Polymer blends of carboxylated butadiene-acrylonitrile copolymer (nitrile rubber) and polyamide 6 developed in twin screw extrusion

2007 ◽  
Vol 104 (1) ◽  
pp. 372-377 ◽  
Author(s):  
Rajesh Chowdhury ◽  
M. S. Banerji ◽  
K. Shivakumar
Keyword(s):  
Polymer Blends ◽  
Polyamide 6 ◽  
Nitrile Rubber ◽  
Twin Screw Extrusion ◽  
Acrylonitrile Copolymer ◽  
Screw Extrusion ◽  
Twin Screw

Self-Extinguishing and Non-Drip Flame Retardant Polyamide 6 Nanocomposite: Mechanical, Thermal, and Combustion Behavior

2018 ◽  
Vol 1 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Hao Wu ◽  
Rogelio Ortiz ◽  
Renan De Azevedo Correa ◽  
Mourad Krifa ◽  
Joseph H. Koo
Keyword(s):  
Maleic Anhydride ◽  
Flame Retardant ◽  
Polymer Matrix ◽  
Flame Retardants ◽  
Polyamide 6 ◽  
Twin Screw Extrusion ◽  
Elongation At Break ◽  
Combustion Behavior ◽  
Screw Extrusion ◽  
Twin Screw

AbstractIncorporation of flame-retardant (FR) additives and nanoclay fillers into thermoplastic polymers effectively suppresses materials flammability and melt dripping behavior. However, it largely affects other properties, such as toughness and ductility. In order to recover the lost toughness and ductility of flame retardant polyamide 6, various loadings of maleic anhydride modified SEBS elastomer were added and processed by twin screw extrusion. TEM images showed exfoliated nanoclay platelets and reveals that the clay platelets well dispersed in the polymer matrix. By balancing the ratio of flame retardants, nanoclay and elastomers, formulation with elongation at break as high as 76% was achieved. Combining conventional intumescent FR and nanoclay, UL-94 V-0 rating and the LOI value as high as 32.2 were achieved. In conclusion, effective self-extinguishing and non-drip polyamide 6 nanocomposite formulations with significant improvement in toughness and ductility were achieved.

scholarly journals Rheological characterization of polymer-based nanocomposites with different nanoscale dispersions

e-Polymers ◽  
2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Dong Gi Seong ◽  
Tae Jin Kang ◽  
Jae Ryoun Youn
Keyword(s):  
Storage Modulus ◽  
Extensional Flow ◽  
Rheological Behaviour ◽  
Polyamide 6 ◽  
Twin Screw Extrusion ◽  
Rheological Characterization ◽  
Melt Compounding ◽  
Transmission Electron ◽  
Screw Extrusion ◽  
Twin Screw

AbstractPolyamide 6 - clay nanocomposites with different nanoscale dispersions were prepared by melt compounding via twin-screw extrusion and their internal structures were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The rheological behaviour of these nanocomposites in shear and extensional flow were investigated using an Advanced Rheometric Expansion System and an Elongational Melts Rheometer in connection with the analysis by XRD and TEM. Nanocomposites with fully exfoliated structure and with poorly dispersed structure showed very different rheological behaviour. In general, addition of clay increased the viscosity and the storage modulus of nanocomposites, but different rheological behaviours were observed depending upon the degree of clay dispersion in the polymer matrix. In shear flow, only the exfoliated nanocomposite showed solid-like plateau behaviour in storage modulus and strong shear-thinning behaviour in shear viscosity. In extensional flow, only fully exfoliated nanocomposites showed strain-hardening behaviour, which is caused by the interaction between nanoparticles as well as between polymer molecules and nanoparticles.

Preparation of Polypropylene Graft Maleic Anhydride (PP-g-MA) via Twin Screw Extrusion

2010 ◽  
Vol 93-94 ◽  
pp. 451-454 ◽  
Author(s):  
Rittirong Pruthtikul ◽  
Pitcha Liewchirakorn
Keyword(s):  
Maleic Anhydride ◽  
Polyamide 6 ◽  
Standard Test ◽  
Acid Number ◽  
Test Method ◽  
Reactive Blending ◽  
Twin Screw Extrusion ◽  
Screw Extrusion ◽  
Twin Screw ◽  
Izod Impact

Polypropylene (PP) samples grafted with Maleic Anhydride (MA) were prepared by reactive blending via co-rotating twin screw extrusion. The PP was functionalized in the presence of an optimized amount of precursor, Dicumyl Peroxide (DCP) and MA. The amounts of MA grafted on PP were checked by standard test method for acid number. Maleated PP as a compatibilizer with the highest acid number was added to PP/Polyamide 6 (PA6) and blended in the twin screw extrusion. It was found that the PP-g-MA enhanced tensile properties as well as the izod impact properties of notched samples of PP/PA6/PP-g-MA blends compared to neat polypropylene. The scanning electron microscope confirmed the good adhesion of PA6 on PP matrix.

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.

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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