scholarly journals Effect of Morphological Changes due to Increasing Carbon Nanoparticles Content on the Quasi-Static Mechanical Response of Epoxy Resin

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1106 ◽  
Author(s):  
Hamed Yazdani Nezhad ◽  
Vijay Kumar Thakur
Keyword(s):  
Epoxy Resin ◽  
Carbon Nanoparticles ◽  
High Performance ◽  
Mechanical Response ◽  
Epoxy Polymer ◽  
Mechanical Performance ◽  
Morphological Changes ◽  
Industrial Process ◽  
Weight Percentage ◽  
Low Viscosity

Mechanical failure in epoxy polymer and composites leads them to commonly be referred to as inherently brittle due to the presence of polymerization-induced microcrack and microvoids, which are barriers to high-performance applications, e.g., in aerospace structures. Numerous studies have been carried out on epoxy’s strengthening and toughening via nanomaterial reinforcement, e.g., using rubber nanoparticles in the epoxy matrix of new composite aircraft. However, extremely cautious process and functionalization steps must be taken in order to achieve high-quality dispersion and bonding, the development of which is not keeping pace with large structures applications. In this article, we report our studies on the mechanical performance of an epoxy polymer reinforced with graphite carbon nanoparticles (CNPs), and the possible effects arising from a straightforward, rapid stir-mixing technique. The CNPs were embedded in a low viscosity epoxy resin, with the CNP weight percentage (wt %) being varied between 1% and 5%. Simplified stirring embedment was selected in the interests of industrial process facilitation, and functionalization was avoided to reduce the number of parameters involved in the study. Embedment conditions and timing were held constant for all wt %. The CNP filled epoxy resin was then injected into an aluminum mold and cured under vacuum conditions at 80 °C for 12 h. A series of test specimens were then extracted from the mold, and tested under uniaxial quasi-static tension, compression, and nanoindentation. Elementary mechanical properties including failure strain, hardness, strength, and modulus were measured. The mechanical performance was improved by the incorporation of 1 and 2 wt % of CNP but was degraded by 5 wt % CNP, mainly attributed to the morphological change, including re-agglomeration, with the increasing CNP wt %. This change strongly correlated with the mechanical response in the presence of CNP, and was the major governing mechanism leading to both mechanical improvement and degradation.

A CASE STUDY OF BIOCOMPOSITE MATERIAL USE IN AUTOMOTIVE APPLICATIONS

2021 ◽  
Author(s):  
DANIEL WALCZYK ◽  
RONALD BUCINELL ◽  
STEVEN FLEISHMAN ◽  
SHARMAD JOSHI
Keyword(s):  
High Performance ◽  
Mechanical Performance ◽  
Flexural Modulus ◽  
Tensile Modulus ◽  
Maximum Tensile Stress ◽  
High Viscosity ◽  
Flexural Stress ◽  
Fiber Volume ◽  
Low Viscosity ◽  
Biocomposite Material

Interest in biocomposites is growing worldwide as companies that manufacture high-performance products seek out more sustainable material options. Although there is significant research on biocomposite material options and processing found in the literature from at least the last two decades, there are few experimentally based case studies published to help guide product designers and engineers when considering these materials. This paper discusses the use of biocomposites in the seat of an electric bus. Although it is clear that biocomposite material options are quite limited, the authors eventually settled on three natural reinforcements (cellulose, hemp, flax), two epoxies (one low and the other high viscosity) with high biobased carbon content, and one flax precoated with bioepoxy for consideration. Laminate plates with a 4mm nominal thickness are manufactured using VARTM (low viscosity epoxy only), hand layup as a surrogate for prepregging (high viscosity epoxy only), compression molding, and an out-of-autoclave process called the Pressure Focusing Layer (PFL) method. Permeability of the three reinforcements infused with the high viscosity epoxy and fiber volume fractions are determined experimentally to provide insight into VARTM processing and mechanical performance. The tensile modulus, maximum tensile stress, flexural modulus, and maximum flexural stress are measured for all combinations of reinforcement, resin, and processing using tension testing and three-point bending based on ASTM standards. Basic conclusions are drawn about the specific application and more generally about the process of using biocomposites in commercial products.

