Preparation of Polyethylene and Ethylene/Methacrylic Acid Copolymer Blend Films with Tunable Surface Properties through Manipulating Processing Parameters during Film Blowing

Polymer films based on polyethylene (PE) and ionomer ethylene/methacrylic acid (EMAA) copolymer blend were prepared by film blowing, whose surface properties were tuned by varying processing parameters, i.e., take up ratio (TUR). Blends of PE/EMAA copolymer were firstly prepared by the melt-mixing method, before being further blown to films. The wettability of the film was investigated by measuring the contact angle/water-film encounter time, and optical properties, i.e., the haze and transmittance. The wettability was found to be enhanced with the increase of TUR. So too was the haze, while the transmittance was found to be almost independent of TUR. The XPS and AFM results directly show the increasing polar functional groups (–COO−) on the surface and roughness with increasing TUR. Further analysis of the 2D SAXS and WAXS unveiled the origin of the invariant transmittance, which resulted from the minor change of the crystallinity and the monotonic increase of the haze, with TUR resulting from the evolution of crystal orientation. In addition to other post-modification methods, the current study provides an alternative route to prepare large-scale PE films as the template for the advanced potential applications, i.e., covering in the layer of roof, the privacy of protective windows, and multitudes of packaging.

Download Full-text

Near-unity broadband omnidirectional emissivity via femtosecond laser surface processing

Communications Materials ◽

10.1038/s43246-021-00139-w ◽

2021 ◽

Vol 2 (1) ◽

Author(s):

Andrew Reicks ◽

Alfred Tsubaki ◽

Mark Anderson ◽

Jace Wieseler ◽

Larousse Khosravi Khorashad ◽

...

Keyword(s):

Femtosecond Laser ◽

Surface Properties ◽

Large Scale ◽

Low Cost ◽

Processing Parameters ◽

Laser Surface ◽

Metallic Surfaces ◽

Surface Processing ◽

Perfect Absorption ◽

Distinct Features

AbstractIt is very challenging to achieve near perfect absorption or emission that is both broadband and omnidirectional while utilizing a scalable fabrication process. Femtosecond laser surface processing is an emerging low-cost and large-scale manufacturing technique used to directly and permanently modify the surface properties of a material. The versatility of this technique to produce tailored surface properties has resulted in a rapidly growing number of applications. Here, we demonstrate near perfect, broadband, omnidirectional emissivity from aluminum surfaces by tuning the laser surface processing parameters including fluence, pulse count, and the ambient gas. Full-wave simulations and experimental results prove that the obtained increase in emissivity is mainly a result of two distinct features produced by femtosecond laser surface processing: the introduction of microscale surface features and the thick oxide layer. This technique leads to functionalized metallic surfaces that are ideal for emerging applications, such as passive radiative cooling and thermal management of spacecraft.

Download Full-text

Rapid Single Image-Based DTM Estimation from ExoMars TGO CaSSIS Images Using Generative Adversarial U-Nets

Remote Sensing ◽

10.3390/rs13152877 ◽

2021 ◽

Vol 13 (15) ◽

pp. 2877

Author(s):

Yu Tao ◽

Siting Xiong ◽

Susan J. Conway ◽

Jan-Peter Muller ◽

Anthony Guimpier ◽

...

Keyword(s):

High Resolution ◽

Large Scale ◽

Imaging System ◽

Landing Site ◽

Parameter Tuning ◽

Processing Parameters ◽

Input Image ◽

Large Area ◽

Laser Altimeter ◽

Imaging Science

The lack of adequate stereo coverage and where available, lengthy processing time, various artefacts, and unsatisfactory quality and complexity of automating the selection of the best set of processing parameters, have long been big barriers for large-area planetary 3D mapping. In this paper, we propose a deep learning-based solution, called MADNet (Multi-scale generative Adversarial u-net with Dense convolutional and up-projection blocks), that avoids or resolves all of the above issues. We demonstrate the wide applicability of this technique with the ExoMars Trace Gas Orbiter Colour and Stereo Surface Imaging System (CaSSIS) 4.6 m/pixel images on Mars. Only a single input image and a coarse global 3D reference are required, without knowing any camera models or imaging parameters, to produce high-quality and high-resolution full-strip Digital Terrain Models (DTMs) in a few seconds. In this paper, we discuss technical details of the MADNet system and provide detailed comparisons and assessments of the results. The resultant MADNet 8 m/pixel CaSSIS DTMs are qualitatively very similar to the 1 m/pixel HiRISE DTMs. The resultant MADNet CaSSIS DTMs display excellent agreement with nested Mars Reconnaissance Orbiter Context Camera (CTX), Mars Express’s High-Resolution Stereo Camera (HRSC), and Mars Orbiter Laser Altimeter (MOLA) DTMs at large-scale, and meanwhile, show fairly good correlation with the High-Resolution Imaging Science Experiment (HiRISE) DTMs for fine-scale details. In addition, we show how MADNet outperforms traditional photogrammetric methods, both on speed and quality, for other datasets like HRSC, CTX, and HiRISE, without any parameter tuning or re-training of the model. We demonstrate the results for Oxia Planum (the landing site of the European Space Agency’s Rosalind Franklin ExoMars rover 2023) and a couple of sites of high scientific interest.

