe technique, thermogravimetry analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The performance of the oxidants has been investigated and compared. It was found that both oxidants, FeCl3 and N2H8S2O8, have decreased electrical resistivity as a function of temperature, which means increased conductivity. However, FeCl3 has achieved better performance than N2H8S2O8, where it has achieved a lower resistivity of about 60 ohms at room temperature, which indicates higher conductivity of PPy samples with FeCl3 as an oxidant. Similarly, further investigation of FeCl3 oxidant has been conducted by varying its concentration, and its influence on the final properties was reported. It has been observed that the morphology of PPy samples has a significant influence on the conductivity. It was found that 0.1 M and 0.05 M concentrations of FeCl3 oxidant and monomer, respectively, have achieved better thermal stability, which is FeCl3/mPPy ratio of 2 as an optimum value. FTIR and XRD results confirmed the structural formation of polypyrrole from pyrrole monomer during the synthesizing process.

Effect of crude oil and well stream chemical on glass fiber epoxy composite pipes

Abstract Glass-reinforced epoxy (GRE) pipes are used as an alternative to carbon steel pipes in desert oil field applications owing to their good properties such as chemical resistance, thermal resistance and mechanical properties. In the desert oil field service, the pipes are exposed to different harsh environmental conditions such as high temperature, humidity and ultraviolet radiation. The harsh environmental conditions can affect the properties of GRE pipes, which, in turn, can impact their performance. The present study covers the effects of environment factors such as crude oil and well stream chemicals on the properties of GRE pipes. The pipe samples were aged in wet crude, effluent water and scale inhibitor to simulate the exposure to desert oil field service. The aged samples were evaluated for their mechanical properties, thermal stability and chemical resistance. The compositional change in the composite structures was characterized using Fourier transform infrared spectroscopy and matrix deterioration by scanning electron microscopy. Swelling studies revealed no significant diffusion by the chemical media. Tensile testing showed a slight change in tensile strength with aging in crude oil. In addition, all the pipe samples showed adequate thermal stability to withstand harsh environmental conditions.

A Comparison of the Polymer Matrix Behavior and Mechanical Properties of the Glass Reinforced Plastics and Glass Reinforced Epoxy Pipes under Different Oil Field Chemicals

Fiber reinforced composite material is used widely in oil fields for its high specific strength and resistance to corrosion. Glass reinforced plastics (GRP) and Glass reinforced epoxy (GRE) pipe samples were investigated under oil field conditions. The samples were subjected to ultraviolet radiation, moisture and elevated temperature using accelerating weathering machine and then aged in different environments encountered in oil well streams and characterized by using Scanning Electron Microscopy (SEM). The surface morphology was analyzed and the images produced from wet crude and effluent water has shown different degree of deformation of the glass fiber and debonding with the polymer matrix. The tensile and modulus properties were also evaluated and effect of ageing found to be more pronounced in the case of wet crude especially for the GRE. The study revealed some tendency of GRP samples to reform the polymer matrix interface with the glass fiber after weathering. The assessment of physical properties provided information about the structural stability of composite pipes under harsh environments, which in turn can impact their overall performance and service life.