scholarly journals Rheology and 3D Printability of Percolated Graphene–Polyamide-6 Composites

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2014
Author(s):  
Kok Peng Marcian Lee ◽  
Milan Brandt ◽  
Robert Shanks ◽  
Fugen Daver
Keyword(s):  
Complex Viscosity ◽  
Polyamide 6 ◽  
Steady Shear ◽  
Melt Mixing ◽  
Capillary Rheometry ◽  
Shear Rates ◽  
Oscillatory Rheometry ◽  
Flow Through ◽  
Graphene Content ◽  
Fundamental Equations

Graphene–polyamide-6 (PA6) composites with up to 17.0%·w/w graphene content were prepared via melt mixing. Oscillatory rheometry revealed that the dynamic viscoelastic properties of PA6 decreased with the addition of 0.1%·w/w graphene but increased when the graphene content was increased to 6.0%·w/w and higher. Further analysis indicated that the rheological percolation threshold was between 6.0 and 10.0%·w/w graphene. The Carreau–Yasuda model was used to describe the complex viscosity of the materials. Capillary rheometry was applied to assess the steady shear rheology of neat PA6 and the 17.0%·w/w graphene–PA6 composite. High material viscosity at low shear rates coupled with intense shear-thinning in the composite highlighted the importance of selecting the appropriate rheological characterisation methods, shear rates and rheological models when assessing the 3D printability of percolated graphene–polymer composites for material extrusion (ME). A method to predict the printability of an ME filament feedstock, based on fundamental equations describing material flow through the printer nozzle, in the form of a printing envelope, was developed and verified experimentally. It was found that designing filaments with steady shear viscosities of approximately 15% of the maximum printable viscosity for the desired printing conditions will be advantageous for easy ME processing.

Capillary Rheometry of Carbon-Black-Filled Butadiene—Acrylonitrile Copolymers

1975 ◽  
Vol 48 (4) ◽  
pp. 615-622 ◽  
Author(s):  
N. Nakajima ◽  
E. A. Collins
Keyword(s):  
Shear Rate ◽  
Carbon Black ◽  
Tensile Stress ◽  
Capillary Flow ◽  
Complex Viscosity ◽  
Appreciable Effect ◽  
Stress Strain ◽  
Capillary Rheometry ◽  
Strain Behavior ◽  
Acrylonitrile Copolymers

Abstract Capillary rheometry of carbon-black-filled butadiene—acrylonitrile copolymers at 125°C was performed over a wide shear rate range. The data were corrected for pressure loss in the barrel and at the capillary entrance, and for the non-Newtonian velocity profile (Rabinowitsch correction). No appreciable effect of pressure on viscosity was observed. The die swell values were very small, 1.1–1.4. This fact and the shape of the plots of shear stress vs. shear rate imply the presence of a particulate structure, which is probably built by carbon black surrounded with bound rubber. Unlike the behavior of raw amorphous elastomers, the steady-shear viscosity, the dynamic complex viscosity, and the viscosity calculated from tensile stress-strain behavior were significantly different from each other. That is, the capillary flow data indicated an alteration of the structure towards strain softening, and the tensile stress-strain behavior showed strain hardening, indicating retention of the structure up to the yield point. In the dynamic measurement, being conducted at very small strain, the structure is least disturbed. With unfilled elastomers essentially the same deformational mechanism was believed to be responsible in these three measurements, because the results can be expressed by a single master curve.

Capillary RheoSANS: measuring the rheology and nanostructure of complex fluids at high shear rates

Soft Matter ◽  
2020 ◽  
Vol 16 (27) ◽  
pp. 6285-6293
Author(s):  
Ryan P. Murphy ◽  
Zachary W. Riedel ◽  
Marshall A. Nakatani ◽  
Paul F. Salipante ◽  
Javen S. Weston ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Complex Fluids ◽  
Inorganic Nanoparticles ◽  
High Shear ◽  
Capillary Rheometry ◽  
Shear Rates ◽  
High Shear Rates

Capillary rheometry is combined with small-angle neutron scattering to simultaneously measure the viscosity and nanostructure of complex fluids containing proteins, surfactants, polymers, and inorganic nanoparticles at shear rates up to 106 s−1.

scholarly journals Characterization of Polyamide 6/Multilayer Graphene Nanoplatelet Composite Textile Filaments Obtained Via In Situ Polymerization and Melt Spinning

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1787
Author(s):  
Jelena Vasiljević ◽  
Andrej Demšar ◽  
Mirjam Leskovšek ◽  
Barbara Simončič ◽  
Nataša Čelan Korošin ◽  
...  
Keyword(s):  
Melt Spinning ◽  
In Situ Polymerization ◽  
Complex Viscosity ◽  
Polyamide 6 ◽  
High Dispersion ◽  
Multilayer Graphene ◽  
Main Challenge ◽  
Dispersion State ◽  
Continuous Filament

