Thermal Decomposition Modeling and Thermophysical Property Measurement of a Highly Crosslinked Polymer Composite

2009 ◽  
Author(s):  
Aaron L. Brundage ◽  
Kenneth L. Erickson ◽  
Kevin J. Dowding
Keyword(s):  
Thermophysical Properties ◽  
Thermal Response ◽  
Laser Flash ◽  
Polymer Composition ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Inert Filler ◽  
Temperature Range ◽  
One Step ◽  
Practical Geometry

Thermophysical properties including density, specific heat, and thermal diffusivity of a poly (diallyl phthalate) inert filler composite material were characterized over a wide temperature range from room temperature to 800 °C. Over this temperature range, the material decomposition was approximated by a one-step process with first-order kinetics. Thermal kinetics data were obtained by thermal gravimetric analysis with Fourier transform infrared spectroscopy (TGA-FTIR) and thermophysical properties were obtained from differential scanning calorimetry (DSC) and laser flash diffusivity experiments. The response of the material to radiant heating was simulated with a computational heat transfer, multidimensional, finite element code. Additionally, the experimental uncertainty in the measurements was quantified to estimate the uncertainty in the reaction parameters due to heating rate and variability in inert filler-polymer composition in large sample sizes. Hence, the thermal response and the uncertainty were quantified for a complex decomposing material in a practical geometry for technologically important applications.

scholarly journals Wettability Control for Correct Thermophysical Properties Determination of Molten Salts and Their Nanofluids

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3765 ◽  
Author(s):  
Yaroslav Grosu ◽  
Luis González-Fernández ◽  
Udayashankar Nithiyanantham ◽  
Abdessamad Faik
Keyword(s):  
Thermophysical Properties ◽  
Molten Salts ◽  
Laser Flash ◽  
Concentrated Solar Power ◽  
Scanning Calorimetry ◽  
Sample Container ◽  
Low Surface Energy ◽  
Scale Roughness ◽  
Nanoscale Roughness

Proper recording of thermophysical properties for molten salts (MSs) and molten salts based nanofluids (MSBNs) is of paramount importance for the thermal energy storage (TES) technology at concentrated solar power (CSP) plants. However, it is recognized by scientific and industrial communities to be non-trivial, because of molten salts creeping (scaling) inside a measuring crucible or a sample container. Here two strategies are proposed to solve the creeping problem of MSs and MSBNs for the benefit of such techniques as differential scanning calorimetry (DSC) and laser flash apparatus (LFA). The first strategy is the use of crucibles with rough inner surface. It was found that only nanoscale roughness solves the creeping problem, while micron-scale roughness does not affect the wetting phenomena considerably. The second strategy is the use of crucible made of or coated with a low-surface energy material. Both strategies resulted in contact angle of molten salt higher than 90° and as a result, repeatable measurements in correspondence to the literature data. The proposed methods can be used for other characterization techniques where the creeping of molten salts brings the uncertainty or/and unrepeatability of the measurements.

scholarly journals Thermophysical properties of NP2 brand nickel

2021 ◽  
Vol 2119 (1) ◽  
pp. 012135
Author(s):  
D A Samoshkin ◽  
A Sh Agazhanov ◽  
S V Stankus
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermal Diffusivity ◽  
Thermophysical Properties ◽  
Magnetic Phase ◽  
Laser Flash ◽  
Scanning Calorimetry ◽  
Reference Table ◽  
Laser Flash Technique ◽  
Flash Technique

Abstract The heat capacity and the thermal diffusivity of NP2 brand nickel were investigated in the temperature interval 296–1000…1375 K of the solid-state, including the region of the magnetic phase transformation. Measurements were carried out on samples from one initial ingot by laser flash technique and method of differential scanning calorimetry using LFA-427 and DSC 404 F1 setups, respectively. The thermal conductivity was calculated based on the measured thermophysical properties. The estimated errors of the obtained results were 2–4%, 3–5%, and 2–3% for thermal diffusivity, thermal conductivity, and heat capacity, respectively. For investigated thermophysical properties the fitting equations and the reference table have been received.

scholarly journals Phase Polymorphism of [Mn(DMSO)6](BF4)2 Studied by Differential Scanning Calorimetry

