scholarly journals Biodegradable dielectricmaterial using PLA and luffa fiber modified by medical linear accelerator

2021 ◽  
Author(s):  
Sonismita Dalai ◽  
Chhatrapati parida
Keyword(s):  
Dielectric Constant ◽  
Linear Accelerator ◽  
Irradiation Dose ◽  
Natural Fiber ◽  
Agricultural Waste ◽  
Dielectric Behavior ◽  
Poly Lactic Acid ◽  
Medical Linear Accelerator ◽  
Different Temperatures ◽  
Low Irradiation

Abstract Biodegradable electronic devices are presently in command in various sectors mainly in health care system.The present work comprehends the dielectric properties of biodegradable composites made from biodegradable polymer poly (lactic) acid (PLA) and natural fiber of luffa cylindrica (LC) fabricated using microcompounding and injection molding. LC fibers are an agricultural waste, rich in cellulose.LC fibers were exposed to 6 MeV electron beam of doses 0.5Gy, 1.0Gy, 2.0Gy, 4.0Gy and 10.0 Gy generated from medical linear accelerator(LINAC) in presence of air. Such low doses are normally used for treatment of cancer patients and not for modifying polymers where doses in the range of 20-200KGy are used. The effect of such low irradiation dose on fiber and study if any significant changes taking place is the innovative aspect of the present work. The effects of irradiation dose on dielectric behavior such as dielectric constant and ac conductivity were investigated at different temperatures 260C, 40oC, 60oC and 80oC while keeping frequency constant. The increase in dielectric constant from 57 in virgin PLA at 260C,500Hz to a maximum of 84 in composite sample due to reinforcement of low dose irradiated LC fibers recording 49% increase is an important result of the investigation.

scholarly journals Green dielectric solids using PLA and luffa fiber modified by the medical linear accelerator

2021 ◽  
Author(s):  
Sonismita Dalai ◽  
Chhatrapati Parida
Keyword(s):  
Dielectric Constant ◽  
Linear Accelerator ◽  
Irradiation Dose ◽  
Natural Fiber ◽  
Agricultural Waste ◽  
Poly Lactic Acid ◽  
Medical Linear Accelerator ◽  
Different Temperatures ◽  
Dielectric Solids ◽  
Low Irradiation

Abstract Biodegradable electronic devices are presently in command in various sectors mainly in the health care system. The present work comprehends the dielectric properties of biodegradable composites made from biodegradable polymer poly (lactic) acid (PLA) and natural fiber of luffa cylindrical (LC) fabricated using micro compounding and injection molding. LC fibers are agricultural waste, rich in cellulose.LC fibers were exposed to a 6 MeV electron beam of doses 0.5Gy, 1.0Gy, 2.0Gy, 4.0Gy, and 10.0 Gy generated from a medical linear accelerator(LINAC) in presence of air. Such low doses are normally used for the treatment of cancer patients and not for modifying polymers where doses in the range of 20-200KGy are used. The effect of such low irradiation dose on fiber and study if any significant changes taking place is the innovative aspect of the present work. The effects of irradiation dose on dielectric constant and ac conductivity were investigated at different temperatures 260C, 40oC, 60oC, and 80oC while keeping the frequency constant. The increase in dielectric constant from 57 in virgin PLA at 260C,500Hz to a maximum of 84 in the composite sample due to reinforcement of low dose irradiated LC fibers recording a 49% increase is an important result of the investigation.

ON THE DIELECTRIC BEHAVIOR OF LiCo3/5Fe2/5VO4 CERAMICS

2010 ◽  
Vol 24 (07) ◽  
pp. 665-670
Author(s):  
MOTI RAM
Keyword(s):  
Activation Energy ◽  
Dielectric Constant ◽  
Frequency Dependence ◽  
Chemical Method ◽  
Arrhenius Plot ◽  
Dielectric Behavior ◽  
Tangent Loss ◽  
Low Frequencies ◽  
Different Temperatures ◽  
Tan Δ

The LiCo 3/5 Fe 2/5 VO 4 ceramics has been fabricated by solution-based chemical method. Frequency dependence of the dielectric constant (εr) at different temperatures exhibits a dispersive behavior at low frequencies. Temperature dependence of εr at different frequencies indicates the dielectric anomalies in εr at Tc (transition temperature) = 190°C, 223°C, 263°C and 283°C with (εr) max ~ 5370, 1976, 690 and 429 for 1, 10, 50 and 100 kHz, respectively. Frequency dependence of tangent loss ( tan δ) at different temperatures indicates the presence of dielectric relaxation in the material. The value of activation energy estimated from the Arrhenius plot of log (τd) with 103/T is ~(0.396 ± 0.012) eV.

scholarly journals Additive Manufacturing: A Novel Method for Developing an Acoustic Panel Made of Natural Fiber-Reinforced Composites with Enhanced Mechanical and Acoustical Properties

