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

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.

Author(s):  
Dhiraj Kumar ◽  
Kalyan Kumar Singh

Laser machining of carbon fibre reinforced polymer composites is a challenging task due to a significant difference between physical and thermal properties of the constituent materials, i.e. polymer matrix and carbon fibres. This results in extended heat-affected zone (HAZ), taper kerf and poor surface finishing. This paper focuses on an investigation, attempting to minimise the divergence in the decomposition temperature of carbon fibres and epoxy resin by adding multi-walled carbon nanotubes in polymer matrix as a secondary reinforcement. High thermal conductivity of multi-walled carbon nanotubes increases the thermal diffusivity of polymer matrix, which in turn reduces the matrix recession. In addition, laser power and scan speed was also considered as an input parameter and their influence on output responses such as HAZ, taper angle and surface roughness has been studied. To analyse the effect of multi-walled carbon nanotubes on the resultant thermal damage, an innovative technique, i.e. scanning acoustic microscopy was used. This technique provides a ply-by-ply damage analysis. C-scans of the top and bottom surface of the machined holes in the composite were also carried out. Further, micrographs of the holes were taken to analyse the quality of the holes using field-emission scanning electron microscope. The obtained results indicated that HAZ, taper angle and surface roughness of holes decreased by ∼30%, ∼47% and ∼43%, respectively, with 1.5 wt% multi-walled carbon nanotubes doped carbon fibre reinforced polymer laminates, when compared with the results obtained from experiments with neat carbon fibre reinforced polymer composite laminates.


2016 ◽  
Vol 857 ◽  
pp. 159-163
Author(s):  
A.A. Sinar ◽  
Z. Firuz ◽  
A.Z. Nur Hidayah ◽  
Md Akil Hazizan ◽  
H.A. Sahrim

The rigid polyurethane (PU) were produced using ionic liquid (IL) modified multi walled carbon nanotubes (MWCNTs) by reaction of palm oil based polyol (POP) with methylene diphenyl diisocyanate (MDI). The 1-butyl-3-methylimidazolium tetrafluoborate (BMIMBF4) used as IL to disperse MWCNTs in PU foam by grinding in ratio 1:3 by weight of MWCNTs to IL till black paste were obtained. The effects of different percentage of modified MWCNTs (0.0 - 3.0 %) on Polyurethane / Multi Walled Carbon Nanotubes / Ionic Liquid (PMI) foam composites were evaluated in density, morphology and compressive strength. The density were increased higher 0.0538 kg / m3 at 3.0 % PMI. The average cell size value higher without addition modified MWCNTs and scanning electron microscopy (SEM) showed inhomogenously structure with addition of modified MWCNTs. Compressive strength with 0.5 % PMI showed the highest value 1.671 MPa compared to other PMI.


Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3567 ◽  
Author(s):  
Bogumiła Kumanek ◽  
Grzegorz Stando ◽  
Paweł S. Wróbel ◽  
Dawid Janas

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.


2015 ◽  
Vol 819 ◽  
pp. 246-250 ◽  
Author(s):  
A.A. Sinar ◽  
Zainuddin Firuz ◽  
M.A. Nur Azni ◽  
A.Z. Nur Hidayah ◽  
Md Akil Hazizan ◽  
...  

This paper describes the effect of multi walled carbon nanotubes (MWCNTs) on the properties, especially the strength properties of rigid polyurethane (PU) foams produced from palm oil based polyol (POP) and methylene diphenyl diisocyanate (MDI). The foam composites in the ratio of 1:1.1 (wt. %) mixed at speed 2000 rpm. The addition of MWCNTs into PU foam are varies from 0 wt. % to 3 wt. %. The properties evaluated were compressive strength, density and energy absorption. Compressive strength of PU foam composites with 0.5% of MWCNTs showed the highest value 1.162 MPa of compressive strength compared to other foam composites. It was proved by modeling displacement nodal magnitude using NX Software (version 8.5). The density was increased 15.69 % with addition of 0.5 % MWCNTs into the PU foam. Increasing the amount of MWCNTs in PU foam was found to improve the energy absorption from 22.89 J for pure PU to 24.53 J for foam composites with 3 % MWCNTs.


Author(s):  
Pawandeep Kaur ◽  
Jaspal Singh ◽  
Manpreet Kaur ◽  
Ritesh Jain

Metakaolin based geopolymer mortars are presently considered as a feasible substitute to Ordinary Portland Cement mortar due to its various benefits. The present experimental investigation is planned by varying the concentrations of sodium hydroxide as 8M, 10M and 12M along with the variation of multi-walled carbon nanotubes (0, 0.25%, 0.50%, 0.75% and 1% by weight of the binder). For each specimen, the compressive strength was determined at the curing ages of 3, 7 and 28 days. The results clearly indicate that the incorporation of multi walled carbon nanotubes (MWCNTs) in the geopolymer matrixes enhances the compressive strength. Transmission electron microscope (TEM) was used to depict the microstructure and morphology of MWCNTs. The ultimate compressive strength was obtained by employing 12M concentrated sodium hydroxide solution along with 0.5% of MWCNTs in geopolymer mortar. The values of integral absolute error were computed for all the curing ages. All the values lie within the acceptable range (0 to 10%).


2020 ◽  
Vol 30 ◽  
pp. 41-54
Author(s):  
Shelan A. Farman ◽  
Muayed K. Ibrahim ◽  
Kadhim A. Aadim

Nanocarbon structures such as graphene (GR), single-walled carbon nanotubes (SWCNTs) as well as the multi-walled carbon nanotubes (MWCNTs) were deposited on crystalline n-type silicon wafers to fabricate nanoCarbon-Si solar cells. Nanocarbon films deposited on glass and porous silicon (PS) via pulse laser deposition (PLD) with the use of Q-Switching Nd: YAG laser with λ=1064 (nm), Energy (E)=700 (mJ), Repetition rate (f)=6 (HZ) under vacuum condition with 2.5×10-2 (mbar). The surface morphology, structure, and optical Nanocarbon thin films have been examined with the use of X-ray Diffraction (XRD), Atomic force microscope (AFM), FTIR spectrophotometer and UV-visible. In addition, the power conversion efficiency that is related to the prepared solar cells is estimated through J-V characterization. The PCE of all Nanocarbon/PS follows the orders; SWCNTs/PS < MWCNTs/PS< GR/PS.


2011 ◽  
Vol 284-286 ◽  
pp. 310-313
Author(s):  
Zhi Gang Liu ◽  
Li Rong Yang ◽  
Jun Cong Wei ◽  
Bao Hui Zhao ◽  
Xiao Xin Feng

The compressive strength and piezoresistive property of cement mortar with low adding level of multi-walled carbon nanotubes (MWCNTs) were investigated. Experimental results showed that the compressive strength of the MWCNTs/cement mortars increased with the adding amount of MWCNTs content for all the curing ages. Silica fume promoted the compressive strength development by well bonding with MWCNTs and filling effect. The electrical resistance changed synchronously with the compressive strength and the amount of the changes varied with the stress and MWCNTs addition levels. Higher MWCNTs doping level improved the piezoresistive sensitivity of the mortar. The mortar with silica fume (5-10% by weight of cement) exhibited better piezoresistive response than that without silica fume at the same MWCNTs doping levels.


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