scholarly journals Fabrication and Characterization of Multiscale PLA Structures Using Integrated Rapid Prototyping and Gas Foaming Technologies

Nanomaterials ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 575 ◽  
Author(s):  
Byung Park ◽  
David Hwang ◽  
Dong Kwon ◽  
Tae Yoon ◽  
Youn-Woo Lee
Keyword(s):  
Rapid Prototyping ◽  
Mechanical Strength ◽  
Thermal Insulation ◽  
Functional Materials ◽  
Morphological Characterization ◽  
Scanning Calorimetry ◽  
3D Printed ◽  
Foaming Temperature ◽  
Gas Foaming

Multiscale structured polymers have been considered as a promising category of functional materials with unique properties. We combined rapid prototyping and gas foaming technologies to fabricate multiscale functional materials of superior mechanical and thermal insulation properties. Through scanning electron microscope based morphological characterization, formation of multiscale porous structure with nanoscale cellular pores was confirmed. Improvement in mechanical strength is attributed to rearrangement of crystals within CO2 saturated grid sample. It is also shown that a post-foaming temperature higher than the glass transition temperature deteriorates mechanical strength, providing process guidelines. Thermal decomposition of filament material sets the upper limit of temperature for 3D printed features, characterized by simultaneous differential scanning calorimetry and thermogravimetric analysis. Porosity of the fabricated 3D structured polylactic acid (PLA) foam is controllable by suitable tuning of foaming conditions. The fabricated multiscale 3D structures have potential for thermal insulation applications with lightweight and reasonable mechanical strength.

scholarly journals Thermal and Mechanical Characterization of Copolymer Structure with Gradient Foam Using Additive Manufacturing and CO2 Foaming

2019 ◽  
Author(s):  
Byung Kyu Park ◽  
Charn-Jung Kim ◽  
Dong Eui Kwon ◽  
Youn-Woo Lee
Keyword(s):  
Mechanical Strength ◽  
Thermal Insulation ◽  
Thermo Gravimetric Analysis ◽  
Measurement Data ◽  
Functional Materials ◽  
Functionally Graded ◽  
Gravimetric Analysis ◽  
Polyethylene Naphthalate ◽  
Data Set ◽  
Foaming Temperature

Synthetic polymer-based gradient foams have considered as promising category of functionally graded materials with unique properties. In this study, the carbon dioxide (CO2) foaming technology has used for PET-PEN (Polyethylene Terephthalate - Polyethylene Naphthalate) copolymer towards porous functional materials with thermal insulation with reasonable mechanical strength. Through scanning electron microscope based morphological characterization, a potential to fabricate gradient foam structures with micro-pores has identified. It has shown that variation of post-foaming temperature can tune the pore size distribution although the very high post-foaming temperature tends to cause structural instability. Thermal measurement data set the limits of operation, confirmed by simultaneous differential scanning calorimeter and thermo-gravimetric analysis. Mechanical stress and thermal conductivity also has measured to find rationale of thermal insulation with reasonable mechanical strength and to elucidate the actual 3D grid foam of copolymer.

scholarly journals Design and Fabrication of Partially Foamed Grid Structure Using Additive Manufacturing and Solid State Foaming

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1594
Author(s):  
Byung Kyu Park ◽  
Charn-Jung Kim ◽  
Dong Eui Kwon ◽  
Youn-Woo Lee
Keyword(s):  
Mechanical Strength ◽  
Lattice Structure ◽  
Functional Materials ◽  
Morphological Characterization ◽  
Functionally Graded ◽  
Melting Points ◽  
Graded Materials ◽  
Thermal Data ◽  
Foaming Temperature ◽  
Foaming Technology

A partially foamed lattice structure based on synthetic polymers was considered as a functionally graded materials due to their unique properties. In this study, a copolymer is manufactured to be porous functional materials by physical foaming technology, using carbon dioxide. Through morphological characterization, using scanning electron microscope, we identified a potential to fabricate partially foamed structures with micropores. We showed that variation of post-foaming temperature can tune the pore size distribution in the range of 0.9 to 30 μm. Thermal data of the foam grid from differential scanning calorimeter showed some shifts in glass transition, cold crystallization, and melting points. Mechanical strength and thermal conductivity were also measured to find rationale of thermal insulation with tunable mechanical strength and to elucidate the actual 3D lattice foam of a copolymer.