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Vignesh Sekar ◽  
Mohammad Hosseini Fouladi ◽  
Satesh Narayana Namasivayam ◽  
Sivakumar Sivanesan
Keyword(s):  
Additive Manufacturing ◽  
Natural Fiber ◽  
Agricultural Waste ◽  
Natural Fibers ◽  
Poly Lactic Acid ◽  
Synthetic Fibers ◽  
Acoustical Properties ◽  
Biodegradable Composite ◽  
Novel Method ◽  
Almost All

Natural fibers and their composites are being widely used in almost all the applications in this modern era. However, the properties of natural fibers have to be enhanced in order to compete with synthetic fibers. This review paper opens up additive manufacturing, as a novel method for developing an acoustic panel using natural fiber composites with enhanced mechanical and acoustical properties. This approach will help to replace synthetic-based acoustic absorbers with biodegradable composite panels in acoustic applications. This review also covers, poly(lactic acid) as a polymer matrix and its advantages, the available variety of natural fibers as reinforcement in terms of mechanical and acoustical properties. The natural fiber-based filaments used in additive manufacturing and acoustic panels made from the available natural fibers are also elaborated here. This review shows the importance of additive manufacturing and its application to develop novel acoustic panels made of agricultural waste.

scholarly journals Valorization of Hemp Hurds as Bio-Sourced Additives in PLA-Based Biocomposites

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3786
Author(s):  
Sina Momeni ◽  
Muhammad Safder ◽  
Mohammad Abu Hasan Khondoker ◽  
Anastasia Leila Elias
Keyword(s):  
Lactic Acid ◽  
Natural Fiber ◽  
Low Cost ◽  
Agricultural Waste ◽  
Poly Lactic Acid ◽  
Mechanical And Thermal Properties ◽  
Plant Fibers ◽  
Chemical Treatments ◽  
Alkaline Peroxide ◽  
Hemp Hurd

Sourced from agricultural waste, hemp hurds are a low-cost renewable material with high stiffness; however, despite their potential to be used as low-cost filler in natural fiber reinforced polymer biocomposites, they are often discarded. In this study, the potential to add value to hemp hurds by incorporating them into poly(lactic acid) (PLA) biopolymer to form bio-based materials for packaging applications is investigated. However, as with many plant fibers, the inherent hydrophilicity of hemp hurds leads to inferior filler-matrix interfacial interactions, compromising the mechanical properties of the resulting biocomposites. In this study, two chemical treatments, alkaline (NaOH) and alkaline/peroxide (NaOH/H2O2) were employed to treat hemp hurds to improve their miscibility with poly(lactic acid) (PLA) for the formation of biocomposites. The effects of reinforcement content (5, 10, and 15 wt. %), chemical treatments (purely alkaline vs. alkaline/peroxide) and treatment cycles (1 and 3 cycles) on the mechanical and thermal properties of the biocomposites were investigated. The biocomposites of treated hemp hurd powder exhibited enhanced thermal stability in the temperature range commonly used to process PLA (130–180 °C). The biocomposites containing 15 wt. % hemp hurd powder prepared using a single-cycle alkaline/peroxide treatment (PLA/15APHH1) exhibited a Young’s modulus of 2674 MPa, which is 70% higher than that of neat PLA and 9.3% higher than that of biocomposites comprised of PLA containing the same wt. % of untreated hemp hurd powder (PLA/15UHH). Furthermore, the tensile strength of the PLA/15APHH1 biocomposite was found to be 62.6 MPa, which was 6.5% lower than that of neat PLA and 23% higher than that of the PLA/15UHH sample. The results suggest that the fabricated PLA/hemp hurd powder biocomposites have great potential to be utilized in green and sustainable packaging applications.

Microwave wide band absorption by carbon from Corn cob-1

2016 ◽  
Vol 12 (2) ◽  
pp. 4204-4212 ◽  
Author(s):  
Maheshwar Sharon ◽  
Ritesh Vishwakarma ◽  
Abhijeet Rajendra Phatak ◽  
Golap Kalita ◽  
Nallin Sharma ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Agricultural Waste ◽  
Wide Band ◽  
Nickel Nitrate ◽  
Equivalent Amount ◽  
Frequency Range ◽  
Corn Cob ◽  
Different Temperatures ◽  
Band Absorption ◽  
5 Ghz

Corn cob, an agricultural waste, is paralyzed at different temperatures (700oC, 800oC and 900oC). Microwave absorption of carbon in the frequency range of 2 GHz to 8 GHz is reported. Carbon activated  with 5%  nickel nitrate showed more than 90% absorption of microwave in the frequency range from 6 GHz to 8 GHz, while carbon activated  with 10% Nickel nitrate treated corn cob showed 90% absorption  in the frequency range of 2.5 GHz to 5 GHz. Carbon showing the best absorption are characterized by XRD, Raman spectra and SEM . It is suggested that corn cob treatment   alone with KOH did not improve the microwave absorption, whereas treatment along with nickel nitrate improved the absorption property much better. It is proposed that treatment with nickel nitrate helps in creating suitable pores in carbon   which improved the absorption behavior because while treating carbon with 1N HCl helps to leach out nickel creating equivalent amount of pores in the carbon.

