scholarly journals Multifunctional Thermally Remendable Nanocomposites

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Edward D. Sosa ◽  
Thomas K. Darlington ◽  
Brian A. Hanos ◽  
Mary Jane E. O’Rourke

Challenges associated with damage tolerance in polymer matrix composites must be successfully addressed in order to ensure highly reliable structures with significant weight savings. Self-healing materials provide a viable means to surmount damage tolerance concerns, thereby allowing for the realization of the mass reduction such structures have promised but not yet achieved. Introduction of multifunctional properties into self-healing composites can further extend their usefulness. This study examines the incorporation of carbon nanotubes into a self-healing composite in order to achieve this. Composite panels were fabricated with carbon fibers, a bismaleimide tetrafuran (2MEP4F) polymer resin, and various carbon nanotube materials. The composites exhibit enhancement in electrical, mechanical, and thermal properties. The healing mechanism is a thermally activated reversible polymerization of the 2MEP4F resin. The proposed method of heating exploits the enhanced microwave absorption inherent to carbon nanotubes to provide the thermal energy required for the reversible polymerization. Microwave testing demonstrated that the heating efficiency is increased, allowing uniform heating to the required temperature for polymer healing. Impacted composites show localized heating at the damage site, which implies that microwave heating can also be used as a means for damage detection and potential structural health monitoring.

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 201
Author(s):  
Stefano Paolillo ◽  
Ranjita K. Bose ◽  
Marianella Hernández Santana ◽  
Antonio M. Grande

This article reviews some of the intrinsic self-healing epoxy materials that have been investigated throughout the course of the last twenty years. Emphasis is placed on those formulations suitable for the design of high-performance composites to be employed in the aerospace field. A brief introduction is given on the advantages of intrinsic self-healing polymers over extrinsic counterparts and of epoxies over other thermosetting systems. After a general description of the testing procedures adopted for the evaluation of the healing efficiency and the required features for a smooth implementation of such materials in the industry, different self-healing mechanisms, arising from either physical or chemical interactions, are detailed. The presented formulations are critically reviewed, comparing major strengths and weaknesses of their healing mechanisms, underlining the inherent structural polymer properties that may affect the healing phenomena. As many self-healing chemistries already provide the fundamental aspects for recyclability and reprocessability of thermosets, which have been historically thought as a critical issue, perspective trends of a circular economy for self-healing polymers are discussed along with their possible advances and challenges. This may open up the opportunity for a totally reconfigured landscape in composite manufacturing, with the net benefits of overall cost reduction and less waste. Some general drawbacks are also laid out along with some potential countermeasures to overcome or limit their impact. Finally, present and future applications in the aviation and space fields are portrayed.


2021 ◽  
pp. 002199832098764
Author(s):  
Mingren Jiang ◽  
Xianhua Cheng

Rare earth modified acidified carbon nanotubes were prepared by functionalization of acidified carbon nanotubes with different concentrations of LaCl3. The modification results were characterized by Fourier-transform infrared and X-ray photoelectron spectroscopy. The rare earth successfully increases the surface activity of the acidified carbon nanotubes. Polymer matrix composites were prepared by using the rare earth modified acidified carbon nanotubes as the reinforcement in epoxy matrix. Mechanical properties were analyzed by Zwick Z100 testing machine and the tribological behaviors were test by multifunctional tribological tester. Compared with pure epoxy (epoxy resin), the mechanical strength of the best composite sample was increased by 50–120%, the coefficient of friction was reduced by 19.4% and the wear rate was reduced by approximately 40 times. The experimental results show that the RE concentration of 0.2–0.3 wt% has the most obvious influence on the properties of polymer composites. The mechanism of rare earth reinforcement in polymer matrix is analyzed and suggested.


1999 ◽  
Vol 121 (4) ◽  
pp. 524-529
Author(s):  
Ozgur Turkgenc ◽  
Reza Dianati ◽  
Milan Mitrovic ◽  
H. Thomas Hahn ◽  
Peter Shyprykevich

Much research has been conducted to understand the damage tolerance behavior of polymer matrix composites, but there are so many parameters involved that the development of a generic model is rather difficult. The present paper proposes an information system, which can overcome such difficulty. In this system, a list of possible parameters is generated and used as input. The output contains compression strength after impact, dent depth and damage area as well as pertinent reference information. The information system is constituted in a relational database environment and tools from expert system technology are incorporated. Case examples are included to demonstrate the practical use of the software for both data retrieval and similarity studies.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Yuli Chen ◽  
Shengtao Wang ◽  
Fei Pan ◽  
Jianyu Zhang

