Research on Thermal Aging Characteristics and Mechanism of the Silicon Rubber Insulation Layer of Cable Joints

2019 ◽  
Vol 960 ◽  
pp. 161-166 ◽  
Author(s):  
Yong Lan Li ◽  
Man Shi Qiu ◽  
Jia Wei Ma ◽  
Guo Wen Kuang ◽  
Nai Kui Gao ◽  
...  
Keyword(s):  
Mass Loss ◽  
Silicone Rubber ◽  
Thermal Aging ◽  
Mass Loss Rate ◽  
Chain Structure ◽  
Decomposition Temperature ◽  
Insulation Layer ◽  
Initial Decomposition Temperature ◽  
Theoretical Support ◽  
Degradation Reaction

In order to solve the thermal aging problem of silicone rubber insulation layer of 220 kV integral prefabricated cable joints, the mass loss and thermal gravimetric (TG) were tested. The thermal aging mechanism of thermal degradation reaction of silicone rubber molecular chains was analyzed by gel content test and infrared spectrum test (IR). The results showed that the cross-linked network of the molecular chain structure gradually deteriorates, resulting in the increase of mass loss rate and the decrease of thermal stability. The results also showed that the increase of dual peak of differential thermal weight (DTG), the decrease of initial decomposition temperature and the remaining mass. With increasing aging temperature and aging time, the aging would be accelerated. These properties could reflect the degree of thermal aging of silicone rubber insulation layer. The results could also provide theoretical support for the preparation, operation and maintenance for silicone rubber cable joints.

scholarly journals Selective Production of Acetic Acid via Catalytic Fast Pyrolysis of Hexoses over Potassium Salts

Catalysts ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 502
Author(s):  
Wenyue Kang ◽  
Zhijun Zhang
Keyword(s):  
Acetic Acid ◽  
Mass Loss Rate ◽  
Maximum Yield ◽  
Potassium Acetate ◽  
Decomposition Temperature ◽  
Initial Decomposition Temperature ◽  
Chemical Catalysis ◽  
On Line ◽  
Maximum Mass Loss

Glucose and fructose are widely available and renewable resources. They were used to prepare acetic acid (AA) under the catalysis of potassium acetate (KAc) by thermogravimetric analysis (TGA) and pyrolysis coupled with gas chromatography and mass spectrometry (Py-GC/MS). The TGA result showed that the KAc addition lowered the glucose’s thermal decomposition temperatures (about 30 °C for initial decomposition temperature and 40 °C for maximum mass loss rate temperature), implying its promotion of glucose’s decomposition. The Py-GC/MS tests illustrated that the KAc addition significantly altered the composition and distribution of hexose pyrolysis products. The maximum yield of AA was 52.1% for the in situ catalytic pyrolysis of glucose/KAc (1:0.25 wt/wt) mixtures at 350 °C for 30 s. Under the same conditions, the AA yield obtained from fructose was 48% and it increased with the increasing amount of KAc. When the ratio reached to 1:1, the yield was 53.6%. In comparison, a study of in situ and on-line catalytic methods showed that KAc can not only catalyze the primary cracking of glucose, but also catalyze the cracking of a secondary pyrolysis stream. KAc plays roles in both physical heat transfer and chemical catalysis.

scholarly journals The Use of Thermal Techniques in the Characterization of Bio-Sourced Polymers

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1686
Author(s):  
Ignazio Blanco ◽  
Valentina Siracusa
Keyword(s):  
Thermal Analysis ◽  
Mass Loss Rate ◽  
Mechanical Analysis ◽  
Decomposition Temperature ◽  
Scanning Calorimetry ◽  
Initial Decomposition Temperature ◽  
Research Areas ◽  
Tan Δ ◽  
Thermal Techniques ◽  
The Right

The public pressure about the problems derived from the environmental issues increasingly pushes the research areas, of both industrial and academic sectors, to design material architectures with more and more foundations and reinforcements derived from renewable sources. In these efforts, researchers make extensive and profound use of thermal analysis. Among the different techniques available, thermal analysis offers, in addition to high accuracy in the measurement, smartness of execution, allowing to obtain with a very limited quantity of material precious information regarding the property–structure correlation, essential not only in the production process, but overall, in the design one. Thus, techniques such as differential scanning calorimetry (DSC), differential thermal analysis (DTA), dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) were, are, and will be used in this transition from fossil feedstock to renewable ones, and in the development on new manufacturing processes such as those of additive manufacturing (AM). In this review, we report the state of the art of the last two years, as regards the use of thermal techniques in biopolymer design, polymer recycling, and the preparation of recyclable polymers as well as potential tools for biopolymer design in AM. For each study, we highlight how the most known thermal parameters, namely glass transition temperature (Tg), melting temperature (Tf), crystallization temperature (Tc) and percentage (%c), initial decomposition temperature (Ti), temperature at maximum mass loss rate (Tm), and tan δ, helped the researchers in understanding the characteristics of the investigated materials and the right way to the best design and preparation.

scholarly journals Effects of Zirconium Silicide on the Vulcanization, Mechanical and Ablation Resistance Properties of Ceramifiable Silicone Rubber Composites

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 496 ◽  
Author(s):  
Jiuqiang Song ◽  
Zhixiong Huang ◽  
Yan Qin ◽  
Honghua Wang ◽  
Minxian Shi
Keyword(s):  
Thermal Conductivity ◽  
Silicone Rubber ◽  
Thermal Protection ◽  
Permanent Deformation ◽  
Ablation Rate ◽  
Decomposition Temperature ◽  
Rubber Composites ◽  
Initial Decomposition Temperature ◽  
Ablation Resistance ◽  
Zirconium Silicide

