Mohamed H. Gabr

Effect of different types of aramid fibres on mechanical and thermal properties of nano-cellulose composites for vehicle applications

Natural-fibre composites have been embraced by car manufacturers and suppliers for door panels, seat backs, headliners, package trays, dashboards, and interior parts. Natural fibres offer such benefits as reductions in weight, cost, and CO2. Eco-friendly green/composites were fabricated from nano-cellulose and bacterial cellulose (BC) reinforced by aramid fibres (AF). The purpose of this study is to propose an effective form of AF as reinforcement in cellulose composites instead of expensive conventional materials for interior car parts. Technora (AFT) and Kevlar29 (AFK) with fibre length 1 mm and 5 mm (AFT1, AFT5, AFK1, and AFK5) were used as reinforcement. These materials were characterised by different techniques, namely SEM, TGA, tensile, bending, and hardness tests. All composites showed good dispersion for fibres and strong adhesion between the fibres and the matrix. The composites prepared with BC displayed better flexural and Youngs modulus, hardness and significant decrease for the coefficient of thermal expansion.

Mechanical, thermal, and interfacial shear properties of polyamide/nanoclay nanocomposites: Study the effect of nanoclay on the micromechanism of fracture

There are increasing interests in using thermoplastics to replace thermosets to laminate fabrication due to their advantages such as high toughness, shorter manufacturing cycles, and reprocessing possibilities. The aim of the current study is to select appropriate thermoplastic nanocomposites, which fit the requirements of carbon fiber (CF) composites in the automotive industry. In order to achieve the target, this research has investigated the effect of nanoclay on the mechanical, thermal, and interfacial properties with de-sized CF of polyamide (PA6) composites. PA6/clay composites were characterized by different properties, namely, bending, tensile, impact, heat distortion temperature, interfacial shear stress, and scanning electron microscope. The micromechanism of plastic deformation after bending failure of PA6-clay nanocomposites is examined with different contents of nanoclay to correlate the microstructures with the mechanical properties. The results revealed that with 3% organo-clay filler content, flexural strength and modulus improved significantly by 42% and 52%, respectively, which could be explained by scanning electron microscopy images that show rougher fracture surface with adding clay into the PA6 matrix. The increased surface roughness implies that the path of the crack tip is distorted because of the silicate nano-layer, making crack propagation more difficult. The interfacial shear strength for 1 wt% of nanoclay was about the same as the neat PA6 but decrease dramatically with increasing contents of nanoclay.

Novel multifunctional polyamide composites produced by incorporation of AlTi sub-microparticles

The potential of using of sub-microalumina/titanium particles as a reinforcement that can produce multifunctional polymer composites was explored. Novel multifunctional composites have been developed by incorporating sub-micro-alumina/titanium particles into polyamide6. The composites were investigated for their thermal, viscoelastic, water uptake and mechanical properties, as a function of alumina/titanium concentration. A detailed study of the morphological observation by scanning electron microscope was used to correlate the microstructures to the mechanical properties. Flexural testing shows that the flexural modulus and strength of the composite are improved by 22%, and 15%, respectively, with incorporating 10 wt% alumina/titanium. In addition, the impact strength was improved by about 19%. Furthermore, 10 wt% alumina/titanium increases the interfacial shear strength of polyamide6 by about 23%.

Mechanical and Morphology Properties of Cellulose Nanocomposites

Cellulose nanofibers and their composites have a great deal of attention because of their abundance, biodegradability, high strength and stiffness, low weight, relatively low price, and the related characteristics such as a very large surface-to-volume ratio and outstanding mechanical, electrical, and thermal properties. Such new high-value materials are the subject of continuing research and are commercially interesting in terms of new products from the pulp and paper industry and the agricultural sector. This chapter summarizes (i) the progress in nanocellulose preparation into polymer matrix with a particular focus on microfibrillated cellulose and also discusses recent developments in bio-nanocomposite fabrication based on nanocellulose, (ii) the progress in the reinforcement of the carbon fiber/epoxy composites using nanocellulose as a hybrid reinforcement, (iii) the improvement in the mechanical properties of carbon fiber/epoxy composites using nanocellulose as hybrid reinforcement, and (iv) the morphology of CF/epoxy composite reinforced with nanocellulose showing the effect of nanocellulose on the fiber/matrix adhesion.