Studies of the production of fiber-forming polyamide 6 (PA6)/graphene composite material and melt-spun textile fibers are scarce, but research to date reveals that achieving the high dispersion state of graphene is the main challenge to nanocomposite production. Considering the significant progress made in the industrial mass production of graphene nanoplatelets (GnPs), this study explored the feasibility of production of PA6/GnPs composite fibers using the commercially available few-layer GnPs. To this aim, the GnPs were pre-dispersed in molten ε-caprolactam at concentrations equal to 1 and 2 wt %, and incorporated into the PA6 matrix by the in situ water-catalyzed ring-opening polymerization of ε-caprolactam, which was followed by melt spinning. The results showed that the incorporated GnPs did not markedly influence the melting temperature of PA6 but affected the crystallization temperature, fiber bulk structure, crystallinity, and mechanical properties. Furthermore, GnPs increased the PA6 complex viscosity, which resulted in the need to adjust the parameters of melt spinning to enable continuous filament production. Although the incorporation of GnPs did not provide a reinforcing effect of PA6 fibers and reduced fiber tensile properties, the thermal stability of the PA6 fiber increased. The increased melt viscosity and graphene anti-dripping properties postponed melt dripping in the vertical flame spread test, which consequently prolonged burning within the samples.

scholarly journals Relaxation Dynamics in Polyethylene Glycol/Modified Hydrotalcite Nanocomposites

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1182 ◽  
Author(s):  
Rossella Arrigo ◽  
Diego Antonioli ◽  
Massimo Lazzari ◽  
Valentina Gianotti ◽  
Michele Laus ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Polymer Matrix ◽  
Complex Viscosity ◽  
Gas Chromatography Mass Spectrometry ◽  
Hydroxyl Groups ◽  
Thermal Treatments ◽  
Relaxation Dynamics ◽  
Unusual Behavior ◽  
Melt Mixing ◽  
Grafting Reactions

Polyethylene glycol-based nanocomposites containing an organo-modified hydrotalcite with loadings ranging from 0.5 to 5 wt.% were prepared by melt mixing performed just above the melting point of the polymer matrix. In these conditions, the dispersion of the nanofiller within the polymer matrix was quite homogeneous as revealed by TEM analyses. The effect of various thermal treatments and filler loadings was thoroughly investigated by means of rheological, morphological and gas chromatography-mass spectrometry, hyphenated to thermogravimetry analysis tests. Unfilled polyethylene glycol exhibited a continuous decrease in complex viscosity upon heating. In contrast, the complex viscosity of nanocomposites containing nanofiller loadings higher than 1 wt.% showed first a decrease, followed by an increase in the complex viscosity as the temperature increases, exhibiting a minimum between 130 and 140 °C. Annealing at 180 °C for different times further increased the viscosity of the system. This unusual behavior was explained by the occurrence of grafting reactions between the –OH terminal groups of the polyethylene glycol chains and the hydroxyl groups of the organo-modified filler, thus remarkably affecting the relaxation dynamics of the system.

scholarly journals Mechanical properties of carbon monoxide reduced graphene–polyamide-6 nanocomposites prepared by melt-mixing

2019 ◽  
Author(s):  
Kok Peng Marcian Lee ◽  
Michael Czajka ◽  
Robert Shanks ◽  
Fugen Daver
Keyword(s):  
Mechanical Properties ◽  
Carbon Monoxide ◽  
Polyamide 6 ◽  
Melt Mixing ◽  
Reduced Graphene

Characterization of Fabricated Feedstock Using Nano Powders and a Water-Soluble Binder in Micro Metal Injection Molding

2013 ◽  
Vol 25 ◽  
pp. 174-180
Author(s):  
Rajabi Javad ◽  
Norhamidi Muhamad ◽  
Abu Bakar Sulong ◽  
Aziz Hasyimah ◽  
Abdolali Fayyaz ◽  
...  
Keyword(s):  
Injection Molding ◽  
Water Soluble ◽  
Metal Injection Molding ◽  
Small Scale ◽  
Powder Size ◽  
Capillary Rheometry ◽  
Shear Rates ◽  
Different Temperatures ◽  
A Minor ◽  
Stainless Steel 316

Micro metal injection molding has become the promising method in powder metallurgy research in order to fabricate small-scale intricate parts in an influential process and competitive cost of mass production. Stainless steel 316 L powders with powder size of 150 nm and 5 μm were mixed with a binder with a water soluble component which consisted of a major fraction of water soluble Polyethylene Glycol (PEG), a minor fraction of polymethyl-methacrylate (PMMA) and some stearic acid has been used as a surfactant. This work aims to investigate the rheological properties of a feedstock which are efficiently characterised by capillary Rheometry to measure apparent viscosities at different temperatures and shear rates. Results obtained by the varying feedstock characteristics, when viscosity decreases by increasing of shear rate at certain temperature feedstock should have a pseudoplastic behaviour. Melt viscosity of the feedstock was decreased by adding nanoscale powders. The reduced (n) values at high temperature with addition of nanoparticles indicated a possible increase in the shear-thinning behavior.

