scholarly journals Development of aeronautical epoxy nanocomposites having an integrated selfhealing ability

2018 ◽  
Vol 233 ◽  
pp. 00021 ◽  
Author(s):  
Liberata Guadagno ◽  
Luigi Vertuccio ◽  
Carlo Naddeo ◽  
Elisa Calabrese ◽  
Giuseppina Barra ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Barbituric Acid ◽  
Mechanical Analysis ◽  
Self Healing ◽  
Multi Wall Carbon Nanotubes ◽  
Healing Efficiency ◽  
Donor And Acceptor ◽  
Rubber Toughened ◽  
Hydrogen Bondings ◽  
Functionalized Mwcnts

Functionalized multi-wall carbon nanotubes (MWCNTs) have been embedded in a rubber-toughened epoxy formulation in order to explore the possibility to impart an auto-repair function to the epoxy matrix. The nanofiller has been covalently functionalized with hydrogen bonding moieties able to act as donor and acceptor of hydrogen bondings. Healing efficiencies have been evaluated for nano charged epoxy formulations at a loading of 0.5% wt/wt of functionalized MWCNTs bearing barbituric acid and thymine-based ligands. For both the performed functionalizations, a self-healing efficiency higher than 50% has been found. Dynamic Mechanical Analysis (DMA) highlights that the inclusion of nanofiller increases the storage moduli. Furthermore, DMA analysis evidences the presence of a phase characterized by a greater mobility of the epoxy chains, which promotes the activation of self-healing mechanisms.

scholarly journals Self-Healing Photocurable Epoxy/thiol-ene Systems Using an Aromatic Epoxy Resin

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Ricardo Acosta Ortiz ◽  
Omar Acosta Berlanga ◽  
Aída Esmeralda García Valdez ◽  
Rafael Aguirre Flores ◽  
José Guadalupe Télles Padilla ◽  
...  
Keyword(s):  
Disulfide Bonds ◽  
Epoxy Resins ◽  
Room Temperature ◽  
Gel Permeation Chromatography ◽  
Mechanical Analysis ◽  
Hypervalent Iodine ◽  
Self Healing ◽  
Healing Efficiency ◽  
Kinetics Of ◽  
Epoxy Groups

A rapid and efficient method to obtain self-healing epoxy resins is discussed. This method is based on the use of a thiol-disulfide oligomer obtained by partial oxidation of a multifunctional thiol using a hypervalent iodine (III) compound as oxidant. The oligomer was characterized by Fourier transform infrared spectroscopy (FTIR), Raman and nuclear magnetic resonance spectroscopies, and gel permeation chromatography (GPC). The oligomer was a joint component of the thiol-ene system along with a tetra-allyl-functionalized curing agent. The kinetics of the photopolymerization of diglycidylether of bisphenol A (DGEBA) revealed that conversions of the epoxy groups as high as 80% were achieved in only 15 minutes by increasing the concentration of the thiol-ene system in the formulation. The disulfide bonds introduced in the copolymer using the thiol-disulfide oligomer allowed the repairing of the test specimens in as little as 10 minutes when the specimens were heated at 80°C or for 500 minutes at room temperature. The analysis of the mechanical properties using dynamic mechanical analysis (DMA) showed that the specimens displayed a healing efficiency up to 111% compared with the unhealed specimens, depending on the amount of polythioethers present in the copolymer.

Microcapsules Containing Solvent and Epoxy With Multi-Walled Carbon Nanotubes for Self-Healing

2014 ◽  
Author(s):  
Paul Phamduy ◽  
Byungki Kim
Keyword(s):  
Carbon Nanotubes ◽  
In Situ Polymerization ◽  
Phenyl Acetate ◽  
Self Healing ◽  
Test Fixture ◽  
Healing Efficiency ◽  
Multi Walled Carbon Nanotubes ◽  
Three Point Bend Test ◽  
Point Bend ◽  
Walled Carbon Nanotubes

Microcapsules containing epoxy resin EPON 862, phenyl acetate solvent, and multi-walled carbon nanotubes were fabricated by in-situ polymerization for the development of a self-healing composite. The microcapsules were embedded in an epoxy matrix in single-edged notch bend shapes for fracture testing on a three-point bend test fixture. Healing efficiency was calculated for specimens with various microcapsule loading ratios. Fracture tests confirmed healing ability with the microcapsules. Preliminary results indicated higher healing efficiencies with increased microcapsule loading.

