Experimental study of polymethyl methacrylate: damage under corona discharge

2018 ◽  
Vol 82 (3) ◽  
pp. 31301
Author(s):  
Nora Kireche ◽  
Sébastien Rondot ◽  
Ferroudja Bitam-Megherbi ◽  
Omar Jbara ◽  
Mickael Gilliot ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Corona Discharge ◽  
Polymethyl Methacrylate ◽  
Electron Irradiation ◽  
Degradation Mechanism ◽  
Dielectric Behavior ◽  
Chemical Degradation ◽  
Surface Damages ◽  
Scanning Electron

In high-voltage applications, insulators may be exposed to corona discharges during long periods. In this experimental work, corona discharge tests of different durations are carried out in air at atmospheric pressure on polymethyl methacrylate (PMMA) samples. The resulting surface degradation is studied with several techniques. The surface damages are observed with environmental scanning electron microscope and atomic force microscopy. The results show that electrical trees occur on the surface of material and their distribution depends on the corona discharge duration. The chemical changes on PMMA surface are analyzed by Fourier transform infrared spectroscopy and a chemical degradation mechanism is proposed. Evolution of surface resistivity with corona aging is also implemented by using a classical I(V) method. In addition, to study the dielectric behavior of PMMA, the monitoring of kinetics of the trapped charge under electron irradiation in a scanning electron microscope is performed. The charging ability of PMMA under electron irradiation and its time constant of charging decrease with electrical aging.

Temperature effect on dielectric behavior of an industrial porcelain-type ceramic

2009 ◽  
Vol 87 (9) ◽  
pp. 973-980
Author(s):  
O. Hachicha ◽  
N. Ghorbel ◽  
A. Kallel ◽  
Z. Fakhfakh
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Charge Trapping ◽  
Dielectric Behavior ◽  
Mirror Image ◽  
Induced Current ◽  
Physical Mechanisms ◽  
Motion Process ◽  
Influence Of Temperature On ◽  
Scanning Electron

For a better understanding of the physical mechanisms involved in insulators submitted to electron irradiation inside a scanning electron microscope, it is important to investigate charge trapping and detrapping. The commonly used technique to deduce the trapping ability and the motion process of electric charges is based on two complementary experimental methods: the scanning electron microscope mirror effect (SEMME) and the induced current measurement (ICM). In this paper, our study is devoted to the influence of temperature on the behavior of porcelain materials during electron injection time. To evaluate the geometry of the trapped charge distribution, a detailed analysis using the mirror image formation and its evolution is developed.

Synthesize and Characterization Zr-Al-Si Post through Eggshell Membrane Strengthening with PMMA Matrix

2016 ◽  
Vol 696 ◽  
pp. 85-88
Author(s):  
Niko Eka Putra ◽  
Yosa Fendra ◽  
Denny Nurdin ◽  
Bambang Sunendar Purwasasmita
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Polymethyl Methacrylate ◽  
Sol Gel ◽  
Eggshell Membrane ◽  
Gel Method ◽  
Sol Gel Method ◽  
Three Point Bending ◽  
Hardness Tester ◽  
Scanning Electron

Zr-Al-Si posts were successfully synthesized using biotemplate of eggshell membrane by sol-gel method and strengthening with matrix of polymethyl methacrylate (PMMA). The dental posts made were analyzed with the scanning electron microscope (SEM), three point bending and microvickers hardness tester. There are two methods used to synthesized Zr-Al-Si posts, with calcination and without calcination. The synthesized mechanism is discussed here.

Molecular Interdiffusion of Hauling Theory between Dissimilar Polymers Based on Novel USW

2011 ◽  
Vol 221 ◽  
pp. 289-294 ◽  
Author(s):  
Guo Hong Zhang ◽  
Jian Hui Qiu ◽  
Liang Shao ◽  
Xie Fu
Keyword(s):  
Tensile Strength ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Polymethyl Methacrylate ◽  
Polymer Chains ◽  
The Novel ◽  
Welding Strength ◽  
Reptation Theory ◽  
Scanning Electron

Based on the novel USW method, the welds of Polylactide (PLA) - Polyformaldehyde (POM) and PLA - polymethyl methacrylate (PMMA) have been carried out. The interdiffusion processes of polymer chains have also been investigated according to the reptation theory and the hauling theory. The welding strengths are carried out by the universal tester and the rupture interfaces are observed using the scanning electron microscope. The best welding strength is 52MPa (90% compared with PLA of the PLA-POM system), which can reach the tensile strength of IPS. The molecules of POM are much easier to inter-diffuse than those of PLA and PMMA.

scholarly journals Direct electron irradiation of DNA in a fully aqueous environment. Damage determination in combination with Monte Carlo simulations

2017 ◽  
Vol 19 (3) ◽  
pp. 1798-1805 ◽  
Author(s):  
Marc Benjamin Hahn ◽  
Susann Meyer ◽  
Maria-Astrid Schröter ◽  
Harald Seitz ◽  
Hans-Jörg Kunte ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Monte Carlo Simulations ◽  
Electron Irradiation ◽  
Plasmid Dna ◽  
Aqueous Environment ◽  
Scanning Electron

We report on a study in which plasmid DNA in water was irradiated with 30 keV electrons generated by a scanning electron microscope and passed through a 100 nm thick Si3N4 membrane.

scholarly journals Evaluation of Porosity and Water Sorption in Conventionally Cured Modified Polymethyl Methacrylate Resin - An In Vitro Study

2021 ◽  
Vol 10 (13) ◽  
pp. 930-934
Author(s):  
Merin Mathew ◽  
Kamalakanth Shenoy ◽  
Ravishankar K. S.
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Polymethyl Methacrylate ◽  
Polymer Composite ◽  
Glass Fibre ◽  
Water Sorption ◽  
Control Group ◽  
Fibre Reinforcement ◽  
Sorption Rate ◽  
Scanning Electron

BACKGROUND Dimensional change and porosity in the polymethylmethacrylate based prosthesis affects its clinical performance. Hence, the present study aimed to evaluate the porosity and water sorption present in the modified polymethyl methacrylate polymer composite. METHODS Control group without fibre reinforcement and test groups with fibre reinforcement were prepared for the study. Three different fibres such as boron free-E glass fibre, untreated and plasma-treated polypropylene fibres in varying weight percentage and aspect ratio were considered for reinforcement. The porosity of the fractured surface was observed through a scanning electron microscope (scanning electron microscope) and sorption measured based on international standards organization (ISO) 1567:1999. RESULTS Control group exhibited porous structures, whereas all fibre-reinforced groups did not exhibit porous structure at the fracture surface. There was a significant difference in the sorption rate between control and test group (p < 0.001). Among fibrereinforced test groups, boron free E glass fibre reinforced polymethylmethacrylate exhibited maximum sorption followed by polypropylene fibre reinforced polymer test groups (p < 0.001). However, all samples showed sorption rate within the ISO specification. CONCLUSIONS Fiber reinforcement is an effective method to reduce porosity and water sorption in polymethylmethacrylate based polymer composite regardless of the fibre type. KEY WORDS Polymer Composite, Porosity, Water Sorption, Fiber Reinforcement, Polymethylmethacrylate

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