scholarly journals Simultaneous Recovery of Matrix and Fiber in Carbon Reinforced Composites through a Diels–Alder Solvolysis Process

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1007 ◽  
Author(s):  
Giovanni Fortunato ◽  
Luca Anghileri ◽  
Gianmarco Griffini ◽  
Stefano Turri
Keyword(s):  
Polymer Network ◽  
Fiber Composites ◽  
Diels Alder ◽  
Carbon Fiber Composites ◽  
Reinforced Composites ◽  
New Approach ◽  
Thermoset Composites ◽  
The Matrix ◽  
Thermal Reversibility ◽  
Very High

Efficient and comprehensive recycling of fiber-reinforced thermosets is particularly challenging, since the irreversible degradation of the matrix component is necessary in order to separate the fiber component in high purity. In this work, a new approach to fully recyclable thermoset composites is presented, based on the thermal reversibility of an epoxy-based polymer network, crosslinked through Diels–Alder (DA) chemistry. Carbon fiber composites, fabricated by compression molding, were efficiently recycled through a simple solvolysis procedure in common solvents, under mild conditions, with no catalysts. Specifically, the purity of reclaimed fibers, assessed by thermogravimetric analysis and scanning electron microscopy, was very high (>95%) and allowed successful reprocessing into second generation composites. Moreover, the dissolved matrix residues were directly employed to prepare smart, thermally healable coatings. Overall, DA chemistry has been shown to provide a convenient strategy towards circular economy of thermoset composites.

Bending properties of carbon fiber nanocomposites with lamination structure of reinforcement

2016 ◽  
Vol 36 (5) ◽  
pp. 481-487 ◽  
Author(s):  
Jun Hee Song
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Fiber Composites ◽  
Advanced Materials ◽  
Carbon Fiber Composites ◽  
Reinforced Composites ◽  
Bending Tests ◽  
Reinforced Plastics ◽  
Composite Samples ◽  
Vartm Process

Abstract Advanced materials with excellent performance are in high demand in modern industry. Carbon fiber composites offer a number of advantageous mechanical properties. A significant improvement in fiber-reinforced composites can be achieved by dispersing a very small amount of nanofiller in the resin. Vacuum-assisted resin transfer molding (VARTM) is one of the most important processes for producing reinforced plastics. In this work, several composite samples were fabricated with the infusion of carbon nanofibers (CNFs) into the epoxy matrix using VARTM process. Using scanning electron microscopy (SEM), it was confirmed that CNFs were well dispersed in the resin. Bending tests were performed to investigate the mechanical properties of the samples, and SEM, to examine the fracture surfaces.

Determination of Flexible Interlayer Thickness for Fiber Reinforced Composites

1989 ◽  
Vol 170 ◽  
Author(s):  
King H. Lo ◽  
Robert W. Schmitz ◽  
William G. Gottenberg
Keyword(s):  
Fiber Composites ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Stress Distributions ◽  
Interlayer Thickness ◽  
Fiber Reinforced ◽  
The Matrix ◽  
Composite Cylinders ◽  
Selection Of

AbstractThe influence of flexible interlayers/interphases on the performance of unidirectional fiber reinforced composites is studied. Micromechanical analysis based on the embedded composite cylinders model is used to study the stiffness as well as the internal stress distributions within the matrix phase of composites. Based on the results of the analysis, a criterion is proposed for the selection of optimal interlayer thickness for fiber composites. The proposed criterion gives results which seem to correlate well with the experimental data published in the literature.