Download Full-text

Modern Biodegradable Plastics—Processing and Properties Part II

Materials ◽

10.3390/ma14102523 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2523

Author(s):

Janusz W. Sikora ◽

Łukasz Majewski ◽

Andrzej Puszka

Keyword(s):

Water Vapor ◽

Rotational Speed ◽

Corn Starch ◽

Potato Starch ◽

Reference Sample ◽

Film Surface ◽

Barrier Properties ◽

Processing Parameters ◽

Biodegradable Plastics ◽

Film Blowing

Four different plastics were tested: potato starch based plastic (TPS-P)–BIOPLAST GF 106/02; corn starch based plastic (TPS-C)–BioComp BF 01HP; polylactic acid (polylactide) plastic (PLA)—BioComp BF 7210 and low density polyethylene, trade name Malen E FABS 23-D022; as a petrochemical reference sample. Using the blown film extrusion method and various screw rotational speeds, films were obtained and tested, as a result of which the following were determined: breaking stress, strain at break, static and dynamic friction coefficient of film in longitudinal and transverse direction, puncture resistance and strain at break, color, brightness and gloss of film, surface roughness, barrier properties and microstructure. The biodegradable plastics tested are characterized by comparable or even better mechanical strength than petrochemical polyethylene for the range of film blowing processing parameters used here. The effect of the screw rotational speed on the mechanical characteristics of the films obtained was also demonstrated. With the increase in the screw rotational speed, the decrease of barrier properties was also observed. No correlation between roughness and permeability of gases and water vapor was shown. It was indicated that biodegradable plastics might be competitive for conventional petrochemical materials used in film blowing niche applications where cost, recyclability, optical and water vapor barrier properties are not critical.

Download Full-text

Parallel Framework for Dimensionality Reduction of Large-Scale Datasets

Scientific Programming ◽

10.1155/2015/180214 ◽

2015 ◽

Vol 2015 ◽

pp. 1-12 ◽

Cited By ~ 3

Author(s):

Sai Kiranmayee Samudrala ◽

Jaroslaw Zola ◽

Srinivas Aluru ◽

Baskar Ganapathysubramanian

Keyword(s):

Dimensionality Reduction ◽

Organic Solar Cells ◽

Large Scale ◽

Parallel Implementation ◽

High Dimensional Data ◽

Real Life ◽

Processing Parameters ◽

High Dimensional ◽

Morphology Evolution ◽

Reduction Techniques

Dimensionality reduction refers to a set of mathematical techniques used to reduce complexity of the original high-dimensional data, while preserving its selected properties. Improvements in simulation strategies and experimental data collection methods are resulting in a deluge of heterogeneous and high-dimensional data, which often makes dimensionality reduction the only viable way to gain qualitative and quantitative understanding of the data. However, existing dimensionality reduction software often does not scale to datasets arising in real-life applications, which may consist of thousands of points with millions of dimensions. In this paper, we propose a parallel framework for dimensionality reduction of large-scale data. We identify key components underlying the spectral dimensionality reduction techniques, and propose their efficient parallel implementation. We show that the resulting framework can be used to process datasets consisting of millions of points when executed on a 16,000-core cluster, which is beyond the reach of currently available methods. To further demonstrate applicability of our framework we perform dimensionality reduction of 75,000 images representing morphology evolution during manufacturing of organic solar cells in order to identify how processing parameters affect morphology evolution.