2008 ◽  
Vol 63 (12) ◽  
pp. 808-812 ◽  
Author(s):  
Anna Migdał-Mikuli ◽  
Łukasz Skoczylas
Keyword(s):  
Differential Scanning Calorimetry ◽  
Phase Transitions ◽  
Dmso Molecule ◽  
Formula Unit ◽  
Scanning Calorimetry ◽  
First Order ◽  
Temperature Range ◽  
Phase Polymorphism ◽  
One Step ◽  
Solid Phases

The tetrafluoroborate of hexadimethylsulfoxidemanganese(II) was synthesized and studied by differential scanning calorimetry. Five solid phases of [Mn(DMSO)6](BF4)2 were revealed. Specifically, four phase transitions of the first order were detected between the following solid phases: stable KIb↔stable KIa at TC4 = 215 K; metastable KIII↔overcooled K0 at TC3 = 354 K; metastable KII↔overcooled K0 at TC2 =377 K; stable KIa→stable K0 at TC1 =385 K. [Mn(DMSO)6](BF4)2 starts to decompose at 400 K with a loss of one DMSO molecule per formula unit and forms [Mn(DMSO)5](BF4)2 which next decomposes in one step to MnF2 at the temperature range of 460 - 583 K. From the entropy changes it can be concluded that the phases K0 and metastable KII are orientationally dynamically disordered (ODDIC) crystals. The stable phases KIb and KIa are ordered solid phases.

scholarly journals Waste Electrical and Electronic Equipment Study regarding the plastic composition

2019 ◽  
Vol 56 (1) ◽  
pp. 77-81 ◽  
Author(s):  
Ramona Marina Grigorescu ◽  
Madalina Elena Grigore ◽  
Paul Ghioca ◽  
Lorena Iancu ◽  
Cristian-Andi Nicolae ◽  
...  
Keyword(s):  
Thermo Gravimetric Analysis ◽  
Polymeric Materials ◽  
Electronic Equipment ◽  
Polymer Composition ◽  
Gravimetric Analysis ◽  
Recycling Process ◽  
Scanning Calorimetry ◽  
Thermo Gravimetric ◽  
Important Concern ◽  
Complex Polymer

Waste electrical and electronic equipment (WEEE) generated in large amounts due to the development of IT and telecommunication industry is considered an important concern for environmental protection. The complex polymer composition of WEEE can be determined in order to consider a proper recycling process for polymeric materials. The aim of the study was to identify the constituent polymers by: density, burning test, solubility, Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), thermo-gravimetric analysis (ATG). The research led to a majority of polystyrenic polymers, together with polyesters, polycarbonates and polyamides.

scholarly journals Effect of Microstructure on Thermophysical Properties of Heat-Treated Duplex Steel

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6043
Author(s):  
Piotr Koniorczyk ◽  
Judyta Sienkiewicz ◽  
Janusz Zmywaczyk ◽  
Andrzej Dębski ◽  
Mateusz Zieliński ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Thermophysical Properties ◽  
Room Temperature ◽  
Laser Flash ◽  
Micro Hardness ◽  
Scanning Calorimetry ◽  
Air Atmosphere ◽  
Steel Bar ◽  
Heat Treated ◽  
Duplex Steel

The purpose of this study is to investigate the effect of heat treatments and resulting changes in microstructure on the thermophysical properties of commercial 1.4462 duplex stainless steel. Three types of heat treatment and a raw sample were used. In the first heat treatment, a duplex steel bar was annealed in an air atmosphere furnace for one hour at 1200 °C and then quickly cooled in water (1200 °C + water). The second heat treatment was the same as the first, but afterwards, the bar was annealed in an air atmosphere furnace for 4 h at 800 °C and then slowly cooled down in the furnace to room temperature (1200 °C + water + 800 °C). In the third heat treatment, the duplex steel bar was annealed in the furnace in an air atmosphere for one hour at 900 °C and then slowly cooled in the furnace to room temperature (900 °C). As a result, the weight percentages of ferrite and austenite in the samples achieved the following ratios: 75:25, 65:35 and 44:56. Light microscope examinations (LM), scanning electron microscopy (SEM), Vickers micro-hardness measurements and thermophysical studies using a laser flash apparatus (LFA), differential scanning calorimetry (DSC) and push-rod dilatometry (DIL) were performed to reveal the microstructure and changes in thermophysical properties including thermal diffusivity, thermal conductivity, thermal expansion and specific heat. Along with presenting these data, the paper, in brief, presents the applied investigation procedures.

scholarly journals Description of the concrete carbonation process with adjusted depth-resolved thermogravimetric analysis