scholarly journals Effect of Graphene Nanosheets on the Morphology, Crystallinity, and Thermal and Electrical Properties of Super Tough Polyamide 6 Using SEBS Compounds

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Farzaneh Alirezaei Hoor ◽  
Jalil Morshedian ◽  
Shervin Ahmadi ◽  
Mohammad Rakhshanfar ◽  
Alireza Bahramzadeh
Keyword(s):  
Electrical Properties ◽  
Carbon Black ◽  
Graphene Nanosheets ◽  
Polyamide 6 ◽  
Melt Mixing ◽  
Graphene Nanocomposites ◽  
Melt Compounding ◽  
Carbon Structures ◽  
Thermal And Electrical Properties ◽  
Amine Groups

Super tough polyamide 6 was prepared by using SEBS and effect of SEBS-g-MA as a compatibilizer of PA6/SEBS matrix on mechanical properties was investigated. Thus super tough polyamide 6/graphene nanocomposites were produced using graphene nanosheets (GNs) through the melt compounding method. To compare the effectiveness of graphene, effects of graphite and carbon black (the other carbon structures) are also studied on the same matrix. The effects of graphene on crystallinity, improvements of morphology, and thermal and electrical properties of the nanocomposites were researched and compared with similar samples of graphite and carbon black. Due to the reaction between the maleic anhydride groups of SEBS and amine groups of nylon chains during the melt mixing process, super tough polyamide 6 was produced with high impact and tensile strength. The most important results of this study can be noted as an increase in the electrical conductivity and thermal stability by adding graphene to PA6/SEBS blend. Also the effect of graphene compatibility on PA6/SEBS/SEBS-g-MA blend was investigated with studying morphology.

Electrical and rheological properties of carbon black and carbon fiber filled low-density polyethylene/ethylene vinyl acetate composites

2018 ◽  
Vol 25 (4) ◽  
pp. 715-723 ◽  
Author(s):  
Xingchi Xu ◽  
Tingwei Wang
Keyword(s):  
Carbon Fiber ◽  
Carbon Black ◽  
Vinyl Acetate ◽  
Great Influence ◽  
Complex Viscosity ◽  
Ethylene Vinyl Acetate ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Melt Mixing ◽  
Significant Difference

Abstract In this study conductive composites of low-density polyethylene (LDPE)/ethylene-vinyl acetate (EVA) filled with carbon black (CB) and carbon fiber (CF) were prepared by melt-mixing method. The morphological, rheological, and electrical properties of CB filled composites were compared with CF filled composites by digital multimeter, scanning electron microscope, rotational rheometer, etc. The composites filled with different fillers have same percolation threshold but the EVA concentration has different effect on the two systems. For CB filled composites the increase in EVA concentration decreased resistivity first and reached lowest point when the LDPE:EVA ratio was 70:30; then the resistivity increased, but for CF filled composites the resistivity continued to decrease. The differences were caused by the diverse morphological and filler distribution of two different composite systems. The rheological behaviors of two types of composites also had significant difference; the value of complex viscosity of CB filled composites was about two orders of magnitude more than CF filled composites in low frequency region. It was because CB particles was nano-scale and had large surface area, so it had great influence on the value of complex viscosity of composites.

Effects of 3-APTMS-Modified Nano-SiO2 on the Mechanical Properties and Crystallization Behavior of Polyamide-6

2016 ◽  
Vol 869 ◽  
pp. 314-319
Author(s):  
Breno D. Queiroz ◽  
Vitor L.P. Janzantti ◽  
José Donato Ambrósio
Keyword(s):  
Residence Time ◽  
Rotational Speed ◽  
Polyamide 6 ◽  
Processing Parameters ◽  
Solution Viscosity ◽  
Mechanical And Thermal Properties ◽  
Melt Blending ◽  
Scanning Calorimetry ◽  
Capillary Rheometry ◽  
Filling Volume

Nanocomposites of polyamide-6 with nanoSiO2 surface modified by 3-aminopropyltrimethoxysilane (3-APTMS) were prepared by melt blending in torque rheometer. Chemical modification of nanoparticles surface with 3-APTMS were observed by FTIR. Prior to nanocomposites processing, neat polyamide-6 (PA-6) was processed in a torque rheometer with varying processing parameters: polymer residence time in the chamber, rollers rotational speed, and polymer filling volume in the chamber. Two levels for each parameter were fixed. The influence of these parameters on degradation of PA-6 was determined by dilute solution viscosity and capillary rheometry. Results indicate that the best condition was achieved with the higher polymer residence time in the chamber, the higher rollers rotational speed, and the higher polymer filling volume in the chamber. With this information, PA-6 pellets were mixed with nanosilica particles unmodified and surface-capped by 3-APTMS via melt blending in torque rheometer, obtaining PA-6 composites with 1 wt.% of nanofillers. Mechanical and thermal properties of nanocomposites were evaluated by means of tensile test and differential scanning calorimetry (DSC).

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