Thermal Conductivity Measurements of Nylon 11-Carbon Nanofiber Nanocomposites

2009 ◽  
Vol 131 (9) ◽  
Author(s):  
Arden L. Moore ◽  
Antonette T. Cummings ◽  
Justin M. Jensen ◽  
Li Shi ◽  
Joseph H. Koo
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanofiber ◽  
Effective Medium Theory ◽  
Twin Screw Extrusion ◽  
Medium Theory ◽  
Interface Thermal Resistance ◽  
Screw Extrusion ◽  
The Matrix ◽  
Twin Screw ◽  
Nylon 11

Carbon nanofibers (CNFs) were incorporated into nylon 11 to form nylon 11-carbon nanofiber nanocomposites via twin screw extrusion. Injection molding has been employed to fabricate specimens that possess enhanced mechanical strength and fire retardancy. The thermal conductivity of these polymer nanocomposites was measured using a guarded hot plate method. The measurement results show that the room temperature thermal conductivity increases with the CNF loading from 0.24±0.01 W/m K for pure Nylon 11 to 0.30±0.02 W/m K at 7.5 wt % CNF loading. The effective medium theory has been used to determine the interface thermal resistance between the CNFs and the matrix to be in the range of 2.5–5.0×10−6 m2 K/W from the measured thermal conductivity of the nanocomposite.

Flame-retardant polyamide 11 nanocomposites: further thermal and flammability studies

2011 ◽  
Vol 29 (6) ◽  
pp. 479-498 ◽  
Author(s):  
S. C. Lao ◽  
J. H. Koo ◽  
T. J. Moon ◽  
M. Londa ◽  
C. C. Ibeh ◽  
...  
Keyword(s):  
Flame Retardant ◽  
Twin Screw Extrusion ◽  
Cone Calorimetry ◽  
Polyamide 11 ◽  
Polymer Systems ◽  
Low Concentrations ◽  
Screw Extrusion ◽  
Twin Screw ◽  
Nylon 11 ◽  
Ul 94

Polyamide (nylon) 11 (PA11) were melt-blended by dispersing low concentrations of nanoparticles (NPs), namely nanoclays (NCs) and carbon nanofibers (CNFs) via twin-screw extrusion. To enhance their thermal and flame retardant (FR) properties, an intumescent FR additive was added to the mechanically superior NC and CNF PA11 formulations. For neat and NP-reinforced PA11 as well as for PA11 reinforced by both intumescent FR and select NPs (NC or CNF), decomposition temperatures by TGA, flammability properties by UL 94, and cone calorimetry values were measured. All PA11 polymer systems infused with both NPs and FR additive had higher decomposition temperatures than those infused with solely FR additive. For the PA11/FR/NC polymer blends, Exolit® OP 1312 (FR2) is the preferred FR additive to pass the UL 94 V-0 requirement with 20 wt%. For the PA11/FR/CNF formulations, all Exolit® OP 1311 (FR1), OP 1312 (FR2), and OP 1230 (FR3) FR additives passed the UL 94 V-0 requirement with 20 wt%.

Research on Processing Technology Product Design and the Application of Nano-Wood-Plastic Composite Materials

2020 ◽  
Vol 20 (12) ◽  
pp. 7787-7792
Author(s):  
Xin Fang ◽  
Jinjin Rong ◽  
Yilin Deng ◽  
Moon-Hwan Jee
Keyword(s):  
Mechanical Properties ◽  
Wood Plastic Composite ◽  
Twin Screw Extrusion ◽  
Cross Sectional ◽  
Plastic Composite ◽  
Screw Extrusion ◽  
Different Types ◽  
The Matrix ◽  
Twin Screw ◽  
Treatment Agent

This study focused on the design of wood-plastic composite (WPC) products. In this study, recycled high-density polyethylene plastic was used as the matrix, wood powder was used as the filler, different types of nanofillers and self-synthesized nanofiller treatment agents were added, and the twin-screw extrusion granulation method was used to prepare nano-WPC materials. The effects of different types of nanofillers on the mechanical properties of nano-WPC materials were investigated, and the cross-sectional structures of the materials were analyzed by scanning electron microscopy. The results showed that nanofiller treatment agents improved the interface compatibility of the materials. When the treatment agent content reached 2.5% and the nano-montmorillonite content reached 10%, the mechanical properties of the material reach their maximum values.

scholarly journals Process-Induced Fiber Orientation in Fused Filament Fabrication

2018 ◽  
Vol 2 (3) ◽  
pp. 45 ◽  
Author(s):  
Tom Mulholland ◽  
Sebastian Goris ◽  
Jake Boxleitner ◽  
Tim Osswald ◽  
Natalie Rudolph
Keyword(s):  
Thermal Conductivity ◽  
Fiber Orientation ◽  
Polyamide 6 ◽  
Thermoplastic Composite ◽  
Micro Computed Tomography ◽  
Twin Screw Extrusion ◽  
Fused Filament Fabrication ◽  
Screw Extrusion ◽  
Twin Screw ◽  
Thin Walled

As the applications for additive manufacturing have continued to grow, so too has the range of available materials, with more functional or better performing materials constantly under development. This work characterizes a copper-filled polyamide 6 (PA6) thermoplastic composite designed to enhance the thermal conductivity of fused filament fabrication (FFF) parts, especially for heat transfer applications. The composite was mixed and extruded into filament using twin screw extrusion. Because the fiber orientation within the material governs the thermal conductivity of the material, the orientation was measured in the filament, through the nozzle, and in printed parts using micro-computed tomography. The thermal conductivity of the material was measured and achieved 4.95, 2.38, and 0.75 W/(m·K) at 70 °C in the inflow, crossflow, and thickness directions, respectively. The implications of this anisotropy are discussed using the example of an air-to-water crossflow heat exchanger. The lower conductivity in the crossflow direction reduces thermal performance due to the orientation in thin-walled parts.