scholarly journals Thermal and Reliability Characterization of an Epoxy Resin-Based Double-Side Cooled Power Module

2021 ◽  
Vol 18 (3) ◽  
pp. 123-136
Author(s):  
Tzu-Hsuan Cheng ◽  
Kenji Nishiguchi ◽  
Yoshi Fukawa ◽  
B. Jayant Baliga ◽  
Subhashish Bhattacharya ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
High Power ◽  
High Performance ◽  
Mechanical Performance ◽  
Resin Composite ◽  
Wide Band ◽  
Cost Effective ◽  
Power Module ◽  
Wide Band Gap ◽  
Epoxy Resin Composite

Abstract Wide-Band Gap (WBG) power devices have become a promising option for high-power applications due to the superior material properties over traditional Silicon. To not limit WBG devices’ mother nature, a rugged and high-performance power device packaging solution is necessary. This study proposes a Double-Side Cooled (DSC) 1.2 kV half-bridge power module having dual epoxy resin insulated metal substrate (eIMS) for solving convectional power module challenges and providing a cost-effective solution. The thermal performance outperforms traditional Alumina (Al2O3) Direct Bonded Copper (DBC) DSC power module due to moderate thermal conductivity (10 W/mK) and thin (120 mm) epoxy resin composite dielectric working as the IMS insulation layer. This novel organic dielectric can withstand high voltage (5 kVAC @ 120 μm) and has a Glass Transition Temperature (Tg) of 300°C, which is suitable for high-power applications. In the thermal-mechanical modeling, the organic DSC power module can pass the thermal cycling test over 1,000 cycles by optimizing the mechanical properties of the encapsulant material. In conclusion, this article not only proposes a competitive organic-based power module but also a methodology of evaluation for thermal and mechanical performance.

scholarly journals Manufacture of Hybrid Natural/Synthetic Fiber Woven Textiles for Use in Technical Biocomposites with Maximum Biobased Content

2019 ◽  
Vol 3 (2) ◽  
pp. 43 ◽  
Author(s):  
Madina Shamsuyeva ◽  
Jana Winkelmann ◽  
Hans-Josef Endres
Keyword(s):  
Epoxy Resin ◽  
Feasibility Study ◽  
High Performance ◽  
Mechanical Performance ◽  
Synthetic Fiber ◽  
Flexural Properties ◽  
Synthetic Fibers ◽  
Flax Fibers ◽  
Promising Solution ◽  
Biobased Content

This feasibility study investigates the flexural properties of biocomposites containing woven flax textiles (plain, twill, satin) and woven twill patterned hybrid textiles containing flax-/glass or flax-/carbon mixture for lightweight applications. Synthetic fibers are integrated as weft and flax fibers are integrated as warp yarns using a double-rapier weaving machine with a Jacquard attachment. The corresponding biocomposites are manufactured via vacuum infusion process using a biobased epoxy resin as a matrix. The manufactured biocomposites are analyzed with regard to their density and flexural properties. The results show that the use of hybrid textiles offers a promising solution for the manufacture of biocomposites with a higher biobased content and significantly improved flexural properties. Furthermore, the introduction of high-performance synthetic fibers in textiles enables the manufacture of biocomposites with an isotropic mechanical performance.

Studies of the Physical Properties of Cycloaliphatic Epoxy Resin Reacted with Anhydride Curing Agents

2017 ◽  
Vol 737 ◽  
pp. 248-255 ◽  
Author(s):  
Tae Hee Kim ◽  
Dae Yeon Kim ◽  
Choong Sun Lim ◽  
Bong Kuk Seo
Keyword(s):  
Physical Properties ◽  
Reaction Kinetics ◽  
Epoxy Resin ◽  
High Performance ◽  
Industrial Applications ◽  
Scanning Calorimetry ◽  
Low Viscosity ◽  
High Performance Polymer ◽  
Curing Agents ◽  
The Impact

