Thermo-mechanical properties of epoxy nanocomposites incorporating amino acid and acid functionalized multi-walled carbon nanotubes

2019 ◽  
Vol 54 (14) ◽  
pp. 1847-1861
Author(s):  
Alireza Bagherzade ◽  
Masoud Jamshidi

In this study, multi-walled carbon nanotubes (MWCNTs) were functionalized by both sulfuric/nitric acids and amino acids to form COOH and NH2/COOH/OH groups on their surface, respectively. The functionalized MWCNTs were characterized by Fourier Transform Infrared Spectroscopy, titration test, thermal gravimetric analysis, and solvent stability test. The results revealed that in each method, the functional groups were successfully attached to the surface of nanotubes. Acid treatment grafted more oxygen-containing groups compared to commercial carboxylated MWCNTs. The amino acid functionalized MWCNTs indicated improved stability in different solvents compared to raw and acid treated MWCNTs. These functionalized MWCNTs were incorporated into epoxy resin and the properties of the nanocomposites were evaluated by scanning electron microscopy, tensile test, dynamic mechanical thermal analysis, differential scanning calorimetry, and thermogravimetric analysis. The morphology of the nanocomposites revealed that acid and amino acid treated samples had better interaction with the epoxy resin. Compared to epoxy sample contained raw MWCNT (control) and commercial carboxylated MWCNTs, the addition of functionalized MWCNTs to the epoxy resin improved the tensile strength by 39% and 25% (for acid treated) and 46% and 33% (for amino acid treated), respectively. The best tensile properties for acid and amino acid treated samples were reached by MWCNTs acid treated at 110℃ for 15 min and MWCNTs treated in a 50 g/L aqueous solution of amino acid, respectively. Storage modulus of the epoxy samples which contained acid and amino acid treated MWCNTs were 1560 and 1900 MPa, respectively. The glass rubber transition temperature ( Tg) of the epoxy samples containing acid and amino acid treated nanotubes were increased by 1.1℃ and 5.9℃, respectively, compared to the control sample. Therefore, based on these mechanical properties, the epoxy samples containing nanotubes functionalized by amino acid exhibited the highest performance in the epoxy nanocomposite. Incorporating acid and amino acid treated MWCNTs accelerated the curing process of epoxy where the curing temperature decreased by 9.1℃ and 13.3℃, respectively. Because of the reaction between amine groups grafted on MWCNTs in the amino acid treatment and epoxide groups of the epoxy resin, this acceleration was more significant in the case of amino acid sample. Note that addition of functionalized MWCNTs to epoxy resin did not lead to increased thermal stability.

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Seyed Ali Mirsalehi ◽  
Amir Ali Youzbashi ◽  
Amjad Sazgar

AbstractIn this study, epoxy hybrid nanocomposites reinforced by carbon fibers (CFs) were fabricated by a filament winding. To improve out-of-plane (transverse) mechanical properties, 0.5 and 1.0 Wt.% multi-walled carbon nanotubes (MWCNTs) were embedded into epoxy/CF composites. The MWCNTs were well dispersed into the epoxy resin without using any additives. The transverse mechanical properties of epoxy/MWCNT/CF hybrid nanocomposites were evaluated by the tensile test in the vertical direction to the CFs (90º tensile) and flexural tests. The fracture surfaces of composites were studied by scanning electron microscopy (SEM). The SEM observations showed that the bridging of the MWCNTs is one of the mechanisms of transverse mechanical properties enhancement in the epoxy/MWCNT/CF composites. The results of the 90º tensile test proved that the tensile strength and elongation at break of nanocomposite with 1.0 Wt.% MWCNTs improved up to 53% and 50% in comparison with epoxy/CF laminate composite, respectively. Furthermore, the flexural strength, secant modulus, and elongation of epoxy/1.0 Wt.% MWCNT/CF hybrid nanocomposite increased 15%, 7%, and 9% compared to epoxy/CF laminate composite, respectively.


2014 ◽  
Vol 893 ◽  
pp. 241-244
Author(s):  
Yong Hui Lv ◽  
Bao Xiang Deng

The acidified multi-walled carbon nanotubes (MWNTs-COOH) was obtained by nitric acid treatment on multi-walled carbon nanotubes (MWNTs).The PI/MWNTs-COOH composite films were synthesized by in situ polymerization. The thermal stability, resistance and mechanical properties of PI/MWNTs-COOH composite were evaluated. The results showed that: the composites maintained a good thermal stability with the addition of the MWNTs-COOH; the resistance of the composite film dropped at first, and rose up later. While the tensile strength increased at first and then decreased. In conclusion, the PI/MWNTs-COOH composite films exhibited better thermal, antistatic and mechanical properties compared with neat PI.