Mechanical and morphological characterization of 3D-printed carbonPEEK composite for avionic shimming

2021 ◽  
Author(s):  
Pietro Russo ◽  
Antonio Langella ◽  
Giulia Leone ◽  
Gennaro D'Angelo ◽  
Pietro Ferraro ◽  
...  
Keyword(s):  
Morphological Characterization ◽  
3D Printed

scholarly journals Thermal characterization of fibrous aerogel blanket

2019 ◽  
Vol 282 ◽  
pp. 01001 ◽  
Author(s):  
Ákos Lakatos ◽  
Anton Trnik
Keyword(s):  
Thermal Annealing ◽  
Thermal Insulation ◽  
Thermal Characterization ◽  
Insulation Material ◽  
Scanning Calorimetry ◽  
Solid Materials ◽  
Plastic Foams ◽  
Isothermal Heat Treatments ◽  
New Buildings

Nowadays, the application of thermal insulation materials both by the existing and by new buildings is one of the most important actions in order to reduce the energy loss of buildings. Besides the use of the conventional insulations (plastic foams and wool materials) aerogel is one of the most promising thermal insulation material. Aerogels, one of the lightest solid materials available today, are manufactured through the combination of a polymer with a solvent forming a gel. For buildings the fibre reinforced ones are the mainly used types. It is produced by adding the liquid-solid solution to the fibrous batting. In this paper changes in the thermal performance of the aerogel blanket will be followed after thermal annealing. The samples will be put under isothermal heat treatments at 70 °C for 6 weeks, as well as they will be put under thermal treatment at higher temperatures (from 70 °C till 210 °C) for 1 day. The changes in the thermal conductivity will be followed by Holometrix Lambda heat flow meter, as well as, Differential Scanning Calorimetry results will be presented. From the measured values, thermal properties will be calculated. In this paper we will try to clarify the role played by thermal annealing in thermal diffusivity.

scholarly journals Faithful Scanning Electron Microscopic (SEM) visualization of 3D printed alginate-based scaffolds

2020 ◽  
Author(s):  
Marcus Koch ◽  
Małgorzata K. Włodarczyk-Biegun
Keyword(s):  
High Water ◽  
Morphological Characterization ◽  
High Water Content ◽  
Electron Microscopic ◽  
Cross Sectional ◽  
3D Architecture ◽  
3D Printed ◽  
Preparation Techniques ◽  
Scanning Electron

AbstractThe morphological characterization of 3D printed hydrogel-based scaffolds is essential for monitoring their size, shape, surface texture and internal structure. Among other microscopic techniques, Scanning Electron Microscopy (SEM) is capable of visualizing nearly all kinds of materials at different length scales, with exceptional precision, if investigation under vacuum is possible. However, due to the high water content of hydrogel-based scaffolds and the connected volume change after drying, special preparation techniques are necessary to stabilize the 3D architecture when imaged by SEM. Here we present a straightforward cryo-SEM technique to visualize 3D printed hydrogel-based alginate scaffolds. By use of a homemade cryo-SEM holder and plunge-freezing in liquid ethane, scaffolds are visualized from the top and cross-sectional view at different magnifications. The proposed method is compared with SEM imaging in different modes (cyro-SEM, conventional SEM, ESEM) following other commonly used sample preparation techniques, such as plunging in liquid nitrogen, air-drying, freeze-drying and plunging in liquid ethane after graded dehydration. These approaches, except ESEM, lead to shrinkage, deformation, distortion or disintegration of the scaffolds and consequently give rise to artifacts in imaging. The presented results indicate that cryo-SEM after plunging in liquid ethane allows for the most faithful and time-efficient visualization of 3D printed alginate scaffolds.

scholarly journals METHODOLOGIES FOR THE STUDY OF MORPHOLOGICAL AND THERMAL PROPERTIES OF STARCH

2018 ◽  
Vol 5 (3) ◽  
pp. 187-195
Author(s):  
Juliana Aparecida Correia Bento ◽  
Karen Carvalho Ferreira ◽  
Priscila ZaczuK Bassinello ◽  
Menandes Alves De Souza Neto
Keyword(s):  
Electron Microscopy ◽  
Thermal Properties ◽  
Food Industry ◽  
Starch Granule ◽  
Morphological Characterization ◽  
Technological Properties ◽  
Scanning Calorimetry ◽  
Main Component ◽  
Scanning Electron

Starch, a carbohydrate used as a reserve of energy in most plants, is widely used in the food industry, either as a main component or as a thickener. Considering the application of this as an ingredient in the food industry, the study of the morphological and thermal properties of this food is of great importance because it can predict its behavior during and after the processing of this. Methodologies such as scanning electron microscopy, light scattering and optical microscopy are the most used tools in the morphological characterization of the starch granule generating accurate results and good quality. Regarding the methodologies for the study of thermal properties, the rapid amylographic analyzer and the differential scanning calorimetry are the most used. The set of results obtained with these methodologies, allows to know the technological properties of the starch, characterizing them, and even to identify the origin of this one.