The preparation of high performance epoxy composites for industrial applications has been extensively researched. In this report, we study the change in physical properties and reaction kinetics between epoxy resin and curing agents of similar geometry. For the experiments, celloxide 2021P, an epoxy resin having low viscosity, was blended with three different curing agents: methylhexahydropthalic acid, methyltetrahydropthalic acid, and 5-norbornene-2, 3-dicarboxylic anhydride. The amount of 1, 2-dimethylimidazole catalyst was controlled, and the highest heat flow temperature (Tpeak) was observed at around 145 °C. The impact on reaction kinetics relative to the change in heating rate was studied with differential scanning calorimetry (DSC) for each of the curing agents. The glass transition temperature (Tg) of each composition was measured with a second DSC cycle. The prepared epoxy compositions were thermally cured in a metallic mold to provide pure epoxy resins without fillers. Finally, the flexural strengths of these resins were compared to each other. The authors believe that insights into choosing an appropriate epoxy binder are useful when it comes to the overall preparation of high performance polymer composites.

High-Performance Silica/Epoxy Resin Hybrid Materials Prepared by In Situ Sol-Gel Process

2011 ◽  
Vol 308-310 ◽  
pp. 804-807
Author(s):  
Jian Jiao ◽  
Liang Zou ◽  
Pan Bo Liu ◽  
Guang Li Wu
Keyword(s):  
Electron Microscopy ◽  
Heat Resistance ◽  
Epoxy Resin ◽  
Hybrid Materials ◽  
High Performance ◽  
Mechanical Performance ◽  
Sol Gel ◽  
Mechanical And Thermal Properties ◽  
In Suit ◽  
Gel Temperature

Silica/epoxy resin hybrid materials are prepared with tetraethylorthosilicate (Si(OC2H5)4, TEOS) and γ-aminoproplytriethyoxysiliane (H2N(CH2)3Si(OC2H5)3, APTES) as the silica sources, epoxy resin as the polymer matrix, by the means of in-suit sol-gel method. The dosages of TEOS and APTES in preparation of hybrid materials, and the sol-gel temperature for silica resources are discussed to make sure of the influence of the structure and properties on hybrid materials. The dispersion of Silica in the epoxy resin are examined by transmission electron microscopy (TEM).The image of fracture surfaces of hybrid materials are examined by scanning electron microscopy (SEM). The glass transmission temperatures (Tg) are tested by differential scanning calorimeter (DSC) to characterize the heat resistance of hybrid materials. The optimum mechanical performance and heat resistance for silica/epoxy resin hybrid materials are achieved with 3wt% TEOS and APTES 2wt% employed in this materials when sol-gel temperature is 60°C. In general, the mechanical and thermal properties of the hybrid materials were improved greatly as compared with the pure epoxy resin.

scholarly journals Size Effects on Thermo-Mechanical Performance of U-10Mo Monolithic Fuel Plates

2019 ◽  
Author(s):  
Hakan Ozaltun ◽  
Hee Seok Roh ◽  
Walid Mohamed
Keyword(s):  
High Performance ◽  
Mechanical Response ◽  
Mechanical Performance ◽  
Operating Conditions ◽  
Temperature Deformation ◽  
Safety Standards ◽  
Plate Size ◽  
Successful Testing ◽  
Deformation Stress ◽  
Irradiation Performance

Abstract Monolithic fuel is a fuel form that is considered for the conversion of high performance research reactors. This plate-type fuel consists of a high density U-Mo fuel in monolithic form that is sandwiched between zirconium diffusion barriers, and encapsulated in an aluminum cladding. To date, large number of plates have been irradiated with satisfactory perforamce. The program is now moving into the qualification phase, a predecessor to the timely conversion of the target reactors. It must be shown that the fuel system meets the safety standards and performs well in reactor. The requirement to satisfactory irradiation performance under normal operating conditions is primarily demonstrated by a successful testing. Since each reactor employs distinct fuel plate geometries for various consideration with unique plate design features and attributes, a single “generic” plate geometry capturing all of the extremities is not achievable. Furthermore, testing all these geometric and irradiation parameters on a large size plate is not practical. Therefore, a smaller, “down-scaled” versions of fuel plates, are often employed for experimental purposes. This limitation consequently requires much more cautious performance evaluations, as thermal and mechanical response of a plate with certain geometry may not be representative for a plate with a different geometry. To investigate if plate size has any effects on irradiation performance, the plates with various geometric dimensions were parametrically evaluated. In particular, length and width of the plates were varied between the bounding values. Temperature, deformation, stress values were comparatively evaluated. The results have indicated that effects of geometric ratios and plate size variations in length and width directions are insignificant. However, wider plates could become more prone to a warping-type deformation, if there are nonlinearities.

