Effect of Dispersion Conditions on the Thermal and Mechanical Properties of Carbon Nanofiber–Polyester Nanocomposites

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
M. E. Hossain ◽  
M. K. Hossain ◽  
M. V. Hosur ◽  
S. Jeelani
Keyword(s):  
Carbon Nanofiber ◽  
Fracture Morphology ◽  
Xrd Analysis ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Compression Tests ◽  
Static Compression ◽  
Mechanical Responses ◽  
The Matrix ◽  
Dispersion Technique

In this study, sonication dispersion technique was employed to infuse 0.1–0.4 wt.% carbon nanofibers (CNFs) into polyester matrix to enhance thermomechanical properties of resulting nanocomposites. The effect of dispersion conditions has been investigated with regard to the CNF content and the sonication time. X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) micrographs revealed excellent dispersion of 0.2 wt.% CNF infused in polyester, resulting in enhanced mechanical responses. Polyester with 0.2 wt.% CNF samples resulted in 88% and 16% increase in flexural strength and modulus, respectively, over the neat one. Quasi-static compression tests showed similar increasing trend with addition of CNF. Fracture morphology study of tested samples revealed relatively rougher surface in CNF-loaded polyester compared to the neat due to better interaction between the fiber and the matrix. Dynamic mechanical analysis (DMA) study exhibited about 35% increase in the storage modulus and about 5 °C increase in the glass transition temperature (Tg). A better thermal stability in the CNF-loaded polyester was observed from the thermogravimetric analysis (TGA) studies. Best results were obtained for the 0.2 wt.% CNF loading with 90 mins of sonication and 50% sonication amplitude. It is recommended that this level of sonication facilitates suitable dispersion of the CNF into polyester matrices without destroying the CNF's structure.

Study of Mechanical Responses and Thermal Expansion of CNF-modified Polyester Nanocomposites Processed by Different Mixing Systems

2011 ◽  
Vol 1312 ◽  
Author(s):  
Muhammad E. Hossain ◽  
Mohammad K. Hossain ◽  
Mahesh Hosur ◽  
Shaik Jeelani
Keyword(s):  
Thermal Expansion ◽  
Mechanical Response ◽  
Carbon Nanofiber ◽  
Coefficient Of Thermal Expansion ◽  
Fracture Morphology ◽  
Mechanical Analysis ◽  
Mechanical And Thermal Properties ◽  
Compression Tests ◽  
Mechanical Mixing ◽  
Static Compression

ABSTRACTIn this study, different dispersion techniques such as sonication at high frequency, mechanical mixing, and magnetic stirring methods were employed to infuse 0.1 to 0.4 wt.% carbon nanofiber (CNF) into polyester matrix to study the influence of CNF on mechanical and thermal properties of the polyester nanocomposites. Dispersion of CNF studied using scanning electron microscopy (SEM) micrographs revealed excellent dispersion of CNF using sonication when 0.2 wt.% CNF was mixed in polyester resulting in enhanced mechanical response. On the other hand, agglomerations were observed in samples prepared with other mixing methods. Polyester with 0.2 wt.% CNF samples prepared by sonication resulted in 88% and 16% increase in flexural strength and modulus, respectively, over neat samples. Quasi-static compression tests showed similar increasing trend with addition of 0.2 wt.% CNF. Dynamic mechanical analysis (DMA) showed 35% and 5 °C improvement in the storage modulus and glass transition temperature (Tg), respectively, in the 0.2 wt.% loaded samples. Thermal mechanical analysis (TMA) performed on neat and samples with 0.2 wt.% CNF showed lower coefficient of thermal expansion (CTE) in nanophased sample compared to neat. Fracture morphology evaluated using SEM revealed relatively rougher surface in CNF-loaded polyester compared to neat as a result of better interaction between fiber and matrix due to the presence of CNF.

Functionally Graded Nanocomposites: Manufacturing and Characterization

Aerospace ◽  
2006 ◽  
Author(s):  
Jared A. Rud ◽  
Yuri M. Shkel ◽  
Donald R. Matthys ◽  
Jeffrey P. Davidson
Keyword(s):  
Electric Field ◽  
Carbon Nanofiber ◽  
Speckle Pattern ◽  
Matrix Material ◽  
Mechanical Analysis ◽  
Functionally Graded ◽  
Electronic Speckle Pattern Interferometry ◽  
Random Orientation ◽  
The Matrix ◽  
Particle Alignment

Multi-walled carbon nanofiber (MWCN) composites having tailored internal structure are created using Field Aided Micro Tailoring (FAiMTa) technology. FAiMTa is a technique that relies on the application of an electric field to a suspension while it cures. The particles in the suspension align in the direction of the electric field while the matrix material hardens, locking the aligned particles in place. The outcome is an orthotropic micro-tailored composite. Three 1% by volume MWCN/epoxy composite systems are manufactured and characterized: (a) random orientation, (b) fibers aligned through the thickness of the sample, and (c) half-aligned through the thickness and half random orientation. Electronic Speckle Pattern Interferometry (ESPI) and Dynamic Mechanical Analysis (DMA) are used to evaluate mechanical material properties as a function of particle alignment. The half aligned sample demonstrates the ability of FAiMTa to locally tailor a material.

