scholarly journals UV-Irradiation Effect on the Photodegradation of Plasticized Poly (Ortho, Meta, and Para-Fluorostyrene) Isomers in Solid Films

2012 ◽  
Vol 4 (5) ◽  
Author(s):  
Khalid E. Al Ani ◽  
Mai Anabtawi
Keyword(s):  
Uv Irradiation ◽  
Irradiation Effect ◽  
Solid Films

scholarly journals Effect of UV Ageing on the fatigue life of bulk polyethylene

2018 ◽  
Vol 165 ◽  
pp. 08002 ◽  
Author(s):  
Hamza Lamnii ◽  
Moussa Nait-Abdelaziz ◽  
Georges Ayoub ◽  
Jean-Michel Gloaguen ◽  
Ulrich Maschke ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Uv Irradiation ◽  
Chemical Structure ◽  
Fatigue Behavior ◽  
Crystalline Polymer ◽  
Fatigue Loading ◽  
Chain Scission ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Irradiation Effect

Polymers operating in various weathering conditions must be assessed for lifetime performance. Particularly, ultraviolet (UV) radiations alters the chemical structure and therefore affect the mechanical and fatigue properties. The UV irradiation alters the polymer chemical structure, which results into a degradation of the mechanical and fatigue behavior of the polymer. The polymer properties degradation due to UV irradiation is the result of a competitive process of chain scission versus post-crosslinking. Although few studied investigated the effect of UV irradiation on the mechanical behaviour of thermoplastics, fewer examined the UV irradiation effect on the fatigue life of polymers. This study focuses on investigating the effect of UV irradiation on the fatigue properties of bulk semi-crystalline polymer; the low density Polyethylene (LDPE). Tensile specimens were exposed to different dose values of UV irradiation then subjected to fatigue loading. The fatigue tests were achieved under constant stress amplitude at a frequency of 1Hz. The results show an important decrease of the fatigue limit with increasing absorbed UV irradiation dose.

scholarly journals ESR Study on the UV-Irradiation Effect of Higher PolyolhydrogenPeroxide Systems

1962 ◽  
Vol 83 (6) ◽  
pp. 652-655 ◽  
Author(s):  
Keiji KUWATA ◽  
Takahisa ICHIKAWA ◽  
Kozo HIROTA
Keyword(s):  
Uv Irradiation ◽  
Irradiation Effect

scholarly journals UV irradiation effect on the electrical properties of Pb2MoO5 single crystal

2018 ◽  
Vol 26 (2) ◽  
pp. 63-66
Author(s):  
I. P. Volnyanskaya ◽  
M. P. Trubitsyn ◽  
D. M. Volnianskii ◽  
D. S. Bondar
Keyword(s):  
Electrical Properties ◽  
Single Crystal ◽  
Uv Irradiation ◽  
Room Temperature ◽  
Uv Light ◽  
Dipole Moments ◽  
Irradiation Effect ◽  
Deep Traps ◽  
Temperature Dependences ◽  
Ac Field

Electrical properties of Pb2MoO5 single crystal were studied in AC field (f=1 kHz) after irradiation with UV light (290 K). It was found that UV irradiation caused appearance of maximums on permittivity ε and conductivity σ temperature dependences, which were observed around 530 K. The anomalies of ε and σ vanished after annealing at 700 K and could be restored by subsequent UV irradiation performed at room temperature. The magnitude of ε and σ peaks increased for higher exposition time. Above 600 K conductivity σ was practically independent on irradiation. It is proposed that photoelectrons induced by UV light, are trapped by Mo located -within the oxygen tetrahedrons with vacancy VO in one of the vertexes. The dipole moments of (MoO3) groups reorient at VO hopping through the tetrahedron vertexes. Annealing at 700 K thermally decomposes (MoO3)- complexes. For T>600 K behavior of σ(T) is determined by conduction currents and nearly insensitive to UV irradiation. At high temperatures the photoelectrons do not contribute to conductivity since they are bound in (MoO3)- centers, recombine with holes or re-captured by more deep traps.

UV irradiation effect on a new radiochromic gel

2015 ◽  
Vol 27 (7) ◽  
pp. 76002
Author(s):  
孙鹏 Sun Peng ◽  
胡娟 Hu Juan ◽  
傅玉川 Fu Yuchuan ◽  
李磊 Li Lei ◽  
王潇 Wang Xiao ◽  
...  
Keyword(s):  
Uv Irradiation ◽  
Irradiation Effect ◽  
Radiochromic Gel

Ultraviolet (UV) Irradiation Effect on Minority-Carrier Recombination Lifetime in Silicon Wafers with Oxide and Nitride Films

1993 ◽  
Vol 318 ◽  
Author(s):  
L. Zhong ◽  
F. Shimura
Keyword(s):  
Uv Irradiation ◽  
Minority Carrier ◽  
Correlation Energy ◽  
Surface Recombination ◽  
Chemical Vapor ◽  
Charge Trapping ◽  
Dielectric Films ◽  
Irradiation Effect ◽  
Recombination Lifetime ◽  
Carrier Recombination

ABSTRACTA new method based upon photoconductance measurement of the minority-carrier recombination lifetime is developed to investigate defects both in dielectric films and on the interface. In this method, surface recombination process in silicon substrate is used as a probe to detect the interface traps generated by ultraviolet (UV) irradiation as well as the defects in a film whose electronic state can be excited by UV irradiation. A variety of films, including native, chemical vapor deposited (CVD) and thermal oxide as well as CVD nitride, have been studied. In CVD nitride, for example, evidence is provided that K-centers, the main charge trapping defects, have a negative correlation energy (negative-U).

Adhesion and Barrier Properties Analysis of Silica-Like Thin Layer on Polyethylene Naphthalate Substrates for Thin Film Solar Cells

2010 ◽  
Vol 74 ◽  
pp. 113-118
Author(s):  
Maria Luisa Addonizio ◽  
Luigi Fusco
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Elastic Modulus ◽  
Uv Irradiation ◽  
Sol Gel ◽  
Polymer Surface ◽  
Barrier Properties ◽  
Irradiation Effect ◽  
Polyethylene Naphthalate ◽  
Water Contact

In this investigation the surface properties optimisation of a flexible PEN foil to use as substrate for thin film silicon solar cells is presented. The polymer surface, usually hydrophobic and inactive to chemical reactions, can give poor adhesion for films deposited on it. Furthermore, gas desorption from the polymer sometimes causes serious problems to the quality of the devices. To overcome these problems a thin film of silica-like functional material has been developed on polymer foil. Silica-like films were produced by sol-gel process starting from an organic silanes compound (APTMS) as precursor and the solution was deposited by spin-coating. Amorphous silica-like films were obtained with a hydrophilic surface. They were smooth, dense, homogeneous, transparent and exhibited an excellent adhesion to the polymer substrate due to the chemical bond between amine groups of the APTMS with carbonyl bonds in PEN. Physical properties such as elastic modulus and hardness and the UV irradiation effect on structure and surface hydrophilicity of the silica-like coatings have been analysed. A water contact angle of 34° was obtained after UV irradiation. Nanoindentation analysis showed that the silica-like coating have an hardness and an elastic modulus up to 2.0 GPa and 13.2 GPa respectively much higher than that of pure PEN. Oxygen permeability measured on silica-like coated PEN gave a value of 5.7 x 10-9 cc m/m2 s atm showing larger barrier properties respect to pure PEN. Strong adhesion, improved mechanical properties and barrier effect of our silica-like coating make the modified PEN substrate suitable to be used in thin film solar cell technology.

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