2021 ◽  
pp. 095400832199209
Author(s):  
Hermawan Judawisastra ◽  
Christian Harito ◽  
Dika Anindyajati ◽  
Hengky Purnama ◽  
Akbar Hanif Dawam Abdullah

The effects of composite fabrication, such as pre-curing, curing temperature, and cooling rate, were studied. In this work, the pre-curing was defined as heat treatment of Multi-Walled Carbon Nanotubes (MWNCTs) with Diglycidyl Ether of Bisphenol A (DGEBA) epoxy resin. Acid purified MWCNTs were characterized by Raman spectroscopy and Fourier Transform Infrared Spectroscopy (FTIR). The pre-curing facilitated bonding between MWCNTs and epoxy via the oxirane ring of DGEBA, which accelerated the curing process of epoxy and increased mechanical properties. The elevated curing temperature on the pre-cured sample further improved the composite’s mechanical properties by increasing interfacial bonding due to cross-linking. The rapid cooling using liquid nitrogen during pre-curing treatment prevented re-agglomeration of MWCNTs, showing smaller agglomerates and improving the mechanical properties. Agglomeration was characterized by scanning electron microscopy, while the bonding between MWCNTs and epoxy was examined by the length of fibre pull-out on the fracture surface. Tensile testing was deployed for mechanical properties characterization. The degree of cure was determined by FTIR and Differential Thermal Analysis (DTA).


2010 ◽  
Vol 18 (6) ◽  
pp. 1397-1407 ◽  
Author(s):  
Parveen Garg ◽  
Bhanu Pratap Singh ◽  
Gaurav Kumar ◽  
Tejendra Gupta ◽  
Indresh Pandey ◽  
...  

Author(s):  
Shaik Zainuddin ◽  
Mahesh Hosur ◽  
Harish Rao ◽  
Rajib Barua ◽  
Shaik Jeelani ◽  
...  

In this work, SC-15 epoxy resin was modified using 0.1–0.3 wt. % of non-functionalized and functionalized multi-walled carbon nanotubes (MWCNTs) using conventional and solvent based methods. A high-intensity ultrasonic liquid processor was used to disperse MWCNTs in solvent and to obtain a homogeneous molecular mixture of epoxy resin and MWCNTs. Viscosity, dynamic mechanical analysis (DMA), thermo-gravimetric analysis (TGA), tensile and flexure tests were performed on unfilled and 0.1–0.3 wt. % MWCNTs filled SC-15 epoxy. Preliminary results indicate increase in viscosity with increase in MWCNTs wt. % loading and 0.2 wt. % MWCNTs epoxy samples showed the highest improvement in tensile and flexural properties as compared to the neat system. DMA studies also revealed that 0.2 wt. % doped system exhibit the highest storage modulus and Tg as compared to neat and other loading percentages. TGA results show that amino functionalized MWCNTs samples are more thermally stable.


2019 ◽  
pp. 089270571988601 ◽  
Author(s):  
Sahil Kapoor ◽  
Meenakshi Goyal ◽  
Prashant Jindal

Nanocomposites of acrylonitrile butadiene styrene (ABS) with multi-walled carbon nanotubes (MWCNTs) have been fabricated using a facile solution blending technique with the variable weight of MWCNTs in ABS within a range of 1–5 wt% in the ABS/MWCNTs nanocomposites. Morphological characterization using field emission scanning electron microscope has shown uniform dispersion of MWCNTs in the nanocomposites. Thermal gravimetric analysis has shown improved thermal degradation stability for 5 wt% ABS/MWCNTs nanocomposites in comparison to pure ABS. Thermal expansion analysis of ABS/MWCNTs nanocomposites also showed a significant reduction in thermal strain and coefficient of thermal expansion (CTE) in comparison to pure ABS, with the 5 wt% sample showing a maximum reduction in thermal expansion properties. Mechanical characterization for 5 wt% ABS/MWCNTs nanocomposite, using nanoindentation, showed significant improvement in elastic modulus (90%) and hardness (99%) in comparison to pure ABS. The dynamic mechanical properties of 5 wt% ABS/MWCNTs nanocomposites also showed significant improvement with storage modulus and hardness improving by 153% and 342%, respectively, in comparison to pure ABS. These enhanced thermal and mechanical properties of ABS/MWCNTs nanocomposites enable their applications for a wider scope in various areas of engineering-based application, especially in the automobile industry.


