scholarly journals Effects of CNT Diameter on the Uniaxial Stress-Strain Behavior of CNT/Epoxy Composites

2008 ◽  
Vol 2008 ◽  
pp. 1-6 ◽  
Author(s):  
N. Yu ◽  
Y. W. Chang
Keyword(s):  
Epoxy Matrix ◽  
Weight Fraction ◽  
Uniaxial Stress ◽  
Epoxy Composites ◽  
Percentage Increase ◽  
Matrix Composites ◽  
Stress Strain ◽  
Strain Behavior ◽  
Young’S Moduli ◽  
Micromechanics Models

The present work studies the effects of the diameter of carbon nanotube (CNT) as well as CNT weight fraction on the uniaxial stress-strain behavior, stiffness, and strength of CNT-reinforced epoxy-matrix composites. The experimental results show that average Young's moduli of 5 wt%-CNT/epoxy composites with a CNT diameterD<20 nm andD=40∼60 nm are 4.56 GPa and 4.36 GPa, and the average tensile strengths are 52.89 MPa and 46.80 MPa, respectively, which corresponds to a percentage increase of 61.1%, 54.1%, 106%, and 82.3%, respectively. Two micromechanics models are employed and the predicted Young's moduli are benchmarked with the experimental data of MWCNT-reinforced epoxy-matrix composites.

Elastomer Behavior IV. Loop Structure of Elastomer Networks

1966 ◽  
Vol 39 (5) ◽  
pp. 1489-1495
Author(s):  
L. C. Case ◽  
R. V. Wargin
Keyword(s):  
Experimental Data ◽  
Crosslink Density ◽  
Strain Curve ◽  
Uniaxial Stress ◽  
Polymer Chains ◽  
Theoretical Treatment ◽  
Loop Structure ◽  
Stress Strain ◽  
Strain Behavior ◽  
Selection Of

Abstract A new theoretical treatment strongly indicates that an elastomer network actually consists of a system of fused, closed, interpenetrating loops of polymer chains. This interpenetrating loop structure restricts the movement of the chains and thereby affects the stress-strain behavior of the elastomer. Methods have been developed to enable the calculation of the number of effective crosslinks caused by loop interpenetrations (virtual crosslinks). The uniaxial stress-strain behavior of an elastomer predicted using our methods can be fitted almost perfectly to published experimental data by proper selection of chain parameters. Previous theoretical treatments gave only a qualitative fit to the experimental data for the stress-strain behavior of elastomers and were not capable of predicting the correct shape of the experimental stress-strain curve. The present treatment gives a nearly perfect fit for both stress as a function of strain at constant crosslink density, and stress as a function of crosslink density at constant strain, and thus represents a vast improvement.

Tensile Properties of Epoxy Composites Reinforced with Continuous Sisal Fibers

2014 ◽  
Vol 775-776 ◽  
pp. 284-289 ◽  
Author(s):  
Sergio Neves Monteiro ◽  
Frederico Muylaert Margem ◽  
Wellington Pereira Inácio ◽  
Artur Camposo Pereira ◽  
Michel Picanço Oliveira
Keyword(s):  
Mechanical Properties ◽  
Tensile Properties ◽  
Epoxy Matrix ◽  
Room Temperature ◽  
Fracture Analysis ◽  
Epoxy Composites ◽  
Matrix Composites ◽  
Matrix Interface ◽  
Fiber Matrix Interface ◽  
Sisal Fibers

The tensile properties of DGEBA/TETA epoxy matrix composites reinforced with different amounts of sisal fibers were evaluated. Composites reinforce with up to 30% in volume of long, continuous and aligned sisal fibers were room temperature tested in an Instron machine. The fracture was analyzed by SEM. The results showed significant changes in the mechanical properties with the amount of sisal fibers. These mechanical properties were compared with other bend-tested composites results. The fracture analysis revealed a weak fiber/matrix interface, which could be responsible for the performance of some properties.

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