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Masgahoni N.,Virginia24061 | Al-Haik M.,Virginia24061
Polymer Composites | Year: 2014

The ability to engineer the fiber/matrix interface in carbon fiber reinforced polymers (FRPs) can be achieved by introducing a nanophase between the fiber and the matrix, which could functionally-grade the material properties and enhance the load transfer. Many nanomaterials when employed exhibited significant interfacial improvements such as carbon nanotubes and nanofibers. In lieu of carbon nanomaterials, we suggest growing zinc oxide (ZnO) nanowires on the interface of woven carbon fibers prior to forming the composite. This study shows that, when grown on the surface of carbon fibers, the ZnO nanowires have enhanced both the on-axis strength and stiffness by 20 and 7.5%, respectively, and the off axis strength by 14%. The experimental results showed also that the interlaminar shear strength increased by 88% and the damping capabilities by 51%. Furthermore, this novel interface could also offer embedded energy harvesting functionality through the piezoelectric properties of ZnO. © 2014 Society of Plastics Engineers. Source


Boroujeni A.Y.,Virginia24061 | Nelson A.J.,Virginia24061 | Al-Haik M.,Virginia24061
Polymer Composites | Year: 2015

In this study carbon nanotubes (CNTs) were incorporated into carbon fiber reinforced polymer composites (CFRPs) by growing them on the surface of PAN-based carbon fibers utilizing a relatively low temperature technique. The effect of various surface treatments of the carbon fibers on the in-plane and out-of-plane mechanical performance of the hybrid CFRPs (e.g. exposure to or shielding against elevated temperatures, patterned vs. unpatterned growth of the CNTs over the carbon fibers) were investigated. The in-plane quasi-static mechanical properties and out-of-plane dynamic properties of the hybrid CFRPs were examined utilizing tension and dynamic impact tests, respectively. To study the progressive damage mechanism of the hybrid CFRPs, spherical punch tests as well as X-ray radiography of the impact damaged hybrid CFRPs were carried out. The results revealed that the strength and impact energy dissipation of the CFRPs improved by 11% and 127%, respectively, utilizing patterned growth of CNTs on the surface of the carbon fibers. © 2015 Society of Plastics Engineers. Source


Alipour Skandani A.,Virginia24061 | Yari Boroujeni A.,Virginia24061 | Kalhor R.,Virginia24061 | Case S.W.,Virginia24061 | Al-Haik M.,Virginia24061
Polymer Composites | Year: 2014

The insufficient viscoelastic resistance of fiber reinforced plastics can be retrofitted by the addition of more rigid nano fillers to the polymer matrix. In this study, carbon fibers plies were grafted with zinc oxide (ZnO) nano-rods and the hybridized reinforcement was utilized in laminated composites. Flexural creep tests were carried out using dynamic mechanical analysis (DMA) and the time/temperature superposition principle was employed for accelerated testing. To verify the applicability of TTPS, prolonged stress relaxation tests were also carried out in flexural mode. Data from the DMA flexural creep tests revealed that the whiskerization of carbon fibers with ZnO nano rods reduced the creep compliance by 23% at elevated temperatures and prolonged durations. Also, the relaxation data confirmed the applicability of TTPS to these hybrid composites. The stress relaxation modulus improved by 65% in comparison to composites based on neat carbon fibers. © 2014 Society of Plastics Engineers. Source

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