Influence of Ca-Doping on Structural, Magnetic and Dielectric Properties of Ba3Co2-xCaxFe24O41 Hexaferrite Powders

2015 ◽  
Vol 241 ◽  
pp. 226-236 ◽  
Author(s):  
Neha Solanki ◽  
Rajshree B. Jotania
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Sol Gel ◽  
Calcium Content ◽  
Combustion Method ◽  
Dielectric Behavior ◽  
Dielectric Parameters ◽  
Ca Doping ◽  
Auto Combustion ◽  
Magnetic And Dielectric Properties

Influence of Ca substitution on structural, magnetic and dielectric properties of Ba3Co2-xCaxFe24O41(where x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0), prepared by Sol-Gel auto-combustion method, has been investigated in present studies. The obtained powder was sintered at 950 oC for 4 hrs. in the static air atmosphere. Structural analysis of Ca-doped Ba3Co2-xCaxFe24O41powders revealed pure Z-type hexaferrite phase at low temperature. The frequency dependent dielectric constant (Єʹ) and magnetic properties such as remanent magnetization (Mr), saturation magnetization (Ms) and coercivity (Hc) were studied. It is observed that coercivity increased gradually with increase in calcium content. The real dielectric constant (Єʹ) and dielectric loss tangent (tan δ) were studied in the frequency range of 20Hz to 2MHz. The dielectric parameters for all samples show normal dielectric behavior as observed in hexaferrites. Contents of Paper

scholarly journals Electrical Conduction Mechanism in Solid Polymer Electrolytes: New Concepts to Arrhenius Equation

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Shujahadeen B. Aziz ◽  
Zul Hazrin Z. Abidin
Keyword(s):  
Dielectric Constant ◽  
Polymer Electrolytes ◽  
Conduction Mechanism ◽  
Dc Conductivity ◽  
Solid Polymer Electrolytes ◽  
Solid Polymer ◽  
Arrhenius Behavior ◽  
Different Temperatures ◽  
Solution Cast ◽  
The Fourier Transform

Solid polymer electrolytes based on chitosan NaCF3SO3 have been prepared by the solution cast technique. X-ray diffraction shows that the crystalline phase of the pure chitosan membrane has been partially disrupted. The fourier transform infrared (FTIR) results reveal the complexation between the chitosan polymer and the sodium triflate (NaTf) salt. The dielectric constant and DC conductivity follow the same trend with NaTf salt concentration. The increase in dielectric constant at different temperatures indicates an increase in DC conductivity. The ion conduction mechanism follows the Arrhenius behavior. The dependence of DC conductivity on both temperature and dielectric constant (σdc(T,ε′)=σ0e−Ea/KBT) is also demonstrated.

COMPARATIVE STUDY OF DIELECTRIC BEHAVIOR OF Mn0.4Zn0.6Fe2O4 NANOFERRITE BY CITRATE PRECURSOR METHOD

2008 ◽  
Vol 22 (16) ◽  
pp. 2537-2544 ◽  
Author(s):  
PREETI MATHUR ◽  
ATUL THAKUR ◽  
M. SINGH
Keyword(s):  
Particle Size ◽  
Dielectric Constant ◽  
Comparative Study ◽  
Average Particle Size ◽  
Dielectric Behavior ◽  
Average Particle ◽  
Oxidizing Agent ◽  
Precursor Method ◽  
Citrate Precursor ◽  
Citrate Precursor Method

In the present work, comparative study of the dielectric behavior of Mn 0.4 Zn 0.6 Fe 2 O 4 ferrite synthesized with and without H 2 O 2 (hydrogen peroxide) has been presented. The dc resistivity has been improved by the citrate precursor method as compared to the ceramic method, and it is further improved by the addition of H 2 O 2, which acts as a strong oxidizing agent. We have shown by means of X-ray diffraction that the resulting ferrite is made up of nanocrystallites and the average size of these nanocrystallites–calculated by Scherrer's formula–depends on the polarizer. The average particle size was found to be ~70 nm with H 2 O 2 and ~88 nm without H 2 O 2. The particle size is further confirmed by scanning electron microscopy. Both the results are found to be in good agreement. The decrease in dielectric constant and dielectric loss factor by addition of oxidizing agent is justified by inverse proportionality between the resistivity and dielectric constant. Possible mechanisms contributing to these processes have been discussed.

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