The effect of alkaline–silane treatment of rubberwood flour for water absorption and mechanical properties of plastic composites

2018 ◽  
Vol 33 (5) ◽  
pp. 599-613 ◽  
Author(s):  
Sriwan Khamtree ◽  
Thanate Ratanawilai ◽  
Sukritthira Ratanawilai
Keyword(s):  
Mechanical Properties ◽  
Mechanical Strength ◽  
Water Absorption ◽  
Morphological Characterization ◽  
Silane Treatment ◽  
Plastic Composites ◽  
Treatment Conditions ◽  
Twin Screw ◽  
Effect Of Treatment

Rubberwood flour (RWF) was treated by alkaline, silane, and alkaline–silane, and consequently, reinforced recycled polypropylene (rPP) composites. The wood–plastic composites (WPCs) were prepared with 40 wt% RWF content using a twin-screw extruder, followed by compression molding. Silane treatment was applied at various concentrations and treatment times to evaluate the effect of treatment conditions on water absorption, mechanical properties, thermal properties, and morphological characterization of WPCs. The results indicated that alkaline–silane treatment of RWF exhibits higher properties in comparison to silane or alkaline only. In addition, silane concentrations significantly affected water absorption, mechanical strength, and hardness, while treatment times remained relatively unaffected by these properties. The best water resistance, mechanical strength, and hardness of WPCs were achieved by alkaline–silane treatment with 5% silane concentration for 2 h, which improved the interfacial adhesion of RWF and rPP as well as increased the crystallinity in the WPCs.

scholarly journals Alternating Gyroid Network Structure in an ABC Miktoarm Terpolymer Comprised of Polystyrene and Two Polydienes

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1497 ◽  
Author(s):  
Dimitrios Moschovas ◽  
Gkreti-Maria Manesi ◽  
Andreas Karydis-Messinis ◽  
George Zapsas ◽  
Konstantinos Ntetsikas ◽  
...  
Keyword(s):  
Network Structure ◽  
Morphological Characterization ◽  
Degree Of Polymerization ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Three Phase ◽  
Microdomain Structure

The synthesis, molecular and morphological characterization of a 3-miktoarm star terpolymer of polystyrene (PS, M¯n = 61.0 kg/mol), polybutadiene (PB, M¯n = 38.2 kg/mol) and polyisoprene (PI, M¯n = 29.2 kg/mol), corresponding to volume fractions (φ) of 0.46, 0.31 and 0.23 respectively, was studied. The major difference of the present material from previous ABC miktoarm stars (which is a star architecture bearing three different segments, all connected to a single junction point) with the same block components is the high 3,4-microstructure (55%) of the PI chains. The interaction parameter and the degree of polymerization of the two polydienes is sufficiently positive to create a three-phase microdomain structure as evidenced by differential scanning calorimetry and transmission electron microscopy (TEM). These results in combination with small-angle X-ray scattering (SAXS) and birefringence experiments suggest a cubic tricontinuous network structure, based on the I4132 space group never reported previously for such an architecture.

Optical and morphological characterization of a 3D printed intraocular lens

2014 ◽  
Vol 92 ◽  
pp. 0-0
Author(s):  
G DEBELLEMANIERE ◽  
M FLORES ◽  
M MONTARD ◽  
B DELBOSC ◽  
M SALEH
Keyword(s):  
Intraocular Lens ◽  
Morphological Characterization ◽  
3D Printed

Morphological Characterization of Mycobacteriophage R1

1974 ◽  
Vol 32 ◽  
pp. 254-255
Author(s):  
B. L. Soloff ◽  
T. A. Rado
Keyword(s):  
Carbon Source ◽  
Stationary Phase ◽  
Growth Phase ◽  
Minimal Medium ◽  
Morphological Characterization ◽  
Logarithmic Growth Phase ◽  
Complete Lysis ◽  
Lysogenic Culture ◽  
Logarithmic Growth

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.

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