Effects of Acid Treatment on The Recovery of Outdated Pre-preg Composite Fibers

2021 ◽  
Author(s):  
Zaara Ali ◽  
Eylem Asmatulu
Keyword(s):  
Carbon Fiber ◽  
Glass Fiber ◽  
Acid Treatment ◽  
High Performance ◽  
Treatment Time ◽  
Surface Damage ◽  
Chemical Recycling ◽  
Composite Fibers ◽  
Wide Range ◽  
Different Temperatures

Abstract Purpose Carbon fiber, Kevlar® fiber, and glass fiber are the most widely used polymer prepregs in manufacturing high-performance composites to produce vital parts for a wide range of applications. The production of carbon and Kevlar® fibers is an energy-intensive process, requiring 198–595 MJ to produce 1 kg of virgin carbon fiber. However, chemically recycling these expired prepregs takes only 38.4 MJ/kg, which could be significantly sustainable. The work described in this study involves an array of experiments involving acid treatment of outdated prepreg composite fibers to study its effects and reclaim the fibers for future applications.Method The experiments were carried out at two different temperatures: 25°C and also 60°C. Sulfuric acid, nitric acid, acetone, and distilled water were used in the process, with varying treatment times of 60, 120, 240, 360, and 420 seconds. The recovered fibers were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Result The optimum treatment time and temperature were different for all three types of fibers. Initially, the glass fiber yielded promising results at room temperature and with a minimal 120-s processing time. Carbon fiber treatment was successful at 60°C with a 420-s treatment time. However, some surface damage was observed in the Kevlar® fiber at 60°C. Conclusion The chemical recycling process is the most sustainable, energy- and cost-efficient approach compared to all other available recycling processes. Also, it is possible to recover much cleaner fibers with the weave intact with an acid treatment and solvent-based recovery.

CMP Compatibility of Partially Cured Benzocyclobutene (BCB) for a Via-First 3D IC Process

2005 ◽  
Vol 867 ◽  
Author(s):  
J. J. McMahon ◽  
F. Niklaus ◽  
R. J. Kumar ◽  
J. Yu ◽  
J.Q. Lu ◽  
...  
Keyword(s):  
High Performance ◽  
Removal Rate ◽  
Three Dimensional ◽  
Surface Damage ◽  
Wafer Level ◽  
Razor Blade ◽  
3D Ic ◽  
3D Technology ◽  
Process Step ◽  
Wide Range

AbstractWafer-level three dimensional (3D) IC technology offers the promise of decreasing RC delays by reducing long interconnect lines in high performance ICs. This paper focuses on a viafirst 3D IC platform, which utilizes a back-end-of-line (BEOL) compatible damascene-patterned layer of copper and Benzocyclobutene (BCB). This damascene-patterned copper/BCB serves as a redistribution layer between two fully fabricated wafer sets of ICs and offers the potential of high bonding strength and low contact resistance for inter-wafer interconnects between the wafer pair. The process would thus combine the electrical advantages of 3D technology using Cu-to-Cu bonding with the mechanical advantages of 3D technology using BCB-to-BCB bonding.In this work, partially cured BCB has been evaluated for copper damascene patterning using commercially available CMP slurries as a key process step for a via-first 3D process flow. BCB is spin-cast on 200 mm wafers and cured at temperatures ranging from 190°C to 250°C, providing a wide range of crosslink percentage. These films are evaluated for CMP removal rate, surface damage (surface scratching and embedded abrasives), and planarity with commercially available copper CMP slurries. Under baseline process parameters, erosion, and roughness changes are presented for single-level damascene test patterns. After wafers are bonded under controlled temperature and pressure, the bonding interface is inspected optically using glass-to-silicon bonded wafers, and the bond strength is evaluated by a razor blade test.