scholarly journals Self-Healing and Mechanical Properties of Thermoplastic Polyurethane/Eugenol-Based Phenoxy Resin Blends via Exchange Reactions

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1011 ◽  
Author(s):  
Jing-Yu Liang ◽  
Se-Ra Shin ◽  
Soo-Hyoung Lee ◽  
Dai-Soo Lee
Keyword(s):  
Mechanical Properties ◽  
Exchange Reaction ◽  
Thermoplastic Polyurethane ◽  
Mechanical Analysis ◽  
Resin Content ◽  
Self Healing ◽  
Exchange Reactions ◽  
Scanning Calorimetry ◽  
Healing Efficiency ◽  
Different Types

The possibility of exchange reactions and thermal self-healing in blends of thermoplastic polyurethane (TPU) and phenoxy resin was investigated herein. The analyses were based on characterization obtained via differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), dynamic mechanical analysis (DMA), and tensile test. A new phenoxy resin was synthesized from eugenol, and blends with different types of TPU were prepared to investigate the exchange reaction, thermal self-healing, and mechanical properties. The influence of phenoxy resin content on the mechanical behavior and healing efficiency was studied. Improvement of storage modulus owing to the increase of phenoxy resin content was observed. Results suggest that the exchange reaction between phenoxy- and ester-type TPU occurred during thermal treatment. However, little exchange occurred between phenoxy resin and ether-type TPU. Specifically, only ester-type TPU exhibited a significant exchange reaction in the phenoxy resin blend. Furthermore, in the presence of a catalyst (e.g., zinc acetate), the exchange reaction readily occurred, and the healing efficiency improved by the addition of the catalyst and increase in the phenoxy content.

scholarly journals Tunneling Atomic Force Microscopy Analysis of Supramolecular Self-Responsive Nanocomposites

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1401
Author(s):  
Marialuigia Raimondo ◽  
Elisa Calabrese ◽  
Wolfgang H. Binder ◽  
Philipp Michael ◽  
Sravendra Rana ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Hydrogen Bonding ◽  
Self Healing ◽  
Advanced Technique ◽  
Multi Wall Carbon Nanotubes ◽  
Intrinsic Nature ◽  
Force Microscopy ◽  
Atomic Force ◽  
Donor And Acceptor ◽  
Covalently Linked

A big step forward for composite application in the sector of structural materials is given by the use of Multi-Wall Carbon Nanotubes (MWCNTs) functionalized with hydrogen bonding moieties, such as barbiturate and thymine, to activate self-healing mechanisms and integrate additional functionalities. These materials with multiple healing properties at the same damaged site, imparted by hydrogen bonds, will also have the potential to improve material reliability, extend the service life, reduce replacement costs, and improve product safety. This revolutionary approach is obtained by integrating the non-covalent interactions coupled with the conventional covalent approach used to cross-link the polymer. The objective of this work is to characterize rubber-toughened supramolecular self-healing epoxy formulations based on unfunctionalized and functionalized MWCNTs using Tunneling Atomic Force Microscopy (TUNA). This advanced technique clearly shows the effect produced by the hydrogen bonding moieties acting as reversible healing elements by their simultaneous donor and acceptor character, and covalently linked to MWCNTs to originate self-healing nanocomposites. In particular, TUNA proved to be very effective for the morphology study of both the unfunctionalized and functionalized carbon nanotube-based conductive networks, thus providing useful insights aimed at understanding the influence of the intrinsic nature of the nanocharge on the final properties of the multifunctional composites.

Electrical, thermal and thermo-mechanical properties of epoxy/multi-wall carbon nanotubes/mineral fillers nanocomposites

2018 ◽  
Vol 52 (23) ◽  
pp. 3209-3217 ◽  
Author(s):  
Eduardo H Backes ◽  
Fabio R Passador ◽  
Christian Leopold ◽  
Bodo Fiedler ◽  
Luiz A Pessan
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Calcium Carbonate ◽  
In Situ Polymerization ◽  
Mechanical Analysis ◽  
Multi Wall Carbon Nanotubes ◽  
Aspect Ratios ◽  
Tan Δ ◽  
Mineral Fillers

