scholarly journals Mechanical, Electrical and Rheological Behavior of Ethylene-Vinyl Acetate/Multi-Walled Carbon Nanotube Composites

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1300 ◽  
Author(s):  
Stanciu ◽  
Stan ◽  
Sandu ◽  
Susac ◽  
Fetecau ◽  
...  
Keyword(s):  
Vinyl Acetate ◽  
Mechanical Response ◽  
Ethylene Vinyl Acetate ◽  
Flow Index ◽  
Melt Temperature ◽  
High Shear Rates ◽  
Nanotube Composites ◽  
Multi Walled Carbon Nanotubes ◽  
Rheological Experiments ◽  
Walled Carbon Nanotubes

This paper investigates the rheological, mechanical and electrical properties of a Ethylene-Vinyl Acetate (EVA) polymer filled with 1, 3 and 5 wt.% multi-walled carbon nanotubes (MWCNTs). The melt flow and pressure-volume-Temperature (pvT) behaviors of the EVA/MWCNT composites were investigated using a high-pressure capillary rheometer, while the electro-mechanical response was investigated on injection-molded samples. Rheological experiments showed that the melt shear viscosity of the EVA/MWCNT composite is dependent on nanotube loading and, at high shear rates, the viscosity showed temperature-dependent shear thinning behavior with a flow index n < 0.35. The specific volume of the EVA/MWCNT composite decreased with increasing pressure and MWCNT wt.%. The transition temperature, corresponding to the pvT crystallization, increased linearly with increasing pressure, i.e., about 20 to 30 °C when cooling under pressure. The elastic modulus, tensile strength and stress at break increased with increasing MWCNT wt.%, whereas the strain at break decreased, suggesting the formation of MWCNT secondary agglomerates. The electrical conductivity of the EVA/MWCNT composite increased with increasing MWCNT wt.% and melt temperature, reaching ~10−2 S/m for the composite containing 5 wt.% MWCNTs. Using the statistical percolation theory, the percolation threshold was estimated at 0.9 wt.% and the critical exponent at 4.95.

Melt Shear Rheology and pVT Behavior of Polypropylene / Multi-Walled Carbon Nanotube Composites

2018 ◽  
Vol 55 (4) ◽  
pp. 482-487 ◽  
Author(s):  
Nicoleta Violeta Stanciu ◽  
Felicia Stan ◽  
Catalin Fetecau
Keyword(s):  
Superposition Principle ◽  
Melt Temperature ◽  
Shear Rates ◽  
Pvt Data ◽  
High Shear Rates ◽  
Nanotube Composites ◽  
Multi Walled Carbon Nanotubes ◽  
Time Temperature Superposition Principle ◽  
Increasing Temperature ◽  
Walled Carbon Nanotubes

In this study, capillary rheological tests were performed on polypropylene filled with multi-walled carbon nanotubes (PP/MWCNT) to determine the melt flow curves and pressure-Volume-Temperature (pVT) diagrams. Based on the experimental data, master viscosity curves were constructed using the time-temperature-superposition principle and the Cross and Carreau-Winter models, while the pVT data were fitted to the Tait equation in both liquid and solid states. Results show that the melt shear viscosity decreases with increasing melt temperature and shear rate and increases with MWCNT wt.%. All composites display shear-thinning behavior in the range of medium to high shear rates. The specific volume of PP/MWCNT composite decreases with increasing MWCNT wt.% and pressure and increases with increasing temperature.

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.

Investigation of Structure-Property Relationships in Thermoplastic Polyurethane/Multiwalled Carbon Nanotube Composites

2017 ◽  
Author(s):  
Felicia Stan ◽  
Catalin Fetecau ◽  
Nicoleta V. Stanciu ◽  
Razvan T. Rosculet ◽  
Laurentiu I. Sandu
Keyword(s):  
Electrical Properties ◽  
Shear Viscosity ◽  
Thermoplastic Polyurethane ◽  
Structure Property ◽  
Multiwalled Carbon ◽  
Structure Property Relationships ◽  
Mechanical And Electrical Properties ◽  
High Shear Rates ◽  
Nanotube Composites ◽  
Multi Walled Carbon Nanotubes

In this study, the structure-property relationships in thermoplastic polyurethane (TPU) filled with multi-walled carbon nanotubes (MWCNTs) were investigated. Firstly, the contribution of MWCNTs to the melt shear viscosity and the pressure-volume-temperature (pVT) behavior was investigated. Secondly, injection-molded samples and 2 mm diameter filaments of TPU/MWCNT composites were fabricated and their mechanical and electrical properties analyzed. It was found that the melt processability of TPU/MWCNT composites is not affected by the addition of a small amount (1–5 wt.%) of MWCNTs, all composites displaying shear-thinning at high shear rates. The mechanical and electrical properties of the TPU/MWCNT composites were substantially enhanced with the addition of MWCNTs. However, the conductivity values of composites processed by injection molding were two and three orders of magnitude lower than those of composites processed by extrusion, highlighting the role of melt shear viscosity on the dispersion and agglomeration of nanotubes.