A comparative study of mechanical and machining performance of polymer hybrid and carbon fiber epoxy composite materials

2021 ◽  
pp. 096739112110206
Author(s):  
A Tamer Erturk ◽  
Eser Yarar ◽  
Fahri Vatansever ◽  
Alp Eren Sahin ◽  
Mert Kilinçel ◽  
...  
Keyword(s):  
Composite Materials ◽  
Carbon Fiber ◽  
Glass Fiber ◽  
High Performance ◽  
Cost Effective ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Machining Performance ◽  
Polymer Hybrid ◽  
Carbon Fiber Epoxy

Fiber-reinforced plastics are known as advanced composite materials thanks to their high strength and lightweight features. Carbon fiber reinforced polymers (CFRPs) are one of the high-performance and high-cost fiber-reinforced polymer (FRPs) materials. They are used in several high-performance engineering applications such as motorsports, marine, aviation, energy and defense industry. The cost of carbon fiber is higher compared to many other materials, more competitive and cost-effective productions will spur the demand for composite parts exponentially. Thus, hybrid laminate composite containing carbon and glass fiber materials were manufactured as an alternative for CFRP materials. Because using glass fiber prepreg instead of carbon fiber prepreg will lead the material to become cheaper. However, machining of the FRP materials is still an important issue. For this reason, the present study is focused on the mechanical and machining performance of the polymer hybrid and carbon fiber epoxy composites.

Thermal Characterization of IM7/8552-1 Carbon-Epoxy Composites

2014 ◽  
Author(s):  
Messiha T. Saad ◽  
Sandi G. Miller ◽  
Torrence Marunda
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Carbon Fiber ◽  
Specific Heat ◽  
High Performance ◽  
Critical Role ◽  
Flash Method ◽  
Handling Characteristics ◽  
Wide Range

Thermal properties of composite materials such as, thermal conductivity, diffusivity, and specific heat are very important in engineering design process and analysis of aerospace vehicles as well as space systems. These properties are also important in power generation, transportation, and energy storage devices including fuel cells. Thermal conductivity is the property that determines the working temperature levels of the material; it plays a critical role in the performance of materials in high temperature applications, and it is an important parameter in problems involving heat transfer and thermal structures. The objective of this paper is to develop a thermal properties data base for the carbon fiber-epoxy (IM7/8552-1) composite. The IM7 carbon fiber is a continuous, high performance, intermediate modulus, PAN based fiber. This fiber has been surface treated and can be sized to improve its interlaminar shear properties, handling characteristics, and structural properties. The 8552 is a high performance tough epoxy matrix for use in primary aerospace structures. It exhibits good impact resistance and damage tolerance for a wide range of applications. The IM7/8552-1 is an amine cured unidirectional prepreg. The manufacturer recommended cure cycle for this material was followed, which includes consolidation under vacuum and autoclave pressure. The composite has a service temperature up to 121°C (250°F). The thermal properties of IM7/8552-1 carbon-epoxy have been investigated using experimental methods. The flash method was used to measure the thermal diffusivity of the composite. This method is based on the American Society for Testing and Materials standard, ASTM E1461. In addition, the Differential Scanning Calorimeter was used in accordance with the ASTM E1269 standard to measure the specific heat. The measured thermal diffusivity, specific heat, and density data were used to compute the thermal conductivity of the IM7/8552-1 carbon-epoxy composite.

scholarly journals ZEÓLITA NaA SINTETIZADA SOBRE FIBRA DE VIDRO COMO ESTRATÉGIA PARA OTIMIZAÇÃO DO ABRANDAMENTO DE ÁGUAS DURAS

Química Nova ◽  
2021 ◽  
Author(s):  
Edipo Oliveira ◽  
Conceição Alves ◽  
Antonia França ◽  
Ronaldo Nascimento ◽  
José Sasaki ◽  
...  
Keyword(s):  
Glass Fiber ◽  
High Performance ◽  
Fiber Surface ◽  
Hard Water ◽  
Complete Removal ◽  
Alkaline Treatment ◽  
Water Softening ◽  
Wide Range ◽  
Zeolite Naa ◽  
Softening Process

NaA ZEOLITE SYNTHESIZED OVER FIBERGLASS AS A STRATEGY FOR OPTIMIZING HARD WATER SOFTENING. Zeolite NaA has been successfully synthesized over glass fiber surface previously activated by alkaline treatment. By varying the time of the treatment and the amount of silica and alumina precursors used in the reaction mixture, a sample with higher zeolite concentration could be obtained. This material was evaluated for water softening process as an alternative substitute for the use of the zeolite in its powder form, in which several drawbacks related to recovery and reuse limit its application. Water softening experiments, carried out in a continuous flow system, with a column containing the glass fiber-zeolite NaA, showed high performance in decreasing the Ca2+ ions, with complete removal achieved for 20 mL of simulated hard water (Ca2+ 100.0 mg L– ¹) by using 200 mg of the sample in form of column (10 mm diameter × 300 mm high). The sample maintained this performance in a wide range of pH (3.0-9.0), and also presented a feasible regenerability, with no decrease in its performance during the first four cycles of use, reaching 87.3% of efficiency over the tenth cycle.