Actuation of Shape Memory Polymer by Resistive Heating of Carbon Nanopaper

2009 ◽  
Author(s):  
Haibao Lu ◽  
Yong Tang ◽  
Jihua Gou ◽  
Erin Chow ◽  
Jinsong Leng ◽  
...  
Keyword(s):  
Shape Memory ◽  
Shape Recovery ◽  
Carbon Nanofiber ◽  
Volume Fraction ◽  
Shape Memory Polymer ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Paper Sheet ◽  
Scanning Electron ◽  
Properties Of Composites

To electrically activate the shape recovery in a styrene-based shape-memory polymer (SMP) by coating with conductive carbon nanofiber paper has been demonstrated in this paper. Carbon nanofibers in the form of paper sheet in combination with SMP significantly improve the electrical and thermal conductivity of polymer, leading to the actuation of SMP/nanopaper composite (with 15% volume fraction of carbon nanopaper, dimension of 10.0 cm × 0.5 cm × 0.3 cm) can be carried out by applying 8.4 V voltage, with response time of 140 s. Therefore, electrical conductivity of 6.6 S/cm is obtained. This approach, although demonstrated in styrene-based polymer, is applicable to other type of SMP materials. Furthermore, the morphologies of carbon nanofiber in the form of paper is observed by scanning electron microscopy, and the thermomechanical properties of composites are measured and analyzed by dynamic mechanical analysis.

CARBON NANOFIBER COMPOSITE WITH EPDM AND POLYIMIDE FOR HIGH-TEMPERATURE INSULATION

2014 ◽  
Vol 87 (4) ◽  
pp. 593-605 ◽  
Author(s):  
Sangita Singh ◽  
P. K. Guchhait ◽  
N. K. Singha ◽  
T. K. Chaki
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Carbon Nanofiber ◽  
Oxidative Degradation ◽  
Thermomechanical Properties ◽  
Scanning Calorimetry ◽  
Additional Advantage ◽  
Morphological Studies ◽  
Uniform Dispersion ◽  
The Matrix

ABSTRACT Elastomers and their composites are extensively used as a thermal insulation system in heat treatment, power generation, fire protection, and aerospace. Among different elastomers, low-density ethylene propylene diene terpolymer (EPDM) has interesting properties, such as excellent resistance to aging and oxidative degradation due to its saturated back bone. Furthermore, introduction of polyimide (PI) to the base elastomer increases its thermal stability. On the other hand, carbon nanofiber (CNF) reinforces the matrix to enhance the mechanical properties with an additional advantage of better char yield. To achieve better rubber-filler compatibilization, modification of EPDM was carried out by grafting with maleic anhydride (MAH). Morphological studies by scanning electron microscopy and high-resolution transmission electron microscopy exhibited uniform dispersion of nanofillers throughout MAH grafted EPDM matrix. Thermal properties of the EPDM/PI nanocomposites were characterized by thermogravimetric analysis and differential scanning calorimetry. Besides these, thermal conductivity, thermal diffusivity, and specific heat were also measured. PI- and CNF-filled maleated EPDM composites showed very good physical and thermomechanical properties for high-temperature insulation compound.

Nano-Engineering Silica Aerogel Structure to Determine the Property-Structure Relationship

2009 ◽  
Author(s):  
Gitogo Churu ◽  
Hongbing Lu ◽  
Nicholas Leventis
Keyword(s):  
Silica Aerogel ◽  
Sol Gel ◽  
Mechanical Analysis ◽  
Honeycomb Structure ◽  
Material Point ◽  
Compression Tests ◽  
Structure Directing Agent ◽  
Static Compression ◽  
Pluronic P123 ◽  
Structure Relationship

