Influence of thermal ageing conditions on the properties of cross-linked polyethylene

2006 ◽  
Vol 31 (5) ◽  
pp. 571-582 ◽  
Author(s):  
Yacine Mecheri ◽  
Abdellah Medjoub ◽  
Ahmed Boubakeur ◽  
Mahmoud Boumerzoug
Keyword(s):  
Thermal Ageing

Copper to Aluminum Bonding: IMC Characterization through New Mechanical Sectioning Methods

2010 ◽  
Author(s):  
Lucas Copeland ◽  
Mukul Saran
Keyword(s):  
Intermetallic Compound ◽  
Imaging Study ◽  
Thermal Ageing ◽  
Initial Model ◽  
Growth Morphology ◽  
Intermetallic Formation ◽  
Imaging Parameters ◽  
Bonded Interface ◽  
Bond Interface ◽  
Sem Imaging

Abstract This paper presents a mechanical cross-sectioning approach that produces an image clarity not yet demonstrated in published literature. It demonstrates how a critical sequence of polishing, basic slurry optimization and staining, in conjunction with correct imaging parameters can be used to highlight the growth morphology of the intermetallic compound (IMCs). Utilizing this approach, the paper describes the results of a SEM imaging study of the intermetallic formation and growth at the Cu-Al bond interface during thermal ageing for up to 4000hrs at 150 deg C. The paper uses direct SEM imaging to catalog observations which are used to create an initial model for IMC and void growth at the wire bonded interface. It examines the effect of aluminum splash and concludes that growth of intermetallics at the Cu-Al interface is rapid into the bond-pad aluminum than into the Cu-ball, but the growth thickness uniformity is much higher into the Cu-ball.

Thermal Ageing of Some Insulating Fluids in Contact with Insulation Paper and Copper

2018 ◽  
Vol 68 (12) ◽  
pp. 2881-2885
Author(s):  
Iosif Lingvay ◽  
Gabriela Oprina ◽  
Livia Carmen Ungureanu ◽  
Alexandra Pica ◽  
Valerica Stanoi
Keyword(s):  
Experimental Data ◽  
Dissolved Oxygen ◽  
Copper Foil ◽  
Atmospheric Oxygen ◽  
Thermal Ageing ◽  
Dissolved Oxygen Concentration ◽  
Mineral Oils ◽  
Synthetic Ester ◽  
Cu2o Film ◽  
Transformer Oils

The behaviour of copper and insulation paper in various electrical insulating fluids (transformer oils) exposed to thermal ageing at 110�30C for 1000 hours in closed vessels (without access to atmospheric oxygen) has been studied. The processing of the comparative experimental data revealed in all cases that the concentration of dissolved oxygen in the investigated oils decreases exponentially during the heat treatment. In the presence of the copper foil, the oxygen is almost depleted (the dissolved oxygen concentration is approaching zero), indicating a higher affinity of the copper to oxygen than the affinity to oxygen of the investigated oils. In the presence of the copper foil and / or of the insulation paper, the degradation processes of the mineral oils have a pronounced character, explained by the catalytic activity of the Cu2O film that has been formed and by the paper degradation, respectively. A high thermo-oxidative stability was noticed in the case of natural triglyceride oils, particularly for the synthetic ester-based oil.

scholarly journals Chemical stability of oil-infused polyethylene

2020 ◽  
pp. 088532822097735
Author(s):  
Fedra P Zaribaf ◽  
Harinderjit S Gill ◽  
Elise C Pegg
Keyword(s):  
Vitamin E ◽  
Chemical Stability ◽  
Antioxidant Properties ◽  
Oxidation Stability ◽  
Thermal Ageing ◽  
Similar Process ◽  
Mechanical Degradation ◽  
Suitable Material ◽  
Thermally Treated