scholarly journals Effects of Plate Curvature on Thermo-Mechanical Performance of U-10Mo Monolithic Fuel Plates

2019 ◽  
Author(s):  
Hakan Ozaltun ◽  
Hee Seok Roh ◽  
Walid Mohamed
Keyword(s):  
High Performance ◽  
Mechanical Response ◽  
Mechanical Performance ◽  
Geometric Parameters ◽  
Temperature Deformation ◽  
Plate Design ◽  
Plate Curvature ◽  
Deformation Stress ◽  
Performance Research ◽  
Plate Geometry

Abstract Monolithic fuel is a candidate fuel form being considered for the conversion of high-performance research reactors. This plate-type fuel consists of a high-density, U-Mo fuel in a monolithic form that is sandwiched between zirconium diffusion barriers, and encapsulated in an aluminum cladding. To date, large number of plates have been irradiated with satisfactory performance. The program is now moving into the qualification phase, a predecessor to the timely conversion of the target reactors. Since each reactor employs distinct fuel plate geometries for various consideration, resulting nearly 50 distinct plate geometries with unique plate design features, a single “generic” plate geometry capturing all of the extremities is not achievable. This limitation consequently requires much more cautious performance evaluations, as thermal and mechanical response of a plate with certain geometry may not be representative for a plate with a different geometry. To evaluate the performance of the plates for various geometric parameters, parametric sensitives studies have been employed. One of the important geometric parameters may have potential effects on the performance is the plate curvature. In this study, curved-plates were parametrically simulated to investigate if this geometric parameter has any effects on overall performance, In particular, radius of curvatures of the plates were varied between the bounding values, and the plates were simulated for comparable irradiation histories. The resulted temperature, deformation, stress-strain results were comparatively evaluated. The results have indicated that preferential deformations occur. This consequently caused shifting of plate centerline on curved plates. The magnitude of centerline shifts increased with increasing plate curvatures.

scholarly journals Parametric Study of Strain Rate Effects on Nanoparticle-Reinforced Polymer Composites

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
B. Soltannia ◽  
I. Haji Gholami ◽  
S. Masajedian ◽  
P. Mertiny ◽  
D. Sameoto ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Epoxy Resin ◽  
Polymer Composites ◽  
Parametric Study ◽  
Mechanical Response ◽  
Absorption Capacity ◽  
Weight Percentage ◽  
Reinforced Polymer ◽  
Recent Emergence

Crashworthiness, energy absorption capacity, and safety are important factors in the design of lightweight vehicles made of fiber-reinforced polymer composite (FRP) components. The relatively recent emergence of the nanotechnology industry has presented a novel means to augment the mechanical properties of various materials. As a result, recent attempts have contemplated the use of nanoparticles to further improve the resiliency of resins, especially when resins are used for mating FRP components. Therefore, a comprehensive understanding of the response of nanoreinforced polymer composites, subjected to various rates of loading, is of paramount importance for developing reliable structures. In this paper, the effects of nanoreinforcement on the mechanical response of a commonly used epoxy resin subjected to four different strain rates, are systematically investigated. The results are then compared to those of the neat resin. To characterize the mechanical properties of the nanocomposite, a combination of the strain rate-dependent mechanical (SRDM) model of Goldberg and his coworkers and Halpin-Tsai’s micromechanical approach is employed. Subsequently, a parametric study is conducted to ascertain the influences of particle type and their weight percentage. Finally, the numerical results are compared to the experimental data obtained from testing of the neat and the nanoreinforced epoxy resin.