We characterize mechanically strong nano/meso-porous cross-linked templated silica aerogels that were synthesized through the sol gel process and reinforced by nano casting a 4–10nm thick conformal layer of isocynate derived polymer. Tri-block co-polymer (pluronic P123) was used as a structure directing agent to produce ordered mesoporous walls while 1, 3, 5 trimethylbenzene (TMB) was added as micelle-swelling reagent to regulate the size of the pores. The shape and size of the micro and meso pores were nano engineered by varying the amount of chemical surfactant as well as the concentration of the cross-linking solution used to form the polymer nano layer. In so doing we manipulated the structure at the molecular level to develop an optimized structure that closely resembles the honeycomb structure found in nature. Dynamic mechanical analysis (DMA) test results established that the material had an α-grass transition temperature of about 130°C while quasi-static compression tests showed that the optimized nano-structured silica aerogel had a Young’s modulus of about 800MPa. We present the synthesis protocol as well as chemical, physical and mechanical characterization of cross-linked templated silica aerogel (CTSA). ). In addition, material point method (MPM) simulation results are highlighted.

TITANIUM-CARBIDE-INFUSED PHENOLIC BALSA FOAM NANOCOMPOSITE

2008 ◽  
Vol 07 (04n05) ◽  
pp. 235-243 ◽  
Author(s):  
VIJAYA K. RANGARI ◽  
TARIG A. HASSAN ◽  
CLIFTON MAYO ◽  
SHAIK JEELANI
Keyword(s):  
Electron Microscopy ◽  
Titanium Carbide ◽  
High Speed ◽  
Foam Cell ◽  
Compression Tests ◽  
Scanning Calorimetry ◽  
Entire Volume ◽  
Static Compression ◽  
The Matrix ◽  
Resin Solution

A sonochemical technique is developed to infuse titanium carbide nanoparticles into phenolic balsa foam material. Commercially available phenolic balsa foam resin solution (part A) is mixed with titanium carbide ( TiC ~ 80 nm ) nanoparticles, and irradiated with a high intensity ultrasonic horn. In the next step, the modified phenolic balsa foam resin solution containing titanium carbide nanoparticles is mixed with part B (containing phenol sulfonic acid, a catalyst) through a high speed mechanical stirrer. The reaction mixture is then cast into a rectangular mold to fabricate nanophased foam panels. Test coupons are cut precisely from the panels to carry out thermal, morphological and mechanical characterizations. The as-prepared foams are characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The SEM studies show that the particles are well dispersed over the entire volume of the matrix, with minimal agglomeration. The foam cell structures are well-ordered and uniform in size and shape. The TGA analysis indicates that the nanophased foams are thermally more stable than the corresponding neat systems. Quasi-static compression tests have been carried out for both nanophased and neat foam systems. The test results show a significant increase in the compressive strength (108%) and modulus (135%) compared to the neat system. These improvements in compressive properties have been observed repeatedly for multiple batches and with a minimum of five specimens tested from each batch. Details of the synthesis procedure and thermal and mechanical characterizations are presented in this paper.

scholarly journals Influence of Silanization Treatment on Thermomechanical Properties of Multiwalled Carbon Nanotubes: Poly(methylmethacrylate) Nanocomposites

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Carlos Velasco-Santos ◽  
Ana Laura Martinez-Hernandez ◽  
Witold Brostow ◽  
Victor M. Castaño
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Polymer Matrix ◽  
Mechanical Load ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Multiwalled Carbon ◽  
Dynamical Mechanical Analysis ◽  
The Matrix

Unfunctionalized and silanized multiwalled carbon nanotubes (MWNTs) were incorporated in poly(methylmethacrylate) matrices usingin situpolymerization. Polymer-compatible functional groups on carbon nanotube (CNT) surfaces were characterized by infrared spectroscopy. These chemical moieties improve interaction at interfaces, allowing transfer of mechanical load between the matrix and the dispersed phase as reflected in the resulting improved mechanical and thermophysical properties. The composites were characterized by Raman spectroscopy to evaluate molecular level interactions and dynamical mechanical analysis. Composites with silanized CNTs have higher storage modulus (E′) than polymer reinforced with unfunctionalized nanotubes. Considering the average of the samples, only 1 wt.% of silanized nanotubes provides an increase inE′ of 165% at room temperature with respect to polymer matrix, and the increments reached are by a factor of 6.8 and 13.6 over the polymer matrix at 80°C and 90°C, respectively. 1 wt% of silanized CNTs increases the glass transition temperature of polymer matrix around 30°C. Microscratch testing results of composites show that unfunctionalized CNTs cause deeper penetration of the indenter than polymer matrix at the same force; however, the composites developed with silanized CNTs present more regular behavior than polymer reinforced with unfunctionalized CNTs.

