Showing papers by "Mou'ad A. Tarawneh published in 2012"

Mechanical properties of TPNR-MWNTs-OMMT hybrid nanocomposites

Abstract: This paper discusses the processing of a hybrid of TPNR-MWNTs-OMMT nanocomposites with different percentages of filler to determine the optimum mechanical properties of the hybrid nanocomposites. Three types of hybrid nanocomposites with various MWNTs-OMMT compositions (1%wt MWNTs+3%wt OMMT), (2%wt MWNTs+2%wt OMMT) and (3%wt MWNTs+1%wt OMMT) were prepared. The OMMT layers were found to be separated further with higher nanotubes content as exhibited by X-ray diffraction. The result of tensile test showed that tensile strength and Young's modulus increase in the presence of nanotubes and maximum value were obtained for the nanocomposites with highest nanotubes (3%wt) which increased about 33% and 36%, respectively compared with pure TPNR matrix. On other hand, the elongation at break considerably decreased with increasing the percentage of MWNTs. TEM micrographs revealed aspect ratio and fillers orientation in the TPNR matrix also promoted strongly to interfacial adhesion between fillers and the matrix which contributed significantly to the improvement of the mechanical properties

Optimization of Tensile Properties of Epoxy/Nanoclay/MWNT Nanocomposites by Taguchi Method

Abstract: In this study, nanoclay and multi-wall carbon nanotubes have been used as a dual filler in an epoxy matrix. In the design of the experiment (DOE) the Taguchi Method was selected to study the effect of the factors involved in this study. The effect of the clay/MWNT ratio, types of solvent, clay cation, composition of LENR, cure time and cure temperature on tensile properties of the epoxy nanocomposites were investigated. The confirmation experiment obtained from Taguchi analysis, achieved 57% improvement in tensile strength. X-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed the presence of intercalated and aggregated structures. Due to the lower crosslink density of the system, a decrease in decomposition temperature and glass transition temperature was observed in the optimum sample.

Thermal Conductivity, Thermal Diffusivity and Specific Heat of TPNR Hybrid Nanocomposites at Different Temperatures

Abstract: This paper discusses the inclusion of hybrid nanofillers nanoclay and multi-walled carbon nanotubes (MWNTs) as reinforcing agents to improve the thermal properties of TPNR The laser flash technique was also employed to determine the thermal conductivity, thermal diffusivity and specific heat capacity of the nanocomposite Two types of hybrid nanofillers were introduced into TPNR, which are untreated hybrid composites (UTH) prepared from MWNTs (without acid treatment)-nanoclay and treated hybrid composites (TH), consisting of acid treated MWNTs and nanoclay The thermal properties of treated hybrid composites are better than untreated hybrid composites The thermal conductivity of untreated hybrid composites that were sintered at 30 to 150 oC did not show a monotonous change with MWNTs as the filler has a high thermal conductivity compared to nanoclay The results showed that the thermal diffusivity decreased with the increasing of temperature The specific heat of all the measured samples increases linearly with the measured temperature from 30°C to 150°C

The effect of MWCNTs on the rubber-toughened epoxy nanocomposites

Abstract: This paper investigated the mechanical properties of rubber-toughened epoxy resins reinforced with multi-walled carbon nanotubes (MWCNTs). Rubber-toughened epoxy resins were prepared using the mechanical stirring method and molded into samples with compression molding with different amount of MWCNTs (0.5wt%–3wt%). The bending modulus, bending strength and impact strength increased by almost 125%, 20% and 35% respectively, at 1%wt MWCNTs compared with rubber-toughened epoxy. A scanning electron micrograph (SEM) confirms the effect of good dispersion of MWCNTs and their interfacial bonding in the matrix.

Investigations on Metal Injection Molding of 316L SS Using Thermoplastic Natural Rubber (TPNR) Binder as a New System

Abstract: Metal injection molding (MIM) is a near net-shape manufacturing technology that is capable of mass production of complex parts cost-effectively. The unique features of the process make it an attractive route for the fabrication of the new binder system since the success of MIM process is dependent on the outward appearance of the resultant feedstock. Thermoplastic natural rubbers (TPNR) blends consist of thermoplastics, such as polyethylene (PE), alloyed with natural rubber (NR) with different thermoplastic to NR ratios. The soft grade TPNR is produced by blends with compositions richer in rubber while the harder grades can contain up to about 30 % NR. This study investigates the influence of new binder system consisting of TPNR on injection parameter, density of injected molded specimen and changes during solvent extraction. Results show that TPNR plays an important role as a good binder system and shortens the solvent extraction process.

The effect of ultrasonic treatment and gamma radiation on the thermal conductivity of TPNR hybrid nanocomposites

Abstract: This paper discusses the effect of Gamma radiation and ultrasonic treatment time on hybrid nanofillers nanoclay and multi-walled carbon nanotubes (MWCNTs) as reinforcing agents to improve the thermal conductivity of TPNR. The laser flash technique was also employed to determine the thermal conductivity of the hybrid nanocomposite. The thermal conductivity of hybrid nanocomposites that were sintered at 30 to 150 °C did not show a monotonous change with MWCNTs as the filler has a high thermal conductivity compared to nanoclay by using different dose of gamma radiation or with different time of ultrasonic treatment. TEM results showed a combination of intercalated-exfoliated structure of OMMT and the dispersion of MWCNTs in the TPNR composite. The probability that hybrid nanoparticles form a network depends on the interaction between the particles, on their shape (aspect ration), preparation conditions and on their inter-particle distance will control the thermal conductivity of the hybrid nanocomposite.

Application of Taguchi's Approach in the Optimization of Tensile Properties of Epoxy/Nanoclay/MWCNT Nanocomposites

Abstract: This paper reports the improvement in tensile strength of epoxy by using binary hybrid nanocomposites of nanoclay and multi-wall carbon nanotube using a solution casting method. The effect of clay/MWCNT ratio, types of solvent, clay cation, composition of LENR, cure time and cure temperature on the tensile properties of epoxy nanocomposites were investigated using Taguchi Method. Orthogonal array L27 is chosen for sample preparations. Analysis of Mean (ANOM) and Analysis of Variance (ANOVA) was used to identify the dominant factors and the optimum values of clay/MWCNT ratio and settings of other process parameters. Confirmation of experiment was performed with the optimum parameter settings and the measured mechanical properties were compared with the predicted results. Morphologies of the fracture surface of MWCNT/epoxy nanocomposites was observed by scanning electron microscope (SEM). Transmission electron microscope (TEM) and X-ray diffraction (XRD) test were employed to analyse the dispersion structure in the modified samples.