scholarly journals Effects of the Shape of the Foil Corners on the Irradiation Performance of U10Mo Alloy Based Monolithic Mini-Plates

2015 ◽  
Author(s):  
Hakan Ozaltun ◽  
Pavel Medvedev
Keyword(s):  
High Performance ◽  
Mechanical Response ◽  
Mechanical Performance ◽  
Behavioral Model ◽  
High Density ◽  
Thickness Variation ◽  
Stress Strain ◽  
Operational Variables ◽  
Irradiation Performance ◽  
Fuel Elements

Monolithic plate-type fuel is a fuel form being developed for high performance research and test reactors to minimize the use of enriched material. These fuel elements are comprised of a high density, low enrichment, U-Mo alloy based fuel foil, sandwiched between Zirconium liners and encapsulated in Aluminum cladding. The use of a high density fuel in a foil form presents a number of fabrication and operational concerns, such as: foil centering, flatness of the foil, fuel thickness variation, geometrical tilting, foil corner shape etc. To benchmark this new design, effects of various geometrical and operational variables on irradiation performance have been evaluated. As a part of these series of sensitivity studies, the shape of the foil corners were studied. To understand the effects of the corner shapes of the foil on thermo-mechanical performance of the plates, a behavioral model was developed for a selected plate from RERTR-12 experiments (Plate L1P785). Both fabrication and irradiation processes were simulated. Once the thermo-mechanical behavior the plate is understood for the nominal case, the simulations were repeated for two additional corner shapes to observe the changes in temperature, displacement and stress-strain fields. The results from the fabrication simulations indicated that the foil corners do not alter the post-fabrication stress-strain magnitudes. Furthermore, the irradiation simulations revealed that post-fabrication stresses of the foil would be relieved very quickly in operation. While, foils with chamfered and filleted corners yielded stresses with comparable magnitudes, they are slightly lower in magnitudes, and provided a more favorable mechanical response compared with the foil with sharp corners.

scholarly journals Polymer/Iron-Based Layered Double Hydroxides as Multifunctional Wound Dressings

Pharmaceutics ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1130
Author(s):  
Mariana Pires Figueiredo ◽  
Ana Borrego-Sánchez ◽  
Fátima García-Villén ◽  
Dalila Miele ◽  
Silvia Rossi ◽  
...  
Keyword(s):  
Drug Release ◽  
High Performance ◽  
Mechanical Performance ◽  
Release Kinetics ◽  
Wound Dressings ◽  
In Vitro Drug Release ◽  
Improved Performance ◽  
Double Hydroxide ◽  
Double Hydroxides

This work presents the development of multifunctional therapeutic membranes based on a high-performance block copolymer scaffold formed by polyether (PE) and polyamide (PA) units (known as PEBA) and layered double hydroxide (LDH) biomaterials, with the aim to study their uses as wound dressings. Two LDH layer compositions were employed containing Mg2+ or Zn2+, Fe3+ and Al3+ cations, intercalated with chloride anions, abbreviated as Mg-Cl or Zn-Cl, or intercalated with naproxenate (NAP) anions, abbreviated as Mg-NAP or Zn-NAP. Membranes were structurally and physically characterized, and the in vitro drug release kinetics and cytotoxicity assessed. PEBA-loading NaNAP salt particles were also prepared for comparison. Intercalated NAP anions improved LDH–polymer interaction, resulting in membranes with greater mechanical performance compared to the polymer only or to the membranes containing the Cl-LDHs. Drug release (in saline solution) was sustained for at least 8 h for all samples and release kinetics could be modulated: a slower, an intermediate and a faster NAP release were observed from membranes containing Zn-NAP, NaNAP and Mg-NAP particles, respectively. In general, cell viability was higher in the presence of Mg-LDH and the membranes presented improved performance in comparison with the powdered samples. PEBA containing Mg-NAP sample stood out among all membranes in all the evaluated aspects, thus being considered a great candidate for application as multifunctional therapeutic dressings.

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