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[IEEE 2018 IEEE 2nd International Conference on Dielectrics (ICD) - Budapest (2018.7.1-2018.7.5)] 2018 IEEE 2nd International Conference on Dielectrics (ICD) - Modelling Charge Generation and Transport in Low Density Polyethylene Irradiated by an Electron-Beam
摘要： One way to bypass charge generation due to injection in an insulator sandwiched between parallel electrodes and submitted to an applied voltage is to implant charges in the material with the help of an electron beam. The electrons position and quantity is theoretically known as long as the beam energy and beam current are known. Low density polyethylene (LDPE) has been characterized with in-situ space charge measurements by pulsed electroacoustic method during irradiation, and with ex-situ measurements while a DC voltage is applied. A fluid charge transport model has been developed using a commercial software, to reproduce the space charge behaviour during and after irradiation. Simulated results during irradiation are first compared to in-situ space charge measurements, in order to validate the model parameters related to e-beam irradiation. Simulations are then performed on post-irradiated samples, polarized under different electric fields. Space charge measurements and current measurements are available for comparison. Simulated results are in relatively good agreement with experimental ones as long as the model parameters are adapted to irradiated low density polyethylene, compared to a best set of parameters adapted uniquely for non-irradiated polyethylene.
关键词： charge generation and transport,fluid model,LDPE,ageing,electron-beam irradiation
更新于2025-09-23 15:22:29
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Effect of Particles Size on Dielectric Properties of Nano-ZnO/LDPE Composites
摘要： The melt blending was used to prepare 3 wt% ZnO/low density polyethylene (ZnO/LDPE) nanocomposites in this article. The effect of different inorganic ZnO particles doping on the dielectrical property and crystal habit of LDPE matrix was explored. The nanoparticles size was 9 nm, 30 nm, 100 nm, and 200 nm respectively. Scanning electron microscope (SEM) was used to characterize ZnO nanoparticles whereas differential scanning calorimetry (DSC) was used to make thermal characterization of the samples. Besides, the AC (alternating current), DC (direct current) breakdown characteristics and electrical conductivity of the nanocomposites was studied in this article. The experimental results showed that nano-ZnO/LDPE composites had the advantages such as small crystal size, high crystallization rate and crystallinity owing to nano-ZnO particles doping, when doping nano-ZnO particles size was 30 nm, the ZnO/LDPE nanocomposite crystallinity crest value 39.77% appeared. At the mean time, the DC and AC breakdown field strength values of composites were 138.0 kV/mm and 340.4 kV/mm respectively. They were the maximal values which improved 8.24% and 13.85% than LDPE. The AC breakdown field strength of samples decreased with specimen thickness increase. The DC breakdown field strength of LDPE and ZnO/LDPE composites were greater than AC breakdown field strength. From the conductivity experimental result it could be seen that when the experimental temperature and electric field intensity rose, the current density and conductivity of ZnO/LDPE composites increased with the enlargement of ZnO particles size. But the values were less than which of LDPE.
关键词： particles size,LDPE,dielectric properties,ZnO
更新于2025-09-23 15:22:29
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Enhanced Visible Light Photodegradation of Microplastic Fragments with Plasmonic Platinum/Zinc Oxide Nanorod Photocatalysts
摘要： Microplastics are persistent anthropogenic pollutants which have become a global concern owing to their widespread existence and unfamiliar threats to the environment and living organisms. This study demonstrates the degradation of fragmented microplastics particularly low-density polyethylene (LDPE) film in water, through visible light-induced plasmonic photocatalysts comprising of platinum nanoparticles deposited on zinc oxide (ZnO) nanorods (ZnO-Pt). The ZnO-Pt nanocomposite photocatalysts were observed to have better degradation kinetics for a model organic dye (methylene blue) compared to bare ZnO nanorods, attributed to the plasmonic effects leading to better interfacial exciton separation and improved hydroxyl radical activity along with a 78% increase in visible light absorption. These demonstrations of the plasmonically enhanced photocatalyst enabled it to effectively degrade microplastic fragments as confirmed following the changes in carbonyl and vinyl indices in infrared absorption. In addition, visual proof of physical surface damage of the LDPE film establishes the efficacy of using plasmonically enhanced nanocomposite photocatalytic materials to tackle the microplastic menace using just sunlight for a clean and green approach towards mitigation of microplastics in the ecosystem.