The electrical percolation of polymer-matrix composites (PMCs) containing hybrid fillers of carbon nanotubes (CNTs) and carbon black (CB) is estimated by studying the connection possibility of the fillers using Monte Carlo simulation. The 3D simulation model of CB-CNT hybrid filler is established, in which CNTs are modeled by slender capped cylinders and CB groups are modeled by hypothetical spheres with interspaces because CB particles are always agglomerated. The observation on the effects of CB and CNT volume fractions and dimensions on the electrical percolation threshold of hybrid filled composites is then carried out. It is found that the composite electrical percolation threshold can be reduced by increasing CNT aspect ratio, as well as increasing the diameter ratio of CB groups to CNTs. And adding CB into CNT composites can decrease the CNT volume needed to convert the composite conductivity, especially when the CNT volume fraction is close to the threshold of PMCs with only CNT filler. Different from previous linear assumption, the nonlinear relation between CB and CNT volume fractions at composite percolation threshold is revealed, which is consistent with the synergistic effect observed in experiments. Based on the nonlinear relation, the estimating equation for the electrical percolation threshold of the PMCs containing CB-CNT hybrid fillers is established.


2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Wei Wang ◽  
Yuhe Zhu ◽  
Susan Liao ◽  
Jiajia Li

This review paper reported carbon nanotubes reinforced composites for biomedical applications. Several studies have found enhancement in the mechanical properties of CNTs-based reinforced composites by the addition of CNTs. CNTs reinforced composites have been intensively investigated for many aspects of life, especially being made for biomedical applications. The review introduced fabrication of CNTs reinforced composites (CNTs reinforced metal matrix composites, CNTs reinforced polymer matrix composites, and CNTs reinforced ceramic matrix composites), their mechanical properties, cell experimentsin vitro, and biocompatibility testsin vivo.


Author(s):  
A. Krzyżak ◽  
E. Kosicka ◽  
R. Szczepaniak ◽  
T. Szymczak

Purpose: Carbon nanotubes are used in composite materials due to the improvement of (including tribological) properties of composites, especially thermoplastic matrix composites. This demonstrates the potential of CNTs and the validity of research on determining the impact of this type of reinforcement on the composite materials under development. Design/methodology/approach: The article presents selected results of research on polymer composites made of C.E.S. R70 resin, C.E.S. H72 hardener with the addition of a physical friction modifier (CNTs) with a percentage by volume of 18.16% and 24.42%, respectively, which also acts as a reinforcement. The produced material was subjected to hardness measurements according to the Shore method and EDS analysis. The study of abrasive wear in reciprocating movement was carried out using the Taber Linear Abraser model 5750 tribotester and a precision weight. The surface topography of the composite material after tribological tests was determined using scanning electron microscopy (SEM). Some of the mentioned tests were carried out on samples made only of resin, used as the matrix of the tested polymer composite. Findings: Carbon nanotubes used in polymer matrix composites, including bisphenol A/F epoxy resin have an influence on the tribological properties of the material. The addition of carbon nanotubes contributed to a 24% increase in the Ra parameter relative to pure resin, to a level corresponding to rough grinding of steel. Research limitations/implications: The results of the tests indicate the need to continue research in order to optimize the composition of composites in terms of operating parameters of friction nodes in broadly understood aviation. Originality/value: The analysed literature did not find any studies on the impact of the addition of carbon nanotubes on epoxy resins based on bisphenol A/F. Due to the wide scope of application of such resins, the properties of such composite materials in which carbon nanotubes are the reinforcing phase have been investigated.


2018 ◽  
Vol 48 (1) ◽  
pp. 83-106
Author(s):  
Sławomir Augustyn ◽  
Rafał Kowalski

Abstract This publication presented the main issues related to fatigue of polymer composite materials. It was featured a fatigue stress test based on composite sample, made of carbon fiber-reinforced polymer, using the four-point bending method. The test was carried out with the initial load and using positive load cycles. The perspectives of diagnostics and self-healing of composite materials, including intelligent materials, were also presented.


2008 ◽  
Vol 606 ◽  
pp. 61-77 ◽  
Author(s):  
Johann Cho ◽  
Aldo Roberto Boccaccini

Carbon nanotubes (CNTs) are promising reinforcing elements for structural composites due to their remarkable mechanical properties. The impressive electrical and thermal properties of this new form of carbon also make CNTs containing composites ideal candidates for multifunctional applications. In the past decade, researchers have investigated CNTs as toughening inclusions to overcome the intrinsic brittleness of ceramics and glasses. Although there are numerous investigations available in the literature, a significant progress has not occurred or it has been rather slow compared to advances in the field of CNT/polymer matrix composites. This paper reviews current trends in research and development efforts on the use of CNTs for fabrication of ceramic and glass matrix composite materials. The review includes a summary of key issues related to the optimisation of CNT-based composites and an overview of investigations dealing with processing techniques developed to optimise dispersion quality, interfaces and density. The mechanical properties of as-produced composites are discussed and a comprehensive comparison of data available for different matrix materials is presented. Finally, the potential applications of the resulting CNT/inorganic matrix composites and the scope for future developments in the field are highlighted.


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