Microstructure of sputter deposited Ni-Sb ohmic contacts on GaAs

1989 ◽  
Vol 47 ◽  
pp. 450-451
Author(s):  
S. Yegnasubramanian ◽  
V.C. Kannan ◽  
R. Dutto ◽  
P.J. Sakach
Keyword(s):  
High Performance ◽  
Ohmic Contacts ◽  
Surface Defects ◽  
Pure Metal ◽  
Device Fabrication ◽  
Native Oxide ◽  
Metal Thin Films ◽  
Recent Developments ◽  
Different Temperatures ◽  
Sputter Deposited

Recent developments in the fabrication of high performance GaAs devices impose crucial requirements of low resistance ohmic contacts with excellent contact properties such as, thermal stability, contact resistivity, contact depth, Schottky barrier height etc. The nature of the interface plays an important role in the stability of the contacts due to problems associated with interdiffusion and compound formation at the interface during device fabrication. Contacts of pure metal thin films on GaAs are not desirable due to the presence of the native oxide and surface defects at the interface. Nickel has been used as a contact metal on GaAs and has been found to be reactive at low temperatures. Formation Of Ni2 GaAs at 200 - 350C is reported and is found to grow epitaxially on (001) and on (111) GaAs, but is shown to be unstable at 450C. This paper reports the investigations carried out to understand the microstructure, nature of the interface and composition of sputter deposited and annealed (at different temperatures) Ni-Sb ohmic contacts on GaAs by TEM. Attempts were made to correlate the electrical properties of the films such as the sheet resistance and contact resistance, with the microstructure. The observations are corroborated by Scanning Auger Microprobe (SAM) investigations.

Validated Stability Indicating HPTLC Method for the Estimation of Amoxapine in Different Stress Conditions

2019 ◽  
Vol 15 (3) ◽  
pp. 273-279
Author(s):  
Shweta G. Rangari ◽  
Nishikant A. Raut ◽  
Pradip W. Dhore
Keyword(s):  
High Performance ◽  
Limit Of Detection ◽  
Degradation Products ◽  
Analysis Data ◽  
Peak Height ◽  
Good Resolution ◽  
Stability Indicating ◽  
Limit Of Quantitation ◽  
Wide Range ◽  
Hptlc Method

Background:The unstable and/or toxic degradation products may form due to degradation of drug which results into loss of therapeutic activity and lead to life threatening condition. Hence, it is important to establish the stability characteristics of drug in various conditions such as in temperature, light, oxidising agent and susceptibility across a wide range of pH values.Introduction:The aim of the proposed study was to develop simple, sensitive and economic stability indicating high performance thin layer chromatography (HPTLC) method for the quantification of Amoxapine in the presence of degradation products.Methods:Amoxapine and its degraded products were separated on precoated silica gel 60F254 TLC plates by using mobile phase comprising of methanol: toluene: ammonium acetate (6:3:1, v/v/v). The densitometric evaluation was carried out at 320 nm in reflectance/absorbance mode. The degradation products obtained as per ICH guidelines under acidic, basic and oxidative conditions have different Rf values 0.12, 0.26 and 0.6 indicating good resolution from each other and pure drug with Rf: 0.47. Amoxapine was found to be stable under neutral, thermal and photo conditions.Results:The method was validated as per ICH Q2 (R1) guidelines in terms of accuracy, precision, ruggedness, robustness and linearity. A good linear relationship between concentration and response (peak area and peak height) over the range of 80 ng/spot to 720 ng/spot was observed from regression analysis data showing correlation coefficient 0.991 and 0.994 for area and height, respectively. The limit of detection (LOD) and limit of quantitation (LOQ) for area were found to be 1.176 ng/mL and 3.565 ng/mL, whereas for height, 50.063 ng/mL and 151.707 ng/mL respectively.Conclusion:The statistical analysis confirmed the accuracy, precision and selectivity of the proposed method which can be effectively used for the analysis of amoxapine in the presence of degradation products.