关键词： microplastics,platinum nanoparticle,ZnO nanorod,LDPE film,visible light photodegradation,nanocomposite
更新于2025-09-16 10:30:52
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Studies on the Properties of Photo/Bio-Degradable Ldpe with Benzophenone and Hydrolysed Starch
摘要： Maize starch was acid hydrolyzed at 50-60?C for 6 hours. Reduced viscosity for raw starch, hydrolyzed starch (HS) and glucose were determined. DSC tests were done to determine the melting point of the modified starch. LDPE of MFI 2 g/10 min was blended with this hydrolyzed starch at various proportions of 3-20% (wt%), photo-degradable additive – benzophenone (3%) and glycerol (3%) as compatibilizer using a twin screw extruder. The formulations made using HS were easy for processing and since the MFI was increased, the starch added, proved to be hydrolyzed, Tubular blown film was extruded using blown film extruder. LDPE with hydrolysed starch are processable into thin films (< 250 microns). The films obtained were tested for various mechanical tests like tensile strength, elongation at break, etc. The mechanical properties like tensile strength and elongation at break were lowered. Tear strength and dart impact strength were lowered. Also accelerated UV weathering and compost biodegradation tests were done on all the samples. Scanning Electron Microscope images were taken before and after UV weathering and also after biodegradation to determine the morphological changes on the samples. The samples were highly photo/biodegradable and hence will not pollute the environment.
关键词： LDPE,Photo/Biodegradation,Benzophenone,Hydrolyzed starch,Mechanical properties
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE 2nd International Conference on Dielectrics (ICD) - Budapest (2018.7.1-2018.7.5)] 2018 IEEE 2nd International Conference on Dielectrics (ICD) - Characterization of LDPE-Metal Oxide Nanocomposites Using Thermo-Analytical and Spectroscopic Techniques
摘要： Polyethylene metal oxide nanocomposites find their application as high voltage insulation for direct current cables, to mitigate the space charge and other issues. Nano particles like SiO2, MgO, ZnO etc are used as filler materials in polyethylene matrix to achieve good electrical and mechanical properties like: space charge reduction, enhanced surface & volume resistivity and higher dielectric stress withstand capabilities. Surface modification of metal particles is usually done by treating the nanoparticles with silane to have good distribution and dispersion of metal particles. However, characterization of nanocomposite based on spectroscopic and thermo-analytical techniques is very essential to understand its long term performance and its reliability when used as insulation in HVDC extruded power cables. Different metal oxide nanoparticles such as MgO and SiO2 have been investigated as fillers in low density polyethylene. The distribution and dispersion of the nanoparticles in the LDPE is determined by SEM (Scanning Electron Microscopy). Kinetic studies were carried out by measuring enthalpy, melting temperature, percentage decomposition using simultaneous thermal analyser. Fourier Infrared spectrometer, X-ray diffractometer and dielectric spectrometer are used for characterization and dielectric response. The results are presented and discussed.
关键词： LDPE,Dielectric response,Polyethylene-metal oxide nanocomposite,HVDC cable insulation
更新于2025-09-09 09:28:46
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TiO <sub/>2</sub> :Sm <sup>3+</sup> based luminescent oxygen sensitive probes in LDPE packaging material
摘要： In present work it was attempted to prepare luminescent TiO2:Sm3+ microprobes embedded into low density polyethylene (LDPE) films for real-time non-intrusive detection of oxygen contamination in plastic film of food packages with a long term goal of streamlining the quality control mechanisms in food packaging process. The luminescence of TiO2:Sm3+ has previously been reported to be a usable for optical sensing of O2 and other gases [1]. In current work we also show that its thermal stability makes it especially suitable for thermo polymer industry as it can withstand required thermal treatments encountered in different polymer processing stages without losing its ability to function as an O2 probe. Sol–gel-prepared TiO2:Sm3+ microparticles were embedded into LDPE by direct mixing [2] and hot pressing the polymer in molten state. The optical response of the doped films to various O2 ambient concentrations are reported in comparison to pristine TiO2:Sm3+ powder. The shortcomings in the sensor performance due to poor oxide particle size control must be paid attention in the future.
关键词： extrusion,LDPE,Sm3+,oxygen sensor,TiO2
更新于2025-09-04 15:30:14