Microstructure and Mechanical Properties Change with Cold Deformation of the Biomedical Ti-17Nb-6Ta-3Zr Alloy

2018 ◽  
Vol 780 ◽  
pp. 15-19 ◽  
Author(s):  
Kudakwashe Nyamuchiwa ◽  
Mohamed Abdel Hady Gepreel ◽  
Atef Hamada ◽  
Koichi Nakamura
Keyword(s):  
Mechanical Properties ◽  
Cold Deformation ◽  
Young Modulus ◽  
Xrd Analysis ◽  
Structure Characterization ◽  
Compression Tests ◽  
Static Compression ◽  
Bcc Structure ◽  
Cold Worked ◽  
The Stability

This study is to investigate the phase stability, cold deformation, elastic strain recovery and mechanical properties of a new Ti-17Nb-6Ta-3Zr, at. %, alloy for biomedical applications. The alloy was produced by arc melting. A heavy cold-working up to 90 % was applied to the alloy to investigate the stability of the predominant β-bcc structure. Characterization of the deformed structures was performed by X-ray diffraction (XRD), hardness measurements and optical microscopy. Quasi-static compression testing was conducted to determine the yield stress for stress induced martensitic (SIM) transformation and the Young modulus. XRD analysis of the cold-worked structures revealed that α-martensite was induced after less than 5 % deformation. An outstanding combination of strength-elasticity properties with the yield strength of 600 MPa and a Young modulus of 37 GPa was achieved during the compression tests.

Influence of filler hybridization on thermomechanical properties of hemp/silver epoxy composite

2020 ◽  
pp. 096739112097811
Author(s):  
Munjula Siva Kumar ◽  
Santosh Kumar ◽  
Krushna Gouda ◽  
Sumit Bhowmik
Keyword(s):  
Thermal Conductivity ◽  
Silver Nanoparticles ◽  
Epoxy Polymer ◽  
Hybrid Composites ◽  
Conductive Filler ◽  
Weight Fraction ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Material Behavior ◽  
Good Crystallinity

The polymer composite material’s thermomechanical properties with fiber as reinforcement material have been widely studied in the last few decades. However, these fiber-based polymer composites exhibit problems such as fiber orientation, delamination, fiber defect along the length and bonding are the matter of serious concern in order to improve the thermomechanical properties and obtain isotropic material behavior. In the present investigation filler-based composite material is developed using natural hemp and high thermal conductive silver nanoparticles (SNP) and combination of dual fillers in neat epoxy polymer to investigate the synergetic influence. Among various organic natural fillers hemp filler depicts good crystallinity characteristics, so selected as a biocompatible filler along with SNP conductive filler. For enhancing their thermal conductivity and mechanical properties, hybridization of hemp filler along with silver nanoparticles are conducted. The composites samples are prepared with three different combinations such as sole SNP, sole hemp and hybrid (SNP and hemp) are prepared to understand their solo and hybrid combination. From results it is examined that, chemical treated hemp filler has to maximized its relative properties and showed, 40% weight % of silver nanoparticles composites have highest thermal conductivity 1.00 W/mK followed with hemp filler 0.55 W/mK and hybrid 0.76 W/mK composites at 7.5% of weight fraction and 47.5% of weight fraction respectively. The highest tensile strength is obtained for SNP composite 32.03 MPa and highest young’s modulus is obtained for hybrid composites. Dynamic mechanical analysis is conducted to find their respective storage modulus and glass transition temperature and that, the recorded maximum for SNP composites with 3.23 GPa and 90°C respectively. Scanning electron microscopy examinations clearly illustrated that formation of thermal conductivity chain is significant with nano and micro fillers incorporation.

Fabrication of Bulk Functionally-Graded Syntactic Foams for Impact Energy Absorption

2012 ◽  
Vol 706-709 ◽  
pp. 711-716 ◽  
Author(s):  
Tadaharu Adachi ◽  
Masahiro Higuchi
Keyword(s):  
Theoretical Analysis ◽  
Energy Absorption ◽  
Functionally Graded ◽  
Fabrication Process ◽  
Syntactic Foams ◽  
Compression Tests ◽  
Matrix Resin ◽  
Local Fracture ◽  
Density Distributions ◽  
The Matrix

Function of functionally-graded (FG) foams as energy absorption material for impact was discussed on the basis of theoretical analysis, and fabrication process of the foams was proposed in the paper. The FG foams were found to be useful as impact absorber due to progressively local fracture or cushion in the theoretical analysis. Next the fabrication process of the FG foams was suggested. The graded dispersion of the micro-balloons was conducted before curing the matrix resin in the process. The density distributions in the FG foams were confirmed to be predicted by the numerical analysis on the basis of floating the micro-balloons. Finally, compression tests were carried out to evaluate mechanical properties.

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