Download Full-text

Polyamide 12/Multiwalled Carbon Nanotube and Carbon Black Nanocomposites Manufactured by 3D Printing Fused Filament Fabrication: A Comparison of the Electrical, Thermoelectric, and Mechanical Properties

C – Journal of Carbon Research ◽

10.3390/c7020038 ◽

2021 ◽

Vol 7 (2) ◽

pp. 38

Author(s):

Nectarios Vidakis ◽

Markos Petousis ◽

Lazaros Tzounis ◽

Emmanuel Velidakis ◽

Nikolaos Mountakis ◽

...

Keyword(s):

Mechanical Properties ◽

3D Printing ◽

Carbon Black ◽

Large Scale ◽

Fracture Mechanisms ◽

Fused Filament Fabrication ◽

Melt Mixing ◽

Multiwalled Carbon ◽

Electrically Conductive ◽

Polyamide 12

In this study, nanocomposites with polyamide 12 (PA12) as the polymer matrix and multiwalled carbon nanotubes (MWCNTs) and carbon black (CB) at different loadings (2.5, 5.0, and 10.0 wt.%) as fillers, were produced in 3D printing filament form by melt mixing extrusion process. The filament was then used to build specimens with the fused filament fabrication (FFF) three-dimensional (3D) printing process. The aim was to produce by FFF 3D printing, electrically conductive and thermoelectric functional specimens with enhanced mechanical properties. All nanocomposites’ samples were electrically conductive at filler loadings above the electrical percolation threshold. The highest thermoelectric performance was obtained for the PA12/CNT nanocomposite at 10.0 wt.%. The static tensile and flexural mechanical properties, as well as the Charpy’s impact and Vickers microhardness, were determined. The highest improvement in mechanical properties was observed for the PA12/CNT nanocomposites at 5.0 wt.% filler loading. The fracture mechanisms were identified by fractographic analyses of scanning electron microscopy (SEM) images acquired from fractured surfaces of tensile tested specimens. The nanocomposites produced could find a variety of applications such as; 3D-printed organic thermoelectric materials for plausible large-scale thermal energy harvesting applications, resistors for flexible circuitry, and piezoresistive sensors for strain sensing.

Download Full-text

Numerical investigation of localization and suppression of thermal decomposition of forest combustible materials using specialized water supply

MATEC Web of Conferences ◽

10.1051/matecconf/201819401033 ◽

2018 ◽

Vol 194 ◽

pp. 01033

Author(s):

Dmitrii Antonov ◽

Geniy Kuznetsov ◽

Alena Zhdanova

Keyword(s):

Thermal Decomposition ◽

Forest Fires ◽

Large Scale ◽

Water Film ◽

Decomposition Reaction ◽

Mutual Arrangement ◽

Near Surface ◽

The Times ◽

Forest Combustible ◽

Combustible Materials

The danger of forest fires and their large-scale consequences are becoming ever more complex problems for mankind every year. The results of numerical studies of heat transfer processes under suppressing the thermal decomposition reaction of forest combustible materials by films and groups of water droplets are presented. We used forest combustible materials, typical for the Siberian region. We have established the relationship between the dimensions of the heated near-surface layer of the material and the thickness of the film layer of the liquid that evaporated when the thermal decomposition reaction was suppressed in forest combustible materials. Typical times of suppression of the thermal decomposition reaction of typical forest combustible materials are given when the water film on the surface evaporates. The influence of the mutual arrangement of droplets on the surface of the forest combustible material and the temperature of the outer vapor-gas mixture on the times of suppression of its pyrolysis is revealed. The results can be used to develop technologies for extinguishing fires, containment of flame sources and combustion front.

Download Full-text

Effect of pulsed Nd:YAG laser processing parameters on surface properties of polyimide films

Surface and Coatings Technology ◽

10.1016/j.surfcoat.2019.01.025 ◽

2019 ◽

Vol 361 ◽

pp. 102-111 ◽

Cited By ~ 10

Author(s):

Huilong Liu ◽

Yong Tang ◽

Yingxi Xie ◽

Longsheng Lu ◽

Zhenping Wan ◽

...

Keyword(s):

Surface Properties ◽

Nd:Yag Laser ◽

Laser Processing ◽

Processing Parameters ◽

Polyimide Films ◽

Pulsed Nd:Yag Laser

Download Full-text

Application of variothermal heating concepts for the production of microstructured films using the extrusion embossing process

Journal of Polymer Engineering ◽

10.1515/polyeng-2012-0502 ◽

2012 ◽

Vol 32 (2) ◽

Cited By ~ 2

Author(s):

Walter Michaeli ◽

Stephan Eilbracht ◽

Micha Scharf ◽

Claudia Hartmann ◽

Kirsten Bobzin ◽

...