The Effect of Debonding Angle on the Reduction of Effective Moduli of Particle and Fiber-Reinforced Composites

2002 ◽  
Vol 69 (3) ◽  
pp. 292-302 ◽  
Author(s):  
Y. H. Zhao ◽  
G. J. Weng
Keyword(s):  
Transversely Isotropic ◽  
Fiber Composites ◽  
Fiber Reinforced Composites ◽  
Anisotropic Damage ◽  
Reinforced Composites ◽  
Effective Moduli ◽  
Loading Mode ◽  
Interfacial Cracks ◽  
The Matrix ◽  
Composite Stiffness

In an effort to uncover the effect of interfacial partial debonding on the reduction of composite stiffness, a reduced moduli approach is proposed for the fictitious inclusions which are used to replace the original partially debonded inclusions. The fictitious inclusions are now perfectly bonded to the matrix and any micromechanical theory can be called upon to estimate the moduli of the composite. Using the volume of the inclusion directly beneath the interfacial cracks under the considered loading mode as a measure of damage, a set of anisotropic damage parameters is established in terms of the debonding angle, providing the reduced moduli for the fictitious inclusions. Specific considerations include debonding on the top and bottom of spheres and prolate inclusions, debonding on the lateral surface of spheres and oblate inclusions, and debonding on the top and bottom of circular fibers and elliptic cylinders. The reductions of the five transversely isotropic moduli for the partially debonded particle composites and the nine orthotropic moduli for the partially debonded fiber composites are examined as the debonding angle increases. The theory is also compared with some finite element results, and it suggests that the concept proposed to estimate the reduced moduli of the fictitious inclusions is a viable one.

Electromechanical study of carbon fiber composites

1998 ◽  
Vol 13 (11) ◽  
pp. 3081-3092 ◽  
Author(s):  
Xiaojun Wang ◽  
Xuli Fu ◽  
D. D. L. Chung
Keyword(s):  
Carbon Fiber ◽  
Electrical Resistance ◽  
Fiber Composites ◽  
Single Fiber ◽  
Fiber Direction ◽  
Carbon Fiber Composites ◽  
Fiber Waviness ◽  
Pull Out ◽  
The Matrix ◽  
Fiber Matrix

Electromechanical testing involving simultaneous electrical and mechanical measurements under load was used to study the fiber-matrix interface, the fiber residual compressive stress, and the degree of marcelling (fiber waviness) in carbon fiber composites. The interface study involved single fiber pull-out testing while the fiber-matrix contact electrical resistivity was measured. The residual stress study involved measuring the electrical resistance of a single fiber embedded in the matrix while the fiber was subjected to tension through its exposed ends. The marcelling study involved measuring the electrical resistance of a composite in the through-thickness direction while tension within the elastic regime was applied in the fiber direction.

scholarly journals Carbon Nanotube Layer for Reduction of Fiber Print-Through in Carbon Fiber Composites

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Joana F. Guedes ◽  
Marta S. S. Martins ◽  
Ramiro Martins ◽  
Nuno Rocha
Keyword(s):  
Carbon Nanotube ◽  
Carbon Fiber ◽  
Production Method ◽  
Fiber Composites ◽  
Fiber Reinforced Composites ◽  
Carbon Fiber Composites ◽  
Reinforced Composites ◽  
Space Applications ◽  
Scanning Electron Microscopy Morphology ◽  
Carbon Fiber Reinforced Composites

Fiber print-through effect is a limitation to the use of carbon fiber-reinforced composites in space applications, namely, mirror telescopes. Replica method is used for the production of lightweight telescope mirrors. However, this method requires a polished mandrel, increasing considerably the final cost. In this work, we report a cheaper and simpler alternative production method, which consists in the addition of a carbon nanotube filled epoxy resin layer on the surface of carbon reinforced composites, in order to reduce fiber print-through of the materials. The influence of different carbon nanotube functionalizations, concentrations, and dispersion levels are also assessed. The surface properties are evaluated by interferometry (roughness and waviness) and scanning electron microscopy (morphology). The results show that the waviness, roughness, and consequently fiber print-though are considerably reduced with the addition of a thin layer of nonfunctionalized carbon nanotubes.

