scholarly journals Morphology and Properties of Aminosilane Grafted MWCNT/Polyimide Nanocomposites

2008 ◽  
Vol 2008 ◽  
pp. 1-15 ◽  
Author(s):  
Siu-Ming Yuen ◽  
Chen-Chi M. Ma ◽  
Chin-Lung Chiang ◽  
Chih-Chun Teng
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Resistivity ◽  
Glass Transition ◽  
Transition Temperature ◽  
Percolation Threshold ◽  
Multiwalled Carbon ◽  
Mwcnt Content ◽  
Glass Transition Temperatures ◽  
Novel Method ◽  
Polyimide Composites

This investigation presents a novel method for modifying multiwalled carbon nanotubes (MWCNTs). The morphology, electrical resistivity, and percolation threshold of MWCNT/Polyimide nanocomposites were studied. Acid-modified MWCNTs reacted with (3-aminopropyl)triethoxysilane by ionic bonding, and were then mixed with polyamic acid via imidization. TEM microphotographs reveal that silane-grafted MWCNTs were connected to each other. The electrical resistivity of silane-grafted MWCNT/polyimide decreased substantially below than that of acid-treated MWCNTs when the silane-modified MWCNT content was lower than 2.4 wt%. The percolation threshold of the MWCNT/polyimide composites is 1.0 wt% for silane-modified MWCNT and exceeds 7.0 wt% for acid-modified MWCNT. The acid-modified MWCNT/polyimide composites possess slightly higher glass transition temperatures than that of pure polyimide. The glass transition temperature of the polyimide increased significantly with silane-modified MWCNT content. Tensile properties of the polyimide have been improved with the MWCNTs content.

scholarly journals Mechanical and Self-Sensing Properties of Multiwalled Carbon Nanotube-Reinforced ECCs

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Chuanbo Liu ◽  
Guozhen Liu ◽  
Zhi Ge ◽  
Yanhua Guan ◽  
Zhiyong Cui ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Percolation Threshold ◽  
Tensile Strain ◽  
The Self ◽  
Fractional Change ◽  
Multiwalled Carbon ◽  
Mwcnt Content ◽  
Sensing Properties ◽  
Midspan Deflection

This paper investigates the effect of type and dosage of multiwalled carbon nanotubes (MWCNTs) on the mechanical and self-sensing properties of engineered cementitious composites (ECCs). Two types of MWCNTs (MWCNTa and MWCNTb) were employed. The tensile and flexural strengths of CNT-reinforced ECCs were improved compared with normal ECCs, while the ultimate tensile strain and midspan deflection were reduced. Compared with the dosage of MWCNTs, the type had less effect on these properties. The percolation threshold was around 0.3 wt.%. ECCs containing MWCNTs had good self-sensing ability under different loading conditions. When the midspan deflection increased from 0.1 to 0.6 mm, the fractional change in resistivity reached 9%. The dosage of MWCNTs had a significant effect on the self-sensing ability. As the MWCNT content increased, the amplitude of fractional change in resistivity decreased.

Study on Tensile and Impact Performance for the MWCNTs/EP Composite

2014 ◽  
Vol 936 ◽  
pp. 390-393
Author(s):  
Fei Yan ◽  
Jing Wen Fu ◽  
Dong Yu Zhao
Keyword(s):  
Carbon Nanotubes ◽  
Tensile Strength ◽  
Glass Transition ◽  
Transition Temperature ◽  
Epoxy Resins ◽  
Volume Resistivity ◽  
Multiwalled Carbon ◽  
Impact Performance ◽  
Percolation Thresholds ◽  
Different Content

In this paper, multiwalled carbon nanotubes (MWCNTs)/epoxy resins (EP) composite was prepared by situ polymerization. MWCNTs/EP composites were prepared with different content of MWCNTs. The study of morphology and properties showed certain content of MWCNTs can well homogeneous dispersed in EP. Since of interface interaction between MWCNTs and EP, the glass transition temperature (Tg), strength and toughness of MWCNTs/EP composites were improved. Compared to the neat EP, composites prepared with 10 wt% MWCNTs showed 20 °C rising in Tg and nine orders of magnitude reduce in volume resistivity. The percolation thresholds between 4 wt% and 6 wt% are observed. Compared to the neat EP, composites prepared with 6 wt% MWCNTs showed with 83 % increase in tensile strength, 83 % increase in elastic modulus and 89 % increase in impact strength.

scholarly journals Structure, thermophysical properties and electrical conductivity of nanocomposites based on epoxy polymer and carbon tubes

2021 ◽  
pp. 7-13
Author(s):  
V.V. Korskanov ◽  
O.M. Fesenko ◽  
V.B. Dolgoshey
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Percolation Threshold ◽  
Thermophysical Properties ◽  
Epoxy Polymer ◽  
Transition Range ◽  
Epoxy Polymers