Dynamic Mechanical and Dielectric Properties of Ethylene Vinyl Acetate/Carbon Nanotube Composites

2014 ◽  
Vol 53 (3) ◽  
pp. 496-512 ◽  
Author(s):  
Helena Valentová ◽  
Markéta Ilčíková ◽  
Klaudia Czaniková ◽  
Zdenko Špitalský ◽  
Miroslav Šlouf ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Dielectric Properties ◽  
Vinyl Acetate ◽  
Ethylene Vinyl Acetate ◽  
Dynamic Mechanical ◽  
Nanotube Composites ◽  
Carbon Nanotube Composites

Dynamic electrical properties of polymer-carbon nanotube composites: Enhancement through covalent bonding

2006 ◽  
Vol 21 (4) ◽  
pp. 1071-1077 ◽  
Author(s):  
Seamus A. Curran ◽  
Donghui Zhang ◽  
Wudyalew T. Wondmagegn ◽  
Amanda V. Ellis ◽  
Jiri Cech ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Conductivity Measurement ◽  
Decomposition Temperature ◽  
Composite Formation ◽  
Nanotube Composites ◽  
Multi Walled Carbon Nanotubes ◽  
Charge Hopping ◽  
A New Technique ◽  
Covalently Linked ◽  
Walled Carbon Nanotubes

Composite formation between carbon nanotubes and polymers can dramatically enhance the electrical and thermal properties of the combined materials. We have prepared a composite from polystyrene and multi-walled carbon nanotubes (MWCNT) and, unlike traditional techniques of composite formation, we chose to polymerize styrene from the surface of dithiocarboxylic ester-functionalized MWCNTs to fabricate a unique composite material, a new technique dubbed “gRAFT” polymerization. The thermal stability of the polymer matrix in the covalently linked MWCNT-polystyrene composite is significantly enhanced, as demonstrated by a 15 °C increase of the decomposition temperature than that of the noncovalently linked MWCNT-polystyrene blend. Thin films made from the composite with low MWCNT loadings (<0.9 wt%) are optically transparent, and we see no evidence of aggregation of nanotubes in the thin film or solution. The result from the conductivity measurement as a function of MWCNT loadings suggests two charge transport mechanisms: charge hopping in low MWCNT loadings (0.02–0.6 wt%) and ballistic quantum conduction in high loadings (0.6–0.9 wt%). The composite exhibits dramatically enhanced conductivity up to 33 S m−1 at a low MWCNT loading (0.9 wt%).

Electrospun Polymer/MWCNTs Nanofiber Reinforced Composites “Improvement of Interfacial Bonding by Surface Modified Nanofibers”

2009 ◽  
Vol 1224 ◽  
Author(s):  
Elif Ozden ◽  
Yusuf Ziya Menceloglu ◽  
Melih Papila
Keyword(s):  
Storage Modulus ◽  
Mechanical Response ◽  
Crosslinking Agent ◽  
Weight Fraction ◽  
Crosslinking Density ◽  
Interfacial Bonding ◽  
Reinforced Composites ◽  
Multi Walled Carbon Nanotubes ◽  
Surface Modified ◽  
Walled Carbon Nanotubes

AbstractIn-house synthesized copolymers Polystyrene-co-glycidyl methacrylate (PSt-co-GMA) are electrospun as mat of surface modified nanofibers with and without multi walled carbon nanotubes (MWCNTs). Composites are then formed by embedding layers of the nanofiber mats into epoxy resin. Interfacial bonding between polymer matrix and the nanofibers, and surface modification driven enhancement in mechanical response is assessed under flexural loads. Results indicate that at elevated temperture storage modulus of epoxy reinforced by PSt-co-GMA nanofibers and PSt-co-GMA/ MWCNTs composite nanofibers is about 10 and 20 times higher than the neat epoxy, respectively, despite weight fraction of the nanofibers being as low as 2%. Interfacial interaction is revealed by the storage modulus comparison of unmodified Polystyrene (PSt) and modified PSt-co-GMA nanofiber reinforced composite. To enhance further the resulting “crosslinked” structure, crosslinking agent ethylenediamine is also sprayed on the nanofibrous mats. Increased crosslinking density improves mechanical response of sprayed-over PSt-co-GMA nanofibers reinforced composites which is about 4 times higher than plain PSt-co-GMA nanofibers.

scholarly journals Microstructure Evaluation and Thermal–Mechanical Properties of ABS Matrix Composite Filament Reinforced with Multi-Walled Carbon Nanotubes by a Single Screw Extruder for FDM 3D Printing

2021 ◽  
Vol 11 (19) ◽  
pp. 8798
Author(s):  
Thai-Hung Le ◽  
Van-Son Le ◽  
Quoc-Khanh Dang ◽  
Minh-Thuyet Nguyen ◽  
Trung-Kien Le ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Fused Deposition Modeling ◽  
Acrylonitrile Butadiene Styrene ◽  
Melt Flow Index ◽  
Tensile Tests ◽  
Flow Index ◽  
Fused Deposition ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Composite Filament

This paper reports the synthesis of a new printable ABS–MWCNT composite filament, for use in fused deposition modeling (FDM), using an extrusion technique. Acrylonitrile butadiene styrene (ABS) and multi-walled carbon nanotubes (MWCNTs) were the initial materials used for fabricating the filaments. The MWCNTs were dispersed in ABS resin, then extruded through a single-shaft extruder in filament form, with MWCNT contents of 0.5%, 1%, 1.5%, 2%, 3% or 4% by weight. After extrusion, the diameter of the filaments was about 1.75 mm, making them appropriate for FDM. The as-synthesized filaments were then used in FDM to print out samples, on which tensile tests and other analyses were carried out. The results demonstrate that the sample with 2% MWCNTs had the highest strength value, 44.57 MPa, comprising a 42% increase over that of the pure ABS sample. The morphology and dispersion of MWCNTs in the composite were observed by field emission scanning electron microscopy (FESEM), demonstrating the uniform distribution of MWCNTs in the ABS matrix. The thermal behavior results indicated no significant change in the ABS structure; however, the melt flow index of the filaments decreased with an increase in the MWCNT content.

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