Ultra-high molecular weight polyethylene (UHMWPE) can be made radiopaque for medical imaging applications through the diffusion of an iodised oil-based contrast agent (Lipiodol Ultra Fluid). A similar process is used for Vitamin E incorporated polyethylene which provides antioxidant properties. This study aimed to investigate the critical long-term properties of oil-infused medical polyethylene after 4 weeks of accelerated thermal ageing. Samples treated with an oil (Vitamin E or Lipiodol) had a higher oxidation stability than currently used medical grade polyethylene, indicated by a smaller increase in oxidation index after ageing (Vitamin E + 36%, Lipiodol +40%, Untreated +136%, Thermally treated +164%). The tensile properties of oil treated polyethylene after ageing were significantly higher than the Untreated and Thermally treated controls (p<0.05) indicating less mechanical degradation. There was also no alteration in the percentage crystallinity of oil treated samples after ageing, though the radiopacity of the Lipiodol treated samples reduced by 54% after ageing. The leaching of oil with time was also investigated; the leaching of Lipiodol and Vitamin E followed the same trend and reached a steady state by two weeks. Overall, it can be concluded that the diffusion of an oil-based fluid into polyethylene not only increases the oxidative and chemical stability of polyethylene but also adds additional functionality (e.g. radiopacity) providing a more suitable material for long–term medical applications.

The rheological behaviour and thermal ageing characteristics of PP/MWCNT/glass fibre multiscale composites

2021 ◽  
pp. 096739112199290
Author(s):  
N Rasana ◽  
K Jayanarayanan ◽  
Krishna Prasad Rajan ◽  
Aravinthan Gopanna
Keyword(s):  
Hybrid Composites ◽  
Rheological Behaviour ◽  
Strain Energy Release ◽  
Critical Stress Intensity Factor ◽  
Thermal Ageing ◽  
Multiwalled Carbon ◽  
Weight Percentage ◽  
Fixed Weight ◽  
Multiscale Composite ◽  
The Matrix

Multiscale hybrid composites were prepared using varying weight percentages (0 to 5) of multiwalled carbon nanotubes (MWCNTs) as nanofiller and a fixed weight percentage (20) of short glass fibres as micro filler (in polypropylene (PP) matrix. The shear and extensional viscosity of the composites was measured using a capillary rheometer. It was observed that even at higher shear rates the synergism of micro and nanofillers in the matrix significantly enhanced the melt viscosity. The complex nanotube network entanglement with micro fillers and PP chains imparted restrictions to the polymer chain movements. The prepared samples were subjected to thermal ageing at 100°C for 4 days in hot air oven. After ageing, multiscale composite with 3 wt% MWCNTs exhibited 28.57% enhancement in strain at break, whereas the tensile strength and modulus reduced by 6.8% and 8% respectively. The fracture toughness properties like strain energy release rate and critical stress intensity factor were not affected for multiscale composite at the optimum content of 3 wt% MWCNT, even after thermal ageing.

scholarly journals Effect of thermal ageing and deformation on microstructural evolution of 304 and 202 grade steel

2020 ◽  
Author(s):  
Sourabh Shukla ◽  
Awanikumar P. Patil ◽  
Ashlesha P. Kawale ◽  
Sushil Kumar Singh ◽  
Manish A. Thombre
Keyword(s):  
Microstructural Evolution ◽  
Thermal Ageing ◽  
Grade Steel

scholarly journals Towards Improving the Durability and Overall Performance of PV-ETICS by Application of a PCM Layer

2021 ◽  
Vol 11 (10) ◽  
pp. 4667
Author(s):  
Dariusz Heim ◽  
Anna Wieprzkowicz ◽  
Dominika Knera ◽  
Simo Ilomets ◽  
Targo Kalamees ◽  
...  
Keyword(s):  
Power Flow ◽  
Thermal Stabilization ◽  
Thermal Ageing ◽  
Electricity Production ◽  
Latent Heat Storage ◽  
Local Climate ◽  
Building Performance Simulation ◽  
Building Integrated Photovoltaics ◽  
Pv Panel ◽  
Overall Performance

The main goal of the paper was to numerically analyse the risk of overheating of the Energy Activated External Thermal Insulation Composite System (En-ActivETICS) as an example of Building Integrated Photovoltaics (BIPV). The analyses were conducted with the coupled power flow method (thermal and electrical) for 20 European cities. All locations were analysed considering the local climate in the context of building performance simulation as well as electricity production. The obtained results allowed for the determination of the risk of overheating, which can influence system durability, accelerated thermal ageing, and overall performance. It was revealed that the risk of overheating above 80 °C is possible in almost all locations; however, the intensity considerably differs between southern and northern Europe. The effect of latent heat storage for better thermal stabilization and overall performance was determined numerically for all locations. Finally, the improved solution with a phase change material (PCM) layer beside the PV panel was proposed individually for specific climatic zones, considering the required heat capacity. The maximum panel temperature for improved En-ActivETICS does not exceed 85 °C for any location.

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