2021 ◽  
Author(s):  
Nico Vogler ◽  
Philipp Drabetzki ◽  
Mathias Lindemann ◽  
Hans-Carsten Kühne
Keyword(s):  
Calcium Hydroxide ◽  
Bound Water ◽  
Reference Method ◽  
Microscopic Analysis ◽  
Limestone Powder ◽  
Gravimetric Analysis ◽  
Sample Material ◽  
Accelerated Carbonation ◽  
Temperature Range ◽  
Carbonation Process

AbstractThe thermal gravimetric analysis (TG) is a common method for the examination of the carbonation progress of cement-based materials. Unfortunately, the thermal properties of some components complicate the evaluation of TG results. Various hydrate phases, such as ettringite (AFt), C–S–H and AFm, decompose almost simultaneously in the temperature range up to 200 °C. Additionally, physically bound water is released in the same temperature range. In the temperature range between 450 °C and 600 °C, the decomposition of calcium hydroxide and amorphous or weakly bound carbonates takes place simultaneously. Carbonates, like calcite, from limestone powder or other additives may be already contained in the noncarbonated sample material. For this research, an attempt was made to minimise the influence of these effects. Therefore, differential curves from DTG results of noncarbonated areas and areas with various states of carbonation of the same sample material were calculated and evaluated. Concretes based on three different types of cement were produced and stored under accelerated carbonation conditions (1% CO2 in air). The required sample material was obtained by cutting slices from various depths of previously CO2-treated specimen and subsequent grinding. During the sample preparation, a special attention was paid that no additional carbonation processes took place. As reference method for the determination of the carbonation depth, the sprayed application of phenolphthalein solution was carried out. Microscopic analysis was examined to confirm the assumptions made previously. Furthermore, the observed effect of encapsulation of calcium hydroxide by carbonates caused by the accelerated carbonation conditions was examined more closely.

scholarly journals Utilization of Birch Bark as an Eco-Friendly Filler in Urea-Formaldehyde Adhesives for Plywood Manufacturing

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 511
Author(s):  
Roman Réh ◽  
Ľuboš Krišťák ◽  
Ján Sedliačik ◽  
Pavlo Bekhta ◽  
Monika Božiková ◽  
...  
Keyword(s):  
Bending Strength ◽  
Urea Formaldehyde ◽  
Formaldehyde Emission ◽  
Birch Bark ◽  
Gravimetric Analysis ◽  
European Standard ◽  
Scanning Calorimetry ◽  
Wood Processing ◽  
Fagus Sylvatica L ◽  
Positive Effect

The potential of using ground birch (Betula verrucosa Ehrh.) bark as an eco-friendly additive in urea-formaldehyde (UF) adhesives for plywood manufacturing was investigated in this work. Five-ply plywood panels were fabricated in the laboratory from beech (Fagus sylvatica L.) veneers bonded with UF adhesive formulations comprising three addition levels of birch bark (BB) as a filler (10%, 15%, and 20%). Two UF resin formulations filled with 10% and 20% wheat flour (WF) were used as reference samples. The mechanical properties (bending strength, modulus of elasticity and shear strength) of the laboratory-fabricated plywood panels, bonded with the addition of BB in the adhesive mixture, were evaluated and compared with the European standard requirements (EN 310 and EN 314-2). The mechanical strength of the plywood with the addition of BB in the adhesive mixture is acceptable and met the European standard requirements. Markedly, the positive effect of BB in the UF adhesive mixture on the reduction of formaldehyde emission from plywood panels was also confirmed. Initially, the most significant decrease in formaldehyde release (up to 14%) was measured for the plywood sample, produced with 15% BB. After four weeks, the decrease in formaldehyde was estimated up to 51% for the sample manufactured with 20% BB. The performed differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and derivative thermogravimetry (DTG), also confirmed the findings of the study. As this research demonstrated, BB as a waste or by-product of wood processing industry, can be efficiently utilized as an environmentally friendly, inexpensive alternative to WF as a filler in UF adhesive formulations for plywood manufacturing.