Phytochemical, Analytical and Medicinal Studies of Holoptelea integrifolia Roxb. Planch - A Review

2019 ◽  
Vol 5 (4) ◽  
pp. 270-277 ◽  
Author(s):  
Vijay Kumar ◽  
Simranjeet Singh ◽  
Ragini Bhadouria ◽  
Ravindra Singh ◽  
Om Prakash
Keyword(s):  
Liquid Chromatography ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
High Performance ◽  
Biologically Active ◽  
Toxicological Studies ◽  
Wide Range ◽  
Layer Chromatography

Holoptelea integrifolia Roxb. Planch (HI) has been used to treat various ailments including obesity, osteoarthritis, arthritis, inflammation, anemia, diabetes etc. To review the major phytochemicals and medicinal properties of HI, exhaustive bibliographic research was designed by means of various scientific search engines and databases. Only 12 phytochemicals have been reported including biologically active compounds like betulin, betulinic acid, epifriedlin, octacosanol, Friedlin, Holoptelin-A and Holoptelin-B. Analytical methods including the Thin Layer Chromatography (TLC), High-Performance Thin Layer Chromatography (HPTLC), High-Performance Liquid Chromatography (HPLC) and Liquid Chromatography With Mass Spectral (LC-MS) analysis have been used to analyze the HI. From medicinal potency point of view, these phytochemicals have a wide range of pharmacological activities such as antioxidant, antibacterial, anti-inflammatory, and anti-tumor. In the current review, it has been noticed that the mechanism of action of HI with biomolecules has not been fully explored. Pharmacology and toxicological studies are very few. This seems a huge literature gap to be fulfilled through the detailed in-vivo and in-vitro studies.

Study of Transcrystallization in Polymer Composites

1989 ◽  
Vol 170 ◽  
Author(s):  
Benjamin S. Hsiao ◽  
J. H. Eric
Keyword(s):  
Thermal Conductivity ◽  
Free Energy ◽  
Carbon Fiber ◽  
Plasma Treatment ◽  
Polymer Composites ◽  
High Performance ◽  
Interfacial Strength ◽  
Fiber Surface ◽  
Semicrystalline Polymers ◽  
First Case

AbstractTranscrystallization of semicrystalline polymers, such as PEEK, PEKK and PPS, in high performance composites has been investigated. It is found that PPDT aramid fiber and pitch-based carbon fiber induce a transcrystalline interphase in all three polymers, whereas in PAN-based carbon fiber and glass fiber systems, transcrystallization occurs only under specific circumstances. Epitaxy is used to explain the surface-induced transcrystalline interphase in the first case. In the latter case, transcrystallization is probably not due to epitaxy, but may be attributed to the thermal conductivity mismatch. Plasma treatment on the fiber surface showed a negligible effect on inducing transcrystallization, implying that surface-free energy was not important. A microdebonding test was adopted to evaluate the interfacial strength between the fiber and matrix. Our preliminary results did not reveal any effect on the fiber/matrix interfacial strength of transcrystallinity.

scholarly journals RELaTED Project: New Developments on Ultra-Low Temperature District Heating Networks

Proceedings ◽  
2020 ◽  
Vol 65 (1) ◽  
pp. 25
Author(s):  
Antonio Garrido Marijuan ◽  
Roberto Garay ◽  
Mikel Lumbreras ◽  
Víctor Sánchez ◽  
Olga Macias ◽  
...  
Keyword(s):  
Low Temperature ◽  
High Performance ◽  
Waste Heat ◽  
District Heating ◽  
Hot Water ◽  
Thermal Systems ◽  
Heating Source ◽  
Wide Range ◽  
Thermal Sources ◽  
Heating Networks

District heating networks deliver around 13% of the heating energy in the EU, being considered as a key element of the progressive decarbonization of Europe. The H2020 REnewable Low TEmperature District project (RELaTED) seeks to contribute to the energy decarbonization of these infrastructures through the development and demonstration of the following concepts: reduction in network temperature down to 50 °C, integration of renewable energies and waste heat sources with a novel substation concept, and improvement on building-integrated solar thermal systems. The coupling of renewable thermal sources with ultra-low temperature district heating (DH) allows for a bidirectional energy flow, using the DH as both thermal storage in periods of production surplus and a back-up heating source during consumption peaks. The ultra-low temperature enables the integration of a wide range of energy sources such as waste heat from industry. Furthermore, RELaTED also develops concepts concerning district heating-connected reversible heat pump systems that allow to reach adequate thermal levels for domestic hot water as well as the use of the network for district cooling with high performance. These developments will be demonstrated in four locations: Estonia, Serbia, Denmark, and Spain.

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