The aim of this work was to find the optimal conditions for the formation of nanocomposites, study their structure and properties and conditions for the formation of multicomponent materials based on epoxy polymers and carbon nanotubes with predetermined performance properties. The basis for the formation of epoxy polymers was an epoxydian oligomer (EDO) based on bisphenol A. Polypox H354 was used as a hardener for EDO. Carbon nanotubes (CNT) were used as a nanofiller for the preparation of nanocomposites. The research methods were a diffractometer for measuring the intensity of X-ray scattering in the region of small angles and a differential scanning calorimeter for obtaining heating thermograms. The electrical conductivity of the samples at a temperature of 293 K was measured at direct current according to the two-electrode scheme. In this work the structure, thermophysical properties and electrical conductivity of nanocomposites based epoxy polymers and carbon  nanotubes have been studied. It was found that at low CNT content the formation of nanocomposites occurs by the mechanism of epoxy network growth, which is accompanied by the displacement of CNT particles to the periphery of the epoxy matrix. This process is accompanied by an increase in the scattering intensity of the SAXS, a rapid increase in the glass transition temperature and the degree of crosslinking of the epoxy polymer. When the critical concentration is reached, CNT particles form a continuous cluster, which leads to occurrence percolation threshold, reducing the glass transition temperature, expanding the glass transition range, occurrence of pores and reducing the degree of completion of the crosslinking reaction in nanocomposites relative to the epoxy polymer. It is established that the improvement of nanocomposite properties and the occurrence of the percolation threshold is due to the maximum specific energy of ER-CNT interaction and is achieved at a critical mass concentration of nanofiller from 0,1% to 0,4%.

scholarly journals Depression in glass transition temperature of multiwalled carbon nanotubes reinforced polycarbonate composites: effect of functionalization

RSC Advances ◽  
2015 ◽  
Vol 5 (54) ◽  
pp. 43462-43472 ◽  
Author(s):  
Arun Singh Babal ◽  
Ravi Gupta ◽  
Bhanu Pratap Singh ◽  
Sanjay R. Dhakate
Keyword(s):  
Carbon Nanotubes ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Storage Modulus ◽  
Multiwalled Carbon Nanotubes ◽  
Multiwalled Carbon ◽  
Functionalized Mwcnts

Acid functionalized MWCNTs/PC composites showed significant improvement in storage modulus upto 57% in glassy and 400% in rubbery region over pure polycarbonate.

Synthesis of aligned carbon nanotubes in organic liquids

2002 ◽  
Vol 17 (9) ◽  
pp. 2457-2464 ◽  
Author(s):  
Yafei Zhang ◽  
Mikka N.-Gamo ◽  
Kiyoharu Nakagawa ◽  
Toshihiro Ando
Keyword(s):  
Carbon Nanotubes ◽  
Organic Liquid ◽  
Film Surface ◽  
Normal Pressure ◽  
Organic Liquids ◽  
X Ray Diffraction ◽  
Multiwalled Carbon ◽  
Aligned Carbon Nanotubes ◽  
Novel Method ◽  
The Right

A simple and novel method was developed for efficient synthesis of aligned multiwalled carbon nanotubes (CNTs) in methanol and ethanol under normal pressure. The CNTs' alignment and structures were investigated using Raman scattering and x-ray diffraction spectroscopy. A unique kind of coupled CNT was synthesized in which one rotated to the left and one rotated to the right. Chains periodically bridged the coupled CNTs. The growth mechanism of the CNTs within organic liquid is proposed to be a catalytic process at the Fe film surface in a dynamic and thermal nonequilibrium condition in organic liquids.

A Copolymerization Modified Acrylate Resin and its Polyhedral Oligomeric Silsesquioxane Composites

2014 ◽  
Vol 887-888 ◽  
pp. 97-100
Author(s):  
Xiao Lan Hu ◽  
Xi Lan ◽  
Teng Fei Lu ◽  
Hong Shan Yang ◽  
Ying Lai Yang
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
Glass Transition Temperatures ◽  
Acrylate Copolymer ◽  
Amino Resin ◽  
Acrylate Resin ◽  
Oligomeric Silsesquioxane ◽  
Physical Blending ◽  
Better Than

An acrylate resin copolymerized with epoxy and amino resin was prepared in this paper, and its polyhedral oligomeric silsesquioxane (POSS) modified nanocomposites were fabricated via physical blending. Results showed that glass transition temperature of the acrylate copolymer was about 7.9 oC via DSC. Dispersion of nanocomposites with aminopropyllsobutyl POSS is better than those with Octalsobutyl POSS. Moreover, glass transition temperatures of the nanocomposites with POSS are close to the acrylate copolymer matrix.

Observation of Glass Transition Temperatures in Polymeric Thin Films by Wafer Curvature Measurements

1991 ◽  
Vol 239 ◽  
Author(s):  
P. H. Townsend ◽  
B. S. Huber ◽  
D. S. Wang
Keyword(s):  
Thin Films ◽  
Glass Transition ◽  
Transition Temperature ◽  
Polymer Network ◽  
Cross Linking ◽  
Positional Isomers ◽  
Glass Transition Temperatures ◽  
Thin Coatings ◽  
Polymeric Thin Films ◽  
Curvature Measurements

ABSTRACTWafer bending measurements have been used to study the glass transition temperature, Tg, of thin coatings of polystyrene and polycarbonate on Si wafers. The observed values of Tg agree with DSC and TMA measurements on bulk samples. The evolution of the substrate curvature has been used to examine the behavior of Tg in thin epoxy films and coatings derived from divinylsiloxane bisbenzocyclobutene, mixed stereo and positional isomers of 1, 3-bis(2-bicyclo[4.2.0]octa-1, 3, 5-trien-3-ylethenyl)-1, 1, 3, 3-tetramethyl disitoxane (CAS 117732–87–3). The dependence of the Tg of the epoxide coatings is studied as a function of the cross-linking. The evolution of the Tg in the benzocyclobutene coating is found to be a monotonie function of the level of conversion of the polymer network.

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