scholarly journals Improving the Oxygen Barrier of Polyamide Food Packaging by Using Nanoclay

2021 ◽  
Author(s):  
Tonis PAARA ◽  
Sven LANGE ◽  
Kristjan SAAL ◽  
Rünno LÕHMUS ◽  
Andres KRUMME ◽  
...  
Keyword(s):  
Food Packaging ◽  
Transmission Rate ◽  
Low Cost ◽  
Twin Screw Extrusion ◽  
Oxygen Transmission Rate ◽  
Industrial Grade ◽  
Screw Extrusion ◽  
Twin Screw ◽  
Polyamide Film ◽  
Film Making

The effect of nanoclay additive on polyamide film oxygen permeability is investigated from the perspective of possible use as a laminate component for low-cost food packaging material. Montmorillonite nanoclay was melt-mixed in an industrial grade polyamide by twin-screw extrusion and the mixture was hot-pressed to a ~50 µm thick film. The film with 10 wt.% of nanoclay loading showed a 17 % decrease in the oxygen transmission rate (OTR), as compared to the pristine polyamide film (72 and 87 cm3/m2∙24 h, respectively). Despite the relatively high loading of the filler the obtained OTR exceeds that of the food packaging preferred upper limit of 10 cm3/m2∙24 h. XRD measurements confirmed the near-complete exfoliation of the nanoclay platelets. The platelets were found to be at an average angle of 9.5 degrees relative to the film’s surface plane. To comply with the requirements for food packaging, this angle needs to be decreased down to 0.4 degrees. To achieve this, different film-making methods enabling better control over the filler particles’ orientation need to be explored. Nanoclay addition increased the films’ yield strength (23 % for 10 wt.% film) and stiffness, while not affecting the films’ optical appearance.

scholarly journals Investigations for In-house prepared Biocompatible Feed Stock Filament of Fused Deposition Modelling: A Process Capability study

2019 ◽  
Vol 48 (1) ◽  
pp. 18-23
Author(s):  
Nishant Ranjan ◽  
Rupinder Singh ◽  
IPS Ahuja
Keyword(s):  
Control Charts ◽  
Low Cost ◽  
Process Capability ◽  
Dimensional Accuracy ◽  
Fused Deposition Modelling ◽  
Twin Screw Extrusion ◽  
Fused Deposition ◽  
Feed Stock ◽  
Screw Extrusion ◽  
Twin Screw

Fused deposition modelling (FDM) is one of the low cost additive manufacturing (AM) process. The feed stock filament of FDM is the only consumable in the process and by preparing (in-house) bio compatible feed stock filament the application domain can be increased. Some studies have reported the use of twin screw extrusion (TSE) process for preparation of bio compatible feed stock filament (comprising of polyvinyl chloride (PVC) and polypropylene (PP) and hydroxyapatite (HAp) particles) with improved mechanical, dimensional and thermal properties, for commercial FDM setup. But hitherto very less has been reported on process capability of in-house prepared biocompatible feed stock filament. In the present work statistical analysis (for tensile strength, hardness and dimensional accuracy) has been performed for investigations of process capability. The results have been also supported by control charts (X-chart and R-chart) based upon the best feedstock filament wire.

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.

Definition of a JA-2 Equivalent Propellant to be Produced by Continuous Solventless Extrusion

2013 ◽  
Vol 80 (3) ◽  
Author(s):  
Thelma G. Manning ◽  
Joseph Leone ◽  
Martijn Zebregs ◽  
Dinesh R. Ramlal ◽  
Chris A. van Driel
Keyword(s):  
Extrusion Process ◽  
Continuous Manufacturing ◽  
Twin Screw Extrusion ◽  
Extrusion Processing ◽  
Roll Mill ◽  
Screw Extrusion ◽  
Twin Screw ◽  
Ballistic Properties ◽  
Definition Of ◽  
Double Base

In order to eliminate residual solvents in ammunition and to reduce the emissions of volatile organic compounds to the atmosphere, the U.S. Army ARDEC has teamed with TNO in developing a new process for the production of solventless propellant for tank ammunition. To reduce the costs of solventless propellants production, shear roll mill and continuous extrusion processing was investigated. As described in this paper JA-2 a double base propellant cannot be processed without solvent by the extrusion process. An alternative JA-2 equivalent propellant was defined. The aim of this work is to demonstrate the manufacturing of this propellant by solventless continuous twin screw extrusion processing while maintaining gun performance characteristics of conventional JA-2 propellant. This is elucidated by explicitly researching the relationship between interior ballistic properties of the gun propellant and utilizing a continuous manufacturing process. Processing conditions were established, and the propellant was manufactured accordingly. The extruded propellant has the desired properties, which resulted in a comparable gun performance as the conventional JA-2 propellant.

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