The effect of cooling rate on crystallization behavior and tensile properties of CF/PEEK composites

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Guangming Dai ◽  
Lihua Zhan ◽  
Chenglong Guan ◽  
Minghui Huang
Keyword(s):  
Cooling Rate ◽  
Crystallization Temperature ◽  
Crystallization Behavior ◽  
Crystalline Polymer ◽  
Scanning Calorimetry ◽  
Nonisothermal Crystallization ◽  
Cooling Rates ◽  
Control Range ◽  
Temperature Range ◽  
Transverse Tensile

Abstract In this study, the differential scanning calorimetry (DSC) tests were performed to measure the nonisothermal crystallization behavior of carbon fiber reinforced polyether ether ketone (CF/PEEK) composites under different cooling rates. The characteristic parameters of crystallization were obtained, and the nonisothermal crystallization model was established. The crystallization temperature range of the material at different cooling rates was predicted by the model. The unidirectional laminates were fabricated at different cooling rates in the crystallization temperature range. The results showed that the crystallization temperature range shifted to a lower temperature with the increase of cooling rate, the established nonisothermal crystallization model was consistent with the DSC test results. It is feasible to shorten the cooling control range from the whole process to the crystallization range. The crystallinity and transverse tensile strength declined significantly with the increase of the cooling rate in the crystallization temperature range. The research results provided theoretical support for the selection of cooling conditions and temperature control range, which could be applied to the thermoforming process of semi-crystalline polymer matrixed composites to improve the manufacturing efficiency.

scholarly journals Enhancement of Antioxidant and Hydrophobic Properties of Alginate via Aromatic Derivatization: Preparation, Characterization, and Evaluation

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2575
Author(s):  
Smaher M. Elbayomi ◽  
Haili Wang ◽  
Tamer M. Tamer ◽  
Yezi You
Keyword(s):  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Benzoyl Group ◽  
Antioxidant Evaluation ◽  
Thermo Stability

The preparation of bioactive polymeric molecules requires the attention of scientists as it has a potential function in biomedical applications. In the current study, functional substitution of alginate with a benzoyl group was prepared via coupling its hydroxyl group with benzoyl chloride. Fourier transform infrared spectroscopy indicated the characteristic peaks of aromatic C=C in alginate derivative at 1431 cm−1. HNMR analysis demonstrated the aromatic protons at 7.5 ppm assigned to benzoyl groups attached to alginate hydroxyl groups. Wetting analysis showed a decrease in hydrophilicity in the new alginate derivative. Differential scanning calorimetry and thermal gravimetric analysis showed that the designed aromatic alginate derivative demonstrated higher thermo-stability than alginates. The aromatic alginate derivative displayed high anti-inflammatory properties compared to alginate. Finally, the in vitro antioxidant evaluation of the aromatic alginate derivative showed a significant increase in free radical scavenging activity compared to neat alginate against DPPH (2,2-diphenyll-picrylhydrazyl) and ABTS free radicals. The obtained results proposed that the new alginate derivative could be employed for gene and drug delivery applications.

scholarly journals Biocomposites of Bio-Polyethylene Reinforced with a Hydrothermal-Alkaline Sugarcane Bagasse Pulp and Coupled with a Bio-Based Compatibilizer

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2158
Author(s):  
Nanci Vanesa Ehman ◽  
Diana Ita-Nagy ◽  
Fernando Esteban Felissia ◽  
María Evangelina Vallejos ◽  
Isabel Quispe ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Water Absorption ◽  
Sugarcane Bagasse ◽  
Thermo Gravimetric Analysis ◽  
Decomposition Temperature ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Cradle To Gate ◽  
Bagasse Pulp

Bio-polyethylene (BioPE, derived from sugarcane), sugarcane bagasse pulp, and two compatibilizers (fossil and bio-based), were used to manufacture biocomposite filaments for 3D printing. Biocomposite filaments were manufactured and characterized in detail, including measurement of water absorption, mechanical properties, thermal stability and decomposition temperature (thermo-gravimetric analysis (TGA)). Differential scanning calorimetry (DSC) was performed to measure the glass transition temperature (Tg). Scanning electron microscopy (SEM) was applied to assess the fracture area of the filaments after mechanical testing. Increases of up to 10% in water absorption were measured for the samples with 40 wt% fibers and the fossil compatibilizer. The mechanical properties were improved by increasing the fraction of bagasse fibers from 0% to 20% and 40%. The suitability of the biocomposite filaments was tested for 3D printing, and some shapes were printed as demonstrators. Importantly, in a cradle-to-gate life cycle analysis of the biocomposites, we demonstrated that replacing fossil compatibilizer with a bio-based compatibilizer contributes to a reduction in CO2-eq emissions, and an increase in CO2 capture, achieving a CO2-eq storage of 2.12 kg CO2 eq/kg for the biocomposite containing 40% bagasse fibers and 6% bio-based compatibilizer.

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