Melt-Quench Formed Smectic Phase in iPP/CNT Nanocomposites and its Re-Crystallization

2011 ◽  
Vol 1312 ◽  
Author(s):  
Georgi Georgiev ◽  
Yaniel Cabrera ◽  
Lauren Wielgus ◽  
Scott Schoen ◽  
Devin Ivy ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Liquid Crystalline ◽  
Isopropyl Alcohol ◽  
Model Systems ◽  
Commercial Application ◽  
Scanning Calorimetry ◽  
Smectic Liquid Crystal ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
The Impact

ABSTRACTThe largest commercial application of carbon nanotubes (CNT) are their polymer nanocomposites (PNCs). This motivates detailed studies of the interactions between CNTs and polymers and the ways the CNTs influence the crystallization behavior and structure of PNCs. We have chosen isotactic polypropylene (iPP) as one of the best model systems because of its ability to form a smectic liquid crystal phase. We studied iPP/CNT nanocomposites with CNT concentrations ranging from 0.01 to 5% per weight. We prepared films by compression molding and quenching in a mixture of isopropyl alcohol and dry ice. Some of the formed smectic liquid crystalline (LC) phase of iPP/CNT PNCs persisted to temperatures higher than the last melting temperature for iPP crystals. By means of differential scanning calorimetry we corroborated the existence of the LC phase in the nanocomposites and studied the impact of multi-walled carbon nanotubes on its melting and re-crystallization. We used a polarizing optical microscopy to reconfirm our DSC data.

Cure and Dynamic-Mechanical Behaviors of Vinyl Ester Resinfilled with Multi-Walled Carbon Nanotubes

2010 ◽  
Vol 150-151 ◽  
pp. 1413-1416 ◽  
Author(s):  
Hong Yan Chen ◽  
Zhen Xing Kong ◽  
Ji Hui Wang
Keyword(s):  
Carbon Nanotubes ◽  
Vinyl Ester ◽  
Mechanical Response ◽  
Cure Kinetics ◽  
Crosslinking Density ◽  
Vinyl Ester Resin ◽  
Scanning Calorimetry ◽  
Dynamic Mechanical ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

The cure kinetics of Derakane 411-350, a kind of vinyl ester resin, and its suspensions containing multi-walled carbon nanotubes( MWCNTs) were investigated via non-isothermal dynamic scanning calorimetry (DSC) measurements. The results showed that incorporation of MWCNTs into vinyl ester resin excessively reduces polymerization degree and crosslinking density of vinyl ester resin. For suppressing the negative effect caused by nanotubes, the higher temperature initiator combined with the initiator MEKP was used. Dynamic-mechanical Behavior testing was then carried out on the cured sample in order to relate the curing behavior of MWCNTs modified resin suspensions to mechanical response of their resulting nanocomposites. It was revealed that nanocomposites containing MWCNTs possessed larger storage modulus values as well as higher glass transition temperatures (Tg) as compared to those without MWCNTs after using mixed intiators system to improve the degree of cure.

scholarly journals Impact of Synthesis Parameters of Multi-Walled Carbon Nanotubes on their Thermoelectric Properties

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3567 ◽  
Author(s):  
Bogumiła Kumanek ◽  
Grzegorz Stando ◽  
Paweł S. Wróbel ◽  
Dawid Janas
Keyword(s):  
Carbon Nanotubes ◽  
Thermoelectric Properties ◽  
Synthesis Temperature ◽  
Injection Rate ◽  
Optimum Synthesis ◽  
Synthesis Parameters ◽  
Different Temperatures ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
The Impact

Carbon nanotubes have been intensively researched for many years because of a wide array of promising properties that they have. In this paper, we present the impact of synthesis parameters on thermoelectric properties of nanocarbon material. We conducted a number of syntheses of multi-walled carbon nanotubes (MWCNTs) at different temperatures (800 and 900 °C) using various amounts of catalyst (2%, 5.5%, and 9.6%) to facilitate the process. We also tested the influence of injection rate of precursor and the necessity of material purification on thermoelectric properties of MWCNTs. The electrical conductivity, thermal conductivity, and Seebeck coefficient were measurement for all samples. Based on these parameters, the values of Power Factor and Figure of Merit were calculated. The results show that the most important parameter in the context of thermoelectric properties is purity of employed MWCNTs. To obtain appropriate material for this purpose optimum synthesis temperature and appropriate content of the catalyst must be selected. The study also reveals that post-synthetic purification of nanocarbon is essential to produce an attractive material for thermoelectrics.

