Showing papers by "Marwan Al-Haik published in 2018"
01 Jan 2018
TL;DR: In this article, the authors reviewed recent efforts for achieving synergy of the electrical conductivity in nanocomposites based on carbon nanofillers and concluded that the particle agglomeration, poor dispersion, interfaces, and lack of proper functionalization severely affect the microstructure and hence the properties of the hybrid polymeric composites and are the root causes for the conflicting results in the literature.
Abstract: This chapter reviews recent efforts for achieving synergy of the electrical conductivity in nanocomposites based on carbon nanofillers. Hybrid polymeric nanocomposites based on carbon nanotubes (CNTs) and graphite nanoplatelets (GNPs) are of particular interest for their enhanced transport properties, over mono-nanofiller composite systems. Besides reviewing the effects of the processing of nanocomposites on archiving synergy of electrical conductivity, we also review several recently developed computational models based on percolation analysis. The results suggest that both the models, and the experimental observations, confirm the presence of the synergy effect for the electrical properties of the hybrid composites. Particularly, several computational and experimental studies suggest incorporating a miniscule amount of auxiliary nanofiller boosts the electrical conductivity of the hybrid composites by several orders of magnitudes. The review affirms that the particle agglomeration, poor dispersion, interfaces, and lack of proper functionalization severely affect the microstructure and hence the properties of the hybrid nanocomposites and are the root causes for the conflicting results in the literature.
20 citations
18 Jan 2018
TL;DR: In this article, different configurations of hybrid composites based on carbon fibers with different combinations of ZnO nanorods and Bucky paper were fabricated, and the composites were tested mechanically via tensile and dynamic mechanical analysis (DMA) tests to examine the effect of different nanoadditives on the stiffness, strength and the damping performance of the hybrid composite, which suggest that there are certain hybrid composite combinations that could lead to the development of highly multifunctional composites with better strength, stiffness, damping and electrical conductivity.
Abstract: The quest for multifunctional carbon fiber reinforced composites (CFRPs) expedited the use of several nano reinforcements such as zinc oxide nanorods (ZnO) and carbon nanotubes (CNTs). Zinc oxide is a semi-conductor with good piezoelectric and pyroelectric properties. These properties could be transmitted to CFRPs when a nanophase of ZnO is embedded within CFRPs. In lieu of ZnO nanorods, Bucky paper comprising mat of CNTs could be sandwiched in-between composite laminae to construct a functionally graded composite with enhanced electrical conductivities. In this study, different configurations of hybrid composites based on carbon fibers with different combinations of ZnO nanorods and Bucky paper were fabricated. The composites were tested mechanically via tensile and dynamic mechanical analysis (DMA) tests to examine the effect of the different nanoadditives on the stiffness, strength and the damping performance of the hybrid composites. Electrical resistivities of the hybrid composites were probed to examine the contributions of the different nanoadditives. The results suggest that there are certain hybrid composite combinations that could lead to the development of highly multifunctional composites with better strength, stiffness, damping and electrical conductivity.
14 citations
TL;DR: In this article, ZnO nanorods were grown on the surface of carbon fibers to create hybrid reinforcements, and two different techniques were utilized to pre-deposit the znO seeding layer on the carbon fibers; ZnOs nanoparticles/solution mixture airbrush spraying, and magnetron sputtering.
Abstract: Integrating nano-sized reinforcing materials into carbon fiber polymer composites (CFRPs) could enhance several aspects of their mechanical performance; e.g., interfacial strength, delamination resistance and vibrations attenuation. In this study, ZnO nanorods were grown on the surface of carbon fibers to create hybrid reinforcements. The hydrothermal synthesis of ZnO nanorods was tuned such that relatively long (>2.0 μm) nanorods can be grown. This synthesis technique requires pre-deposition of a thin seeding layer of ZnO particulates on the carbon fibers to initiate the ZnO nanorods growth. Depending on the method by which the seeding layer is deposited, the grown ZnO nanorods could display different morphologies. In this study, two different techniques were utilized to pre-deposit the ZnO seeding layer on the carbon fibers; ZnO nanoparticles/solution mixture airbrush spraying, and magnetron sputtering. The carbon fibers pre-coated with the airbrush spraying method yielded forests of randomly oriented ZnO nanorods, while the fibers pre-coated via the sputtering technique exhibited radially aligned ZnO nanorods forests. Hybrid CFRPs were fabricated based on the aforementioned carbon fiber fabrics and tested via 3-point bending dynamic mechanical analysis (DMA) and quasi-static tension tests. The loss tangent of the CFRPs, which delineates the damping capability, increased by 28% and 19% via radially and randomly grown ZnO nanorods, respectively. The in-plane tensile strength of the hybrid CFRPs were improved by 18% for the composites based on randomly oriented ZnO nanorods over the carbon fibers. The fractographs of the tension samples were also captured to reveal the role of the long ZnO nanorods in the in-plane performance of the hybrid CFRPs.
12 citations