Influence of the polarity of the matrix on the breakage mechanisms of lignocellulosic fibers during twin‐screw extrusion

2019 ◽  
Vol 41 (3) ◽  
pp. 1106-1117 ◽  
Author(s):  
Françoise Berzin ◽  
Loubna Lemkhanter ◽  
Carlos Marcuello ◽  
Brigitte Chabbert ◽  
Véronique Aguié‐Béghin ◽  
...  
Keyword(s):  
Twin Screw Extrusion ◽  
Lignocellulosic Fibers ◽  
Screw Extrusion ◽  
The Matrix ◽  
Twin Screw

Correlation of Rheological and Electrical Percolation in PVDF-MWNT Nanocomposites

2013 ◽  
Author(s):  
Reza Rizvi ◽  
Hani Naguib
Keyword(s):  
Electrical Conductivity ◽  
Filler Particle ◽  
Multiwall Carbon Nanotubes ◽  
Twin Screw Extrusion ◽  
Electrical Percolation ◽  
Percolation Behavior ◽  
Screw Extrusion ◽  
The Matrix ◽  
Twin Screw ◽  
And Storage

This study investigates the evolution of filler particle networks using electrical and rheological property measurements. Polyvinylediene Flouride (PVDF) was used as the matrix thermoplastic polymer which was reinforced with multiwall carbon nanotubes (MWNT) as the filler phase using high shear twin screw extrusion mixing. Electrical conductivity and dielectric constant measurements were done using impedance spectroscopy. Viscosity and storage modulus measurements were performed using a dynamic rheometer. Morphologies of the composites were observed using scanning electron microscopy. The percolation behavior in electrical conductivity was determined to be 1.3 wt% MWNT content in PVDF. This is in contrast to the nanocomposite viscosity percolation threshold which occurred at 1.9 wt%.

The Effect of Molding Process and Test Conditions on the Thermal Conductivity of Polypropylene/Graphite Composites

2012 ◽  
Vol 588-589 ◽  
pp. 1702-1708
Author(s):  
Sha Yan ◽  
Ying Liu ◽  
Da Ming Wu ◽  
Hui Lin Yuan
Keyword(s):  
Thermal Conductivity ◽  
Twin Screw Extrusion ◽  
Molding Process ◽  
Injection Speed ◽  
Melt Index ◽  
Conductive Composites ◽  
Screw Extrusion ◽  
Twin Screw ◽  
Lower Temperature ◽  
Graphite Composites

The thermal conductive composites prepared by twin-screw extrusion extrudes polypropylene and graphite.This paper studies the influence of molding process on the thermal conductivity.The experimental results show that thermal conductivity of composites changes with the screw rotate speed changing,obtaining the maximum when the screw rotate speed is 300r/min.Results indicate that the opposite trend with thermal conductivity and the melt index and injection speed,and the injection temperature has not a big influence on the thermal conductivity. The crystallization influences the electrical conductivity and density of some points of molding samples.In addition,the test condition has cast impact on thermal conductivity,in the lower temperature(lower than the Debye temperature),the thermal conductivity of composites increased with the of temperature and humidity increasing.

scholarly journals In-Line Rheo-Optical Investigation of the Dispersion of Organoclay in a Polymer Matrix during Twin-Screw Compounding

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2128
Author(s):  
Paulo F. Teixeira ◽  
José A. Covas ◽  
Loïc Hilliou
Keyword(s):  
Local Heating ◽  
Polymer Nanocomposite ◽  
Structural Rearrangement ◽  
Particle Dispersion ◽  
Optical Investigation ◽  
Twin Screw Extrusion ◽  
Clay Particles ◽  
Clay Dispersion ◽  
Screw Extrusion ◽  
Twin Screw

The dispersion mechanisms in a clay-based polymer nanocomposite (CPNC) during twin-screw extrusion are studied by in-situ rheo-optical techniques, which relate the CPNC morphology with its viscosity. This methodology avoids the problems associated with post extrusion structural rearrangement. The polydimethylsiloxane (PDMS) matrix, which can be processed at ambient and low temperatures, is used to bypass any issues associated with thermal degradation. Local heating in the first part of the extruder allows testing of the usefulness of low matrix viscosity to enhance polymer intercalation before applying larger stresses for clay dispersion. The comparison of clay particle sizes measured in line with models for the kinetics of particle dispersion indicates that larger screw speeds promote the break-up of clay particles, whereas smaller screw speeds favor the erosion of the clay tactoids. Thus, different levels of clay dispersion are generated, which do not simply relate to a progressively better PDMS intercalation and higher clay exfoliation as screw speed is increased. Reducing the PDMS viscosity in the first mixing zone of the screw facilitates dispersion at lower screw speeds, but a complex interplay between stresses and residence times at larger screw speeds is observed. More importantly, the results underline that the use of larger stresses is inefficient per se in dispersing clay if sufficient time is not given for PDMS to intercalate the clay galleries and thus facilitate tactoid disruption or erosion.

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