scholarly journals Life assessment of marine ethylene propylene rubber power cables based on hardness retention rate

2017 ◽  
Vol 66 (3) ◽  
pp. 475-484 ◽  
Author(s):  
Xiaokai Meng ◽  
Zhiqiang Wang ◽  
Guofeng Li
Keyword(s):  
Evaluation Method ◽  
Retention Rate ◽  
Condition Assessment ◽  
Life Assessment ◽  
Power Cables ◽  
Elongation At Break ◽  
Ethylene Propylene ◽  
Ethylene Propylene Rubber ◽  
Different Temperatures ◽  
Insulation Condition

AbstractThe lifetime of ethylene propylene rubber (EPR) insulated cables will decrease because of complex aging processes. From the safety perspective, insulation condition assessment of the cable is essential to maintain an efficient and reliable operation. As a nondestructive and online evaluation method, a hardness retention rate was used to estimate the lifetime of cable. First, accelerated thermal aging tests in the laboratory were performed to measure the elongation at break retention rate (EAB%) and a hardness retention rate at different temperatures. Second, the aging values were processed by the Arrhenius equation and time temperature superposition to assess aging lifetime of insulation at different temperatures and end levels. As the insulation condition assessment of the cable by hardness retention test has no approved standard, the EAB% data were correlated with hardness retention to provide an evaluation basis. The results show that when EAB% picks out the time corresponding to a certain amount of 50% degradation, 10% of hardness retention was chosen as the termination index.

Ethylene Propylene Rubber and Crosslinked Polyethylene as Insulations for 90°C Rated Medium Voltage Cables

1979 ◽  
Vol 52 (2) ◽  
pp. 410-424 ◽  
Author(s):  
R. B. Blodgett
Keyword(s):  
Fatigue Cracks ◽  
High Stress ◽  
Mechanical Damage ◽  
Power Cables ◽  
Reinforcing Effect ◽  
Ethylene Propylene ◽  
Medium Voltage ◽  
Electrical Stress ◽  
Primary Mechanism ◽  
Ethylene Propylene Rubber

Abstract Amorphous ethylene propylene rubber insulated power cables are expected to be more stable under high temperature conditions than crystalline crosslinked polyethylene insulated cables. The properties of amorphous EP rubbers are little affected by temperature from −30 to 150°C; those of crystalline XLPE fall off as temperature exceeds the melting point (around 100°C) of the crystalline regions. Probably reinforced amorphous EP rubber insulated cables are expected to be more stable in wet locations than unfilled XLPE insulated cables. They do not fail by the formation of water trees as the primary mechanism, since the bonds between filler and polymer are stronger than the forces responsible for water trees forming in XLPE cables in service. The reinforcing effect of fillers in EP rubber makes questionable any extrapolation from high stress treeing studies of unreinforced PE, XLPE, or EP polymers. For the longest possible life in wet locations insulation should be protected by a water impermeable metallic sheath, which must be protected against corrosion, mechanical damage, fatigue cracks, etc. Any insulation will eventually fail on continued exposure to water and electrical stress.

Influence of Vulcanizing System on the Properties of Rubbers Based on Ethylenepropylene Rubber

2021 ◽  
Vol 899 ◽  
pp. 239-244
Author(s):  
Larisa Yuryevna Zakirova
Keyword(s):  
Tensile Strength ◽  
High Temperatures ◽  
Organic Peroxide ◽  
Strength Properties ◽  
Maximum Speed ◽  
Elongation At Break ◽  
Ethylene Propylene ◽  
Rubber Compounds ◽  
Ethylene Propylene Rubber ◽  
Aging In Air

The article investigates the effect of vulcanizing systems of different activity on the vulcanization and elastic-strength properties of rubber compounds based on ethylene-propylene rubber Keltan . Were taken vulcanizing systems: a mixture of organic peroxide, sulfur and sulfenamide accelerator (1); a mixture of organic peroxide, sulfur and dithiodimorpholine (2); a mixture of organic peroxide, sulfur and thiuram accelerator (3); sulfur and sulfenamide accelerator (4). The vulcanization characteristics (maximum and minimum torques; times of onset, optimum and reaching the maximum speed of vulcanization) were evaluated. Elastic-strength (conditional tensile strength, elongation at break, hardness) properties of rubber compounds and operational (changes in conditional tensile strength, elongation at break after aging in air) were determined. It was found that the vulcanizing system (3) containing sulfur, peroxide in an amount of 7.0 parts by weight and thiuram accelerator imparts the best elastic and strength properties to rubber compounds and leads to their resistance to high temperatures.