2006 ◽  
Vol 505-507 ◽  
pp. 1075-1080 ◽  
Author(s):  
Kuang Chyi Lee ◽  
Hsin Her Yu ◽  
Shug June Hwang ◽  
Ye Shiu Li ◽  
Min Hsun Cheng ◽  
...  

In this study, the surfaces of the multi-walled carbon nanotubes (MWNTs) were treated by acrylic acid. The acid-treated MWNTs were functionalized and were characterized by Infrared spectroscopy. The MWNTs were opened at their ends by ultrasonic treating and UV irradiating. Different adding amounts of the opened MWNTs were filled to the epoxy resin, and their mechanical properties and thermal properties were measured by Instron, impact and differential scanning calorimeter (DSC), etc. The optimum adding amount of MWNTs to the epoxy resin is 2.0%, which is according to the parameters obtained from mechanical testing and Tg. The activation energy of the epoxy resin during curing can be calculated from infrared spectra according to the change of the epoxide band. The electrical conductivity of the MWNTs-filled composites was increased with proper (12.87%) amount of MWNTs adding, this is due to the networks constructed between MWNTs completely.


2021 ◽  
pp. 002199832199161
Author(s):  
Mingrui Liu ◽  
Qiong Rao ◽  
Yingyu Wang ◽  
Xiongqi Peng

A new method of grafting multi-walled carbon nanotubes (MWCNTs) onto carbon fiber surface to improve the thermo-mechanical properties of woven carbon fabric reinforced composites was proposed. In this method, both carbon woven fabrics and MWCNTs were oxidized by sulfuric acid to generate carboxyl groups on their surfaces, respectively. Then silane coupling agent was used to react with the carboxyl groups to graft MWCNTs onto the carbon fiber surfaces of the woven fabric. The untreated, acid treated and MWCNTs grafted carbon woven fabrics were separately combined with polypropylene films to form composite plates by thermal-stamping. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy were conducted to estimate the changes of element contents and functional groups on surfaces of carbon fibers and MWCNTs. Atomic force microscope was used to estimate the roughness of carbon fiber surfaces. Scanning electron microscopy, differential scanning calorimeter, dynamic mechanical thermal analysis and tensile tests were carried out to analyze the surface morphology, thermal, and mechanical properties of carbon fabrics and their composites. Testing results showed that MWCNTs could be successfully grafted onto the carbon fibers by using silane as an intermediate bridge. Compared with the untreated and acid treated composites, the in-plane shearing stiffness and fracture strength of the composites were increased significantly by MWCNTs grafting. In terms of thermal properties, acid treatment and MWCNTs grafting have little effect on melting point of composites. MWCNTs can promote the recrystallization process of the PP and reduce the numbers of imperfect crystals. As for thermo-mechanical properties, acid treatment deteriorated the bending storage modulus of the composite, while MWCNTs grafting could compensate it.


2019 ◽  
Vol 73 (3) ◽  
pp. 183-196 ◽  
Author(s):  
Nevena Vukic ◽  
Ivan Ristic ◽  
Milena Marinovic-Cincovic ◽  
Radmila Radicevic ◽  
Branka Pilic ◽  
...  

This paper presents influence of the type of carbon nanotube functionalization on properties of poly(L-lactide) (PLLA) based nanocomposite materials. For this purpose surface modifications of multi-walled carbon nanotubes (MWCNTs) were performed by chemical and irradiation techniques, while thermo gravimetric analysis, UV-Visible and Fourier-transform infrared (FT-IR) spectroscopies confirmed successful covalent functionalization. Series of PLLA bionanocom-posites with different contents of functionalized MWCNTs (0.7; 1.6; 2.1 wt%), were synthesized via ring-opening solution polymerisation of L-lactide. FT-IR analysis confirmed that grafting of L-lactide, under controlled condition, is possible to perform starting from the surface of functionalized MWCNTs. From differential scanning calorimetry results it was concluded that even low contents of chemically and irradiation functionalized MWCNTs had a significant effect on thermal properties of the prepared nanocomposites, raising the values of melting and glass transition temperatures. Thermogravimetric analysis (TGA) has shown that the degradation onset temperature for composites with chemically functionalized MWCNTs, was much higher than that for the neat poly(L-lactide) sample and composites with irradiation functionalized MWCNTs. Morphology studies by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicated that poly(L-lactide) covered surfaces and separated functionalized MWCNTs. Good dispersion of carbon nanotubes in polymer matrix enabled conductivity of synthesized materials, as determined by conductivity tests.


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