Ceramifiable silicone rubber composites play important roles in the field of thermal protection systems (TPS) for rocket motor cases due to their advantages. Ceramifiable silicone rubber composites filled with different contents of ZrSi2 were prepared in this paper. The fffects of ZrSi2 on the vulcanization, mechanical and ablation resistance properties of the composites were also investigated. The results showed that the introduction of ZrSi2 decreased the vulcanization time of silicone rubber. FTIR spectra showed that ZrSi2 did not participate in reactions of the functional groups of silicone rubber. With the increasing content of ZrSi2, the tensile strength increased first and then decreased. The elongation at break decreased and the permanent deformation increased gradually. The thermal conductivity of the composite increased from 0.553 W/(m·K) to 0.694 W/(m·K) as the content of the ZrSi2 increased from 0 to 40 phr. In addition, the thermal conductivity of the composite decreased with the increase of temperature. Moreover, thermal analysis showed that the addition of ZrSi2 increased the initial decomposition temperature of the composite, but had little effect on the peak decomposition temperature in nitrogen. However, the thermal decomposition temperature of the composite in air was lower than that in nitrogen. The addition of ZrSi2 decreased the linear and mass ablation rate, which improved the ablative resistance of the composite. With the ZrSi2 content of 30 phr, the linear and mass ablation rate were 0.041 mm/s and 0.029 g/s, decreasing by 57.5% and 46.3% compared with the composite without ZrSi2, respectively. Consequently, the ceramifiable silicone rubber composite filled with ZrSi2 is very promising for TPS.

Study on the Thermal Stability of MUF Co-Polymerization Resin

2010 ◽  
Vol 146-147 ◽  
pp. 1038-1042
Author(s):  
Yun Wu Zheng ◽  
Li Bin Zhu ◽  
Ji You Gu ◽  
Yan Hua Zhang
Keyword(s):  
Mass Loss ◽  
Formaldehyde Emission ◽  
Decomposition Temperature ◽  
Productive Efficiency ◽  
Experimental Result ◽  
Initial Decomposition Temperature ◽  
Production Practice ◽  
Higher Temperature ◽  
Degree Of Curing ◽  
Poly Condensation

Curing is the key to the bonding, the study indicate that: curing effect on the glue bond strength, formaldehyde emission as well as Productive Efficiency; the better curing system can ensure the Productive Efficiency in basic to decrease the FE. This paper considered the production practice, studied the curing properties of different MUF resin with TGA. The experimental result: Different curing systems, made different curing process. For A curing system, curing rate is the fastest, the degree of curing is best. Cured stability is well. While in the C curing system, Because of their poor degree of cross-linking, poly-condensation cross-linked imperfect. While, Along with the increasing of n(F):n(U1), initial decomposition temperature increased, the maximum rate of mass loss moved to higher temperature, mass loss declined, decomposition activation energy increases, aging resistance increased.

Electrical insulation properties of silicone rubber under accelerated corona and thermal aging

2020 ◽  
Author(s):  
El Hadi Belhiteche ◽  
Sébastien Rondot ◽  
Mustapha Moudoud ◽  
Philippe Dony ◽  
Omar Jbara
Keyword(s):  
Silicone Rubber ◽  
Thermal Aging ◽  
Electrical Insulation ◽  
Electrical Insulation Properties

scholarly journals Asteroseismology of luminous red giants with Kepler. II. Dependence of mass loss on pulsations and radiation

2020 ◽  
Author(s):  
Jie Yu ◽  
Saskia Hekker ◽  
Timothy R Bedding ◽  
Dennis Stello ◽  
Daniel Huber ◽  
...  
Keyword(s):  
Mass Loss ◽  
Mass Loss Rate ◽  
Asymptotic Giant Branch ◽  
Red Giants ◽  
Asymptotic Giant Branch Stars ◽  
Chemical Enrichment ◽  
Dust Mass ◽  
Red Giant ◽  
The Masses ◽  
Loss Rates

Abstract Mass loss by red giants is an important process to understand the final stages of stellar evolution and the chemical enrichment of the interstellar medium. Mass-loss rates are thought to be controlled by pulsation-enhanced dust-driven outflows. Here we investigate the relationships between mass loss, pulsations, and radiation, using 3213 luminous Kepler red giants and 135000 ASAS–SN semiregulars and Miras. Mass-loss rates are traced by infrared colours using 2MASS and WISE and by observed-to-model WISE fluxes, and are also estimated using dust mass-loss rates from literature assuming a typical gas-to-dust mass ratio of 400. To specify the pulsations, we extract the period and height of the highest peak in the power spectrum of oscillation. Absolute magnitudes are obtained from the 2MASS Ks band and the Gaia DR2 parallaxes. Our results follow. (i) Substantial mass loss sets in at pulsation periods above ∼60 and ∼100 days, corresponding to Asymptotic-Giant-Branch stars at the base of the period-luminosity sequences C′ and C. (ii) The mass-loss rate starts to rapidly increase in semiregulars for which the luminosity is just above the red-giant-branch tip and gradually plateaus to a level similar to that of Miras. (iii) The mass-loss rates in Miras do not depend on luminosity, consistent with pulsation-enhanced dust-driven winds. (iv) The accumulated mass loss on the Red Giant Branch consistent with asteroseismic predictions reduces the masses of red-clump stars by 6.3%, less than the typical uncertainty on their asteroseismic masses. Thus mass loss is currently not a limitation of stellar age estimates for galactic archaeology studies.

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