Synergism in Binary (MWNT, SLG) Nano-carbons in Polymer Nano-composites: A Raman Study

2013 ◽  
Vol 1505 ◽  
Author(s):  
Peng Xu ◽  
James Loomis ◽  
Ben King ◽  
Balaji Panchapakesan
Keyword(s):  
Mechanical Strength ◽  
Polymer Composites ◽  
Load Transfer ◽  
Synergistic Effects ◽  
Cooperative Behavior ◽  
Single Layer Graphene ◽  
Polymeric Chain ◽  
Uniaxial Tensile ◽  
Advanced Composites ◽  
Nano Carbon

ABSTRACTLoad transfer and mechanical strength of reinforced polymers are fundamental to developing advanced composites. This paper demonstrates enhanced load transfer and mechanical strength due to synergistic effects in binary mixtures of nano-carbon/polymer composites. Different compositional mixtures (always 1 wt. % total) of multi-wall carbon nanotubes (MWNTs) and single-layer graphene (SLG) were mixed in polydimethylsiloxane (PDMS), and effects on load transfer and mechanical strength were studied using Raman spectroscopy. Significant shifts in the G-bands were observed both in tension and compression for single as well binary nano-carbon counterparts in polymer composites. Small amounts of MWNT0.1 dispersed in SLG0.9/PDMS samples (subscripts represents weight percentage) reversed the sign of the Raman wavenumbers from positive to negative values demonstrating reversal of lattice stress. A wavenumber change from 10 cm-1 in compression (-10% strain) to 10 cm-1 in tension (50% strain), and an increase in elastic modulus of ∼103% was observed for MWNT0.1SLG0.9/PDMS with applied uniaxial tension. Presence of MWNTs in the matrix reduced the segmental polymeric chain length and provided limited extensibility to the chains. This in turn eliminated compressive deformation of SLG and significantly enhanced load transfer and mechanical strength of composites in tension. The orientation order of MWNT with application of uniaxial tensile strain directly affected the shift in Raman wavenumbers (2D band and G-band) and load transfer. It is observed that the cooperative behavior of binary nano-carbons in polymer composites resulted in enhanced load transfer and mechanical strength. Such binary compositions could be fundamental to developing advanced composites.

Anisotropically Functionalized Nanotube Anchors for Improving the Mechanical Strength of Immiscible Polymer Composites

2020 ◽  
Author(s):  
Lawrence Barrett ◽  
Fatoumata Ide Seyni ◽  
Mallikharjuna Rao Komarneni ◽  
John A. Zapata-Hincapie ◽  
Daniel T. Glatzhofer ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
Polymer Composites ◽  
Immiscible Polymer

Tensile Properties of Epoxy Matrix Reinforced with Fique Fabric

2020 ◽  
Vol 1012 ◽  
pp. 14-19
Author(s):  
Michelle Souza Oliveira ◽  
Fabio da Costa Garcia Filho ◽  
Fernanda Santos da Luz ◽  
Artur Camposo Pereira ◽  
Luana Cristyne da Cruz Demosthenes ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
Polymer Composites ◽  
Natural Fiber ◽  
Volume Fraction ◽  
Fiber Reinforced Polymer ◽  
Epoxy Composites ◽  
Synthetic Fiber ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites

Composite materials are being extensively studied for ballistic armor. Their main advantage is connected to the possibility of deeply reducing weight and costs by maintaining high performances in terms of strength and security. Epoxy composites are reinforced with natural fibers which are replacing other synthetic reinforcement materials. Composites are prepared using polymers as matrix material because of ease of production with different reinforcements. The mechanical strength of the natural fiber reinforced polymer composites has been compared with synthetic fiber reinforced polymer composites and it is found that for achieving equivalent mechanical strength of the material, the volume fraction of the natural fiber should be much higher than synthetic fiber. This work being an experimental study on untreated “as received” fique fabric-reinforced epoxy composites, to demonstrate the potential of this renewable source of natural fiber for use in a number of applications.

Morphological Effects on the Materials Properties of Polyimides

1993 ◽  
Vol 323 ◽  
Author(s):  
T. W. Poon ◽  
J. Leu ◽  
Y. S. Kang ◽  
H. C. Liou ◽  
P. S. Ho
Keyword(s):  
Mechanical Strength ◽  
Deformation Energy ◽  
Thermomechanical Properties ◽  
Film Plane ◽  
Polymeric Chain ◽  
Material Strength ◽  
Strong Material ◽  
Rigid Rod ◽  
Interfacial Strain ◽  
Metal Polymer

AbstractWe have carried out a comparative study on the thermomechanical properties and interfacial fracture for two polyimides, a rigid-rod like BPDA-PDA and a flexible-chain PMDA-ODA. This study is focused on the correlation between material strength and polymeric chain morphology. A strong correlation was observed, with high chain packing order giving rise to strong material strength. Quantitatively, the mechanical strength of PMDA-ODA thin films along the direction tangential to the film plane is about 1/3 of that of BPDA-PDA, and its thermal expansivity 1.5 to 5 times larger. For fracture, the mechanical strength of the polyimide plays a different role. A softer polyimide such as PMDA-ODA will strengthen the confinement exerted by the metal lines with smaller interfacial strain, thereby decreasing the amount of deformation transmitted through the interface into the metal, and shifting the onset of delamination to a higher strain on the entire structure. However, the same softer polyimide layer also induces a larger amount of plastic deformation, leading to fracture of the film at a smaller strain. For a strong metal/polymer interface, the strength of the interfacial bonds is sufficient to hold the interface intact while the polymer near the interface deforms plastically because it is much softer mechanically than the metal. This continues until the deformation energy accumulated in the polymer is sufficient to delaminate the interface. Under this condition, the locus of failure will be determined by the relative fracture toughness of the polymer compared with the interface, which may very well occur in the polymer very close to the interface.

High Dynamic Mechanical Strength of Zirconium-Based Bulk Amorphous Alloys

1998 ◽  
Vol 554 ◽  
Author(s):  
Tao Zhang ◽  
Akihisa Inoue
Keyword(s):  
Residual Stress ◽  
Mechanical Strength ◽  
Amorphous Alloys ◽  
Compressive Residual Stress ◽  
Bending Strength ◽  
Tensile Fracture ◽  
Uniaxial Tensile ◽  
Cast Sample ◽  
Bulk Amorphous Alloys ◽  
Squeeze Cast

AbstractA bulk amorphous Zr55Al10Ni5Cu30 alloy prepared by squeeze casting was found to exhibit high mechanical strength values, i.e., uniaxial tensile fracture strength (σt) of 1850 MPa, three-point bending strength (σb) of 3200 MPa, bending fatigue strength (σf) of 1100 MPa, Charpy impact fracture energy (Ef) of 135 kJ/m2 and fracture toughness of 68 MPa√m. The σb, σf and Ef are about two times higher than those for the corresponding bulk amorphous alloys prepared by unidirectional solidification and powder consolidation techniques, though the σt of the squeeze cast sample is higher by about 15 % than those for the other samples. The remarkable increases in the σb, σf and EF are presumably due to the introduction of high compressive residual stress of about 1240 MPa in the outer surface region only for the squeeze cast sample. The finding of the effectiveness of the compressive residual stress on the increase in the mechanical strength under the bending stress mode is important and expected to be widely used as a new strengthening mechanism for bulk amorphous alloys, as is the case for reinforced oxide glasses subjected to strengthening treatment.

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