Electromechanical Study of Carbon Fiber Composites

1997 ◽  
Vol 500 ◽  
Author(s):  
Xiaojun Wang ◽  
Xuli Fu ◽  
D.D.L. Chung
Keyword(s):  
Residual Stress ◽  
Carbon Fiber ◽  
Fiber Composites ◽  
Single Fiber ◽  
Fiber Direction ◽  
Carbon Fiber Composites ◽  
Fiber Waviness ◽  
Pull Out ◽  
The Matrix ◽  
Fiber Matrix

ABSTRACTElectromechanical testing involving simultaneous electrical and mechanical measurements under load was used to study the fiber-matrix interface, fiber residual stress and marcelling (fiber waviness) in carbon fiber composites. The interface study involved single fiber pull-out while the fiber-matrix contact resistivity was measured. The residual stress study involved measuring the resistance of a single fiber embedded in the matrix while the fiber was tensioned at its exposed ends. The marcelling study involved measuring the resistance of a composite in the through-thickness direction while tension was applied in the fiber direction.

Dislocation structures around SiO2 Particles in aged Cu-Cr-SiO2

1978 ◽  
Vol 36 (1) ◽  
pp. 594-595
Author(s):  
N.J. Long ◽  
M.H. Loretto ◽  
C.H. Lloyd
Keyword(s):  
Flow Stress ◽  
Single Crystals ◽  
Room Temperature ◽  
Thin Foil ◽  
Age Hardening ◽  
Dispersion Strengthening ◽  
Accurate Picture ◽  
The Matrix ◽  
Very High ◽  
Good Agreement

IntroductionThere have been several t.e.m. studies (1,2,3,4) of the dislocation arrangements in the matrix and around the particles in dispersion strengthened single crystals deformed in single slip. Good agreement has been obtained in general between the observed structures and the various theories for the flow stress and work hardening of this class of alloy. There has been though some difficulty in obtaining an accurate picture of these arrangements in the case when the obstacles are large (of the order of several 1000's Å). This is due to both the physical loss of dislocations from the thin foil in its preparation and to rearrangement of the structure on unloading and standing at room temperature under the influence of the very high localised stresses in the vicinity of the particles (2,3).This contribution presents part of a study of the Cu-Cr-SiO2 system where age hardening from the Cu-Cr and dispersion strengthening from Cu-Sio2 is combined.

Phase identification in SiC whisker reinforced Al2O3-R2O3-based composites

1992 ◽  
Vol 50 (1) ◽  
pp. 152-153
Author(s):  
C.M. Sung ◽  
K.J. Ostreicher ◽  
M.L. Huckabee ◽  
S.T. Buljan
Keyword(s):  
Analytical Electron Microscopy ◽  
Phase Identification ◽  
Reinforced Composites ◽  
Ion Milling ◽  
X Ray ◽  
Binary Oxides ◽  
Analytical Electron ◽  
The Matrix ◽  
Second Phases ◽  
Convergent Beam

A series of binary oxides and SiC whisker reinforced composites both having a matrix composed of an α-(Al, R)2O3 solid solution (R: rare earth) have been studied by analytical electron microscopy (AEM). The mechanical properties of the composites as well as crystal structure, composition, and defects of both second phases and the matrix were investigated. The formation of various second phases, e.g. garnet, β-Alumina, or perovskite structures in the binary Al2O3-R2O3 and the ternary Al2O3-R2O3-SiC(w) systems are discussed.Sections of the materials having thicknesses of 100 μm - 300 μm were first diamond core drilled. The discs were then polished and dimpled. The final step was ion milling with Ar+ until breakthrough occurred. Samples prepared in this manner were then analyzed using the Philips EM400T AEM. The low-Z energy dispersive X-ray spectroscopy (EDXS) data were obtained and correlated with convergent beam electron diffraction (CBED) patterns to identify phase compositions and structures. The following EDXS parameters were maintained in the analyzed areas: accelerating voltage of 120 keV, sample tilt of 12° and 20% dead time.

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