Epoxy/multi-wall carbon nanotubes and epoxy/multi-wall carbon nanotubes/mineral fillers nanocomposites were produced via in situ polymerization assisted by three-roll-milling. Epoxy/multi-wall carbon nanotubes nanocomposites presented very low electrical percolation threshold, near to 0.05 wt %. In this study, we used different mineral fillers, with different aspect ratios: calcium carbonate, montmorillonite, and sepiolite. We evaluated the effect of the addition of these fillers on electrical, thermal, and thermo-mechanical properties of epoxy/multi-wall carbon nanotubes nanocomposites. The addition of calcium carbonate in epoxy/multi-wall carbon nanotubes nanocomposites increased the electrical conductivity of this nanocomposite, due to volume exclusion effect. The addition of sepiolite decreased the loss factor and improved electrical constant, however, reduced the electrical conductivity in these nanocomposites, when compared to epoxy/multi-wall carbon nanotubes. Regarding thermal properties, no significant change in glass transition was observed. Thermo-mechanical analysis for nanocomposites showed slight changes in tan (δ) and storage modulus, which is related to the interaction between epoxy, multi-wall carbon nanotubes and mineral fillers.

Incorporation of Multi Wall Carbon Nanotubes into Glass-Surfaces via Laser-Treatment

2003 ◽  
Vol 772 ◽  
Author(s):  
T. Seeger ◽  
G. de la Fuente ◽  
W.K. Maser ◽  
A.M. Benito ◽  
A. Righi ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Continuous Wave ◽  
Silica Surface ◽  
Multi Wall Carbon Nanotubes ◽  
Composite Formation ◽  
Multi Walled Carbon Nanotubes ◽  
Glass Surfaces ◽  
Walled Carbon Nanotubes ◽  
First Time ◽  
Scanning Electron

AbstractCarbon nanotubes (CNT) are interesting candidates for the reinforcement in robust composites and for conducting fillers in polymers due to their fascinating electronic and mechanical properties. For the first time, we report the incorporation of multi walled carbon nanotubes (MWNTs) into silica-glass surfaces by means of partial surface-melting caused by a continuous wave Nd:YAG laser. MWNTs were detected being well incorporated in the silica-surface. The composites are characterized using scanning electron microscopy (SEM) and Raman-spectroscopy. A model for the composite-formation is proposed based on heatabsorption by MWNTs and a partial melting of the silica-surface.

Study of Fibroblast and Platelet Adhesion on Multi-wall Carbon Nanotubes

2011 ◽  
Vol 26 (1) ◽  
pp. 73-77 ◽  
Author(s):  
Meng-Li ZHAO ◽  
Yu-Chen YUE ◽  
Li YUAN ◽  
De-Jun LI ◽  
Xiao-Ying LÜ ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Platelet Adhesion ◽  
Multi Wall Carbon Nanotubes

Transient Free Convective Flow of CNT Water Nanofluid with Heat Transfer from a Moving Cylinder

2020 ◽  
Vol 10 ◽  
Author(s):  
C. Sridevi ◽  
A. Sailakumari
Keyword(s):  
Carbon Nanotubes ◽  
Heat Generation ◽  
Convective Flow ◽  
Volume Fraction ◽  
Vertical Cylinder ◽  
Single Wall Carbon Nanotubes ◽  
Free Convective Flow ◽  
Multi Wall Carbon Nanotubes ◽  
Moving Cylinder ◽  
Variable Surface

Background: In this paper, transient two-dimensional laminar boundary layer viscous incompressible free convective flow of water based nanofluid with carbon nanotubes (CNTs) past a moving vertical cylinder with variable surface temperature is studied numerically in the presence of thermal radiation and heat generation. Methods: The prevailing partial differential equations which model the flow with initial and boundary conditions are solved by implicit finite difference method of Crank Nicolson type which is unconditionally stable and convergent. Results: Influence of Grashof number (Gr), nanoparticle volume fraction ( ), heat generation parameter (Q), temperature exponent (m), radiation parameter (N) and time (t) on velocity and temperature profiles are sketched graphically and elaborated comprehensively. Conclusion: Analysis of Nusselt number and Skin friction coefficient are also discussed numerically for both single wall carbon nanotubes (SWCNTs) and multi wall carbon nanotubes (MWCNTs).

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