Compression Moulding of Thermoplastic Nanocomposites Filled with MWCNT

2017 ◽  
Vol 25 (8) ◽  
pp. 611-620 ◽  
Author(s):  
Fabrizio Quadrini ◽  
Denise Bellisario ◽  
Loredana Santo ◽  
Felicia Stan ◽  
Fetecau Catalin
Keyword(s):  
Carbon Nanotubes ◽  
Differential Scanning Calorimetry ◽  
Filler Content ◽  
Thermoplastic Polyurethane ◽  
Mechanical Tests ◽  
Compression Moulding ◽  
Scanning Calorimetry ◽  
Melt Mixing ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Multi-walled carbon-nanotubes (MWCNTs) were melt-mixed with three different thermoplastic matrices (polypropylene, PP, polycarbonate, PC, and thermoplastic polyurethane, TPU) to produce nanocomposites with three different filler contents (1, 3, and 5 wt.%). Initial nanocomposite blends (in the shape of pellets) were tested under differential scanning calorimetry to evaluate the effect of the melt mixing stage. Nanocomposite samples were produced by compression moulding in a laboratory-scale system, and were tested with quasi-static (bending, indentation), and dynamic mechanical tests as well as with friction tests. The results showed the effect of the filler content on the mechanical and functional properties of the nanocomposites. Compression moulding appeared to be a valuable solution to manufacture thermoplastic nanocomposites when injection moulding leads to loss of performance. MWCNT-filled thermoplastics could be used also for structural and functional uses despite, the present predominance of electrical applications.

scholarly journals Assessing the Damage Tolerance of Out of Autoclave Manufactured Carbon Fibre Reinforced Polymers Modified with Multi-Walled Carbon Nanotubes

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1080 ◽  
Author(s):  
Polyxeni Dimoka ◽  
Spyridon Psarras ◽  
Christine Kostagiannakopoulou ◽  
Vassilis Kostopoulos
Keyword(s):  
Carbon Nanotubes ◽  
Compressive Strength ◽  
Reference Material ◽  
Carbon Fibre ◽  
Damage Tolerance ◽  
Energy Levels ◽  
Multi Walled Carbon Nanotubes ◽  
Out Of Autoclave ◽  
Walled Carbon Nanotubes ◽  
The Impact

The present study aims to investigate the influence of multi-walled carbon nanotubes (MWCNTs) on the damage tolerance after impact (CAI) of the development of Out of Autoclave (OoA) carbon fibre reinforced polymer (CFRP) laminates. The introduction of MWCNTs into the structure of CFRPs has been succeeded by adding carbon nanotube-enriched sizing agent for the pre-treatment of the fibre preform and using an in-house developed methodology that can be easily scaled up. The modified CFRPs laminates with 1.5 wt.% MWCNTs were subjected to low velocity impact at three impact energy levels (8, 15 and 30 J) and directly compared with the unmodified laminates. In terms of the CFRPs impact performance, compressive strength of nanomodified composites was improved for all energy levels compared to the reference material. The test results obtained from C-scan analysis of nano-modified specimens showed that the delamination area after the impact is mainly reduced, without the degradation of compressive strength and stiffness, indicating a potential improvement of damage tolerance compared to the reference material. SEM analysis of fracture surfaces revealed the additional energy dissipation mechanisms; pulled-out carbon nanotubes which is the main reason for the improved damage tolerance of the multifunctional composites.

scholarly journals Electrically Conductive Composite based on Functionalized Carbon Nanotubes/Epoxy Resin

2020 ◽  
Vol 9 (4) ◽  
pp. 1401-1404
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Epoxy Resin ◽  
Isopropyl Alcohol ◽  
Electrophysical Properties ◽  
Electrically Conductive ◽  
Functionalized Carbon Nanotubes ◽  
Multi Walled Carbon Nanotubes ◽  
Electrically Conductive Composite ◽  
Walled Carbon Nanotubes

This work is devoted to the study of the effect of carbon nanotubes functionalization on the electrical conductivity of composite materials based on them. Carbon nanotubes were functionalized by treatment in nitric acid and isopropyl alcohol. Changes in the morphology of multi-walled carbon nanotubes during liquid-phase functionalization were investigated using Auger-electron microscopy. Samples of composite material on the basis of initial and functionalized carbon nanotubes and epoxy resin were prepared and the concentration dependence of electrical conductivity using the four-probe method was studied. The study reveals the effect of functionalization in various solutions on the electrophysical properties of the obtained carbon nanotubes/epoxy composites.

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