Keyword(s):

Temperature Profile ◽

Large Scale ◽

Cost Effective ◽

Processing Parameters ◽

Surface Structures ◽

Structured Surfaces ◽

Heating Systems ◽

External Heating

Abstract The application of the extrusion embossing process is a fast and cost-effective way to produce large-scale films with structured surfaces. In principle, microscopic and macroscopic surface structures can be manufactured this way. Particularly for the fabrication of microscopic structures, the reproduction accuracy can be remarkably improved by applying variothermal heating concepts for the embossing roll. In this article, two possible heating concepts are investigated: one laser-based and another using an inductor. The generated temperature profile along the circumference of the embossing roll is studied, taking the material of the embossing roll as well as different processing parameters into account. Both external heating systems (laser vs. inductor) are tested and compared. Furthermore, the improvement of the accuracy of the replicated microstructures is examined.

Download Full-text

Dispersion of Wood Microfibers in a Matrix of Thermoplastic Starch and Starch–Polylactic Acid Blend

Journal of Biobased Materials and Bioenergy ◽

10.1166/jbmb.2007.1980 ◽

2007 ◽

Vol 1 (1) ◽

pp. 71-77 ◽

Cited By ~ 12

Author(s):

Ayan Chakraborty ◽

Mohini Sain ◽

Mark Kortschot ◽

Sean Cutler

Keyword(s):

Polylactic Acid ◽

Polymer System ◽

Cellulose Fibers ◽

Thermoplastic Starch ◽

Processing Parameters ◽

Percentage Increase ◽

Melt Mixing ◽

Cellulose Microfibers ◽

Solution Cast ◽

Microscopy Images

The successful dispersion of cellulose fibers of submicrometer diameter in polymers has been restricted to solution-cast films so far. In this work, the dispersion of microfibers in biopolymers was investigated by melt-mixing using conventional processing equipment. Thermoplastic starch and a blend of starch and polylactic acid (PLA) were used as matrix materials. A suspension of cellulose microfibers less than 1 μm in diameter was prepared in water. This microfiber suspension was poured into molten thermoplastic starch to obtain fiber loadings up to 2%. The composites were compression molded into thin films roughly 0.25 mm thick. there was a 10% increase in tensile strength and a 50% increase in stiffness with each percentage increase in microfiber loading in the starch polymer. Similar improvement in tensile properties was also noted for a polymer system prepared by blending starch and PLA. Laser confocal microscopy images were analyzed to quantify microfiber dispersion at different composite processing parameters. This was the first work where successful dispersion of cellulose fibers of submicrometer was achieved in a composite prepared solely by the melt-mixing process.

Download Full-text

On the Progress of Combustion Synthesis of Si3N4 Ceramic: From Laboratory Research to Industrial Production

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.336-338.911 ◽

2007 ◽

Vol 336-338 ◽

pp. 911-915 ◽

Cited By ~ 3

Author(s):

Jiang Tao Li ◽

Yun Yang ◽

Hai Bo Jin

Keyword(s):

Mechanical Activation ◽

Combustion Synthesis ◽

Industrial Production ◽

Large Scale ◽

Processing Parameters ◽

Nitrogen Pressure ◽

Chemical Stimulation ◽

Ammonium Salts ◽

Laboratory Research ◽

The Past

The progress on the combustion synthesis of Si3N4 powders during the past decades was summarized with the emphasis on the recently developed mechano-chemically activated combustion synthesis (MACS) method. The effects of processing parameters such as the addition of diluent and ammonium salts into the green mixtures, the variation of nitrogen pressure as well as the mechanical activation treatment on the degree of Si to α-Si3N4 conversion was evaluated. The combination of mechanical activation and chemical stimulation was effective in enhancing the reactivity of Si powder reactants, which was responsible for the extension of the minimum nitrogen pressure normally required for the combustion synthesis of Si3N4. This breakthrough indicates that nitriding combustion of silicon in pressurized nitrogen could be promoted by activating the solid reactants instead of by increasing the pre-exerted nitrogen pressure. The MACS process was successfully applied to the industrial production of Si3N4 powders, the regularities for the large-scale synthesis were reported, and the as-synthesized Si3N4 powder products were systematically characterized.

Download Full-text