Resistance to Thermal Oxidation of Ethylene Propylene Rubber and Polyhydroxybutyrate Blends

2017 ◽  
Vol 44 (5) ◽  
pp. 11-14 ◽  
Author(s):  
A.A. Ol'khov ◽  
L.S. Shibryaeva ◽  
Yu.V. Tertyshnaya ◽  
A.N. Kovaleva ◽  
E.L. Kucherenko ◽  
...  
Keyword(s):  
Thermal Oxidation ◽  
Testing Machine ◽  
Phase Interface ◽  
Tensile Testing Machine ◽  
Elongation At Break ◽  
Ethylene Propylene ◽  
Ethylene Propylene Rubber ◽  
Morphology Of Films ◽  
Kinetics Of ◽  
Structure Properties

The structure, properties, and kinetics of thermal oxidation of blends based on polyhydroxybutyrate (PHB) and ethylene propylene rubber (EPR) were studied. The physicomechanical properties were studied using a ZE-40 tensile testing machine (Germany), and the crystallisation temperature Tcr and melting temperature Tm of PHB in the blends were determined on a DSM-2M differential scanning calorimeter at a scanning rate of 16°C/min. The morphology of films was determined by scanning electron microscopy on a Hitachi S-570 microscope (Japan). The kinetics of thermal oxidation of the blends was assessed according to the amount of absorbed oxygen. With increase in the PHB content in the blend there is a reduction in the elongation at break and an increase in the tensile strength and modulus. Change in the PHB content and in the oxidation time leads to negligible changes in Tcr and Tm. It was established that the greatest reactivity of blends in relation to oxygen is observed in the range of PHB concentrations of 20–40%, where the greatest phase interface area is formed. It was shown that, by changing the ratios of EPR and PHB, it is possible to control the kinetics of thermal oxidation of the blends. It was shown that, in the range of concentrations of 50–70% PHB, phase inversion occurs in the blends.

Effect of Sulfur during Radiation Curing of Poly(Vinyl Ethyl Ether) and Ethylene-Propylene Rubber

1963 ◽  
Vol 36 (1) ◽  
pp. 248-258 ◽  
Author(s):  
Joginder Lal ◽  
James E. McGrath
Keyword(s):  
Tensile Strength ◽  
Ethyl Ether ◽  
Triphenyl Phosphine ◽  
Radiation Curing ◽  
Elongation At Break ◽  
Ethylene Propylene ◽  
Maximum Tensile Strength ◽  
Lower Radiation Dose ◽  
Ethylene Propylene Rubber ◽  
Sulfur Containing

Abstract A study was made of the effect of sulfur, during radiation curing, on the physical properties of poly(vinyl ethyl ether) and an ethylene/propylene copolymer containing HAF carbon black. The presence of sulfur enabled the attainment of higher maximum tensile strength and generally higher crosslink density than when sulfur was omitted. Furthermore, the maximum tensile strength of the sulfur-containing samples was obtained at a lower radiation dose than in the corresponding control experiments. For a given swelling ratio, a higher tensile strength was generally obtained for samples irradiated in the presence of sulfur. For a given dose of radiation, the per cent elongation-at-break values of poly(vinyl ethyl ether) samples decreased as the amount of sulfur in the recipe was increased. In contrast, in the ethylene/propylene rubber the presence of sulfur resulted in an increase in the elongation values. The per cent sol values were also quite high for the ethylene/propylene vulcanizates as compared to the corresponding values in poly(vinyl ethyl ether) samples. In both rubbers, lower sol values were obtained in the presence of sulfur. Chemically bound sulfur was found in poly(vinyl ethyl ether) samples irradiated in the presence of elemental sulfur or dicyclopentamethylene thiuram tetrasulfide. The ability of the network to lose a portion of the combined sulfur by reaction with triphenyl phosphine may indicate that some of the crosslinks contain disulfide and/or polysulfide groups.

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