scholarly journals THE INVESTIGATION ON THERMAL OXIDATIVE DESTRUCTION AND ASSESSMENT OF RUBBER SERVICE PERIOD BASED ON TRIPLE COPOLYMER OF TETRAFLUOROETHYLENE, VINYLIDENE FLUORIDE AND HEXAFLUOROPROPYLENE

Author(s):  
I. M. Baev ◽  
T. V. Sclyarova ◽  
S. V. Borisov ◽  
I. M. Gres ◽  
M. A. Vaniev

By thermogravimetric analysis it was studied the thermal oxidative degradation of rubber based on a triple copolymer of tetrafluoroethylene, vinylidene fluoride, and hexafluoropropylene. It was found that the object is characterized by a sufficiently high heat resistance, which is proven by the rather high temperature of loss of 5% of the initial mass of the sample (412 ° C). The service life of the tested unloaded material in air atmosphere, according to the Arrhenius equation, is 2084, 450 and 107 days at the temperature of 185, 200 and 215 ° C respectively.

2015 ◽  
Vol 1088 ◽  
pp. 343-347
Author(s):  
Peng Wei ◽  
Shuo Han Huang ◽  
Yan Ping Wang ◽  
Yi Min Wang

In this study, the thermal oxidative degradation behavior of thermotropic liquid crystal copolyesters P-BPAFx containing 2.5-10 mol% bisphenol AF unit were evaluated by thermogravimetric analysis (TGA) technique under air atmosphere and the degradation activation energy (E) was obtained from Kissinger and Kissinger-Akahira-Sunose (KAS) method. The degradation behavior of copolyester are strongly dependent on the molar percentage of BPAF unit. Results showed that the E values obtained by the two methods increase first and then decrease slightly with increasing the BPAF unit and follow the order P-BPAF5.0< P-BPAF10<P-BPAF2.5, indicating P-BPAF2.5 has good thermal stability. The reason for this phenomenon was discussed in detail in the text.


2021 ◽  
Vol 410 ◽  
pp. 587-592
Author(s):  
Gulgena D. Shakirova ◽  
Natalya V. Romanova ◽  
Lenar N. Shafigullin

The paper provides the results of the studies on the influence of high temperatures and aggressive media on the performance properties of O-rings having one name but made by different manufacturers. O-rings by supplier No. 1 are made from fluorosilicone rubber, and O-rings by supplier No. 2 are made from fluororubber. The analysis of O-rings showed that the color of O-rings made from fluorosilicone rubber changed and their physical mechanical properties decreased after operation when subjected to G-energy Si-OAT and G-energy SNF coolants. The comparative analysis of TGA curves of O-rings showed that O-rings made from fluororubber were more heat stable than O-rings made from fluorosilicone rubber, i.e. they can withstand higher operating temperatures in an air atmosphere. Fluoroelastomers can recover quickly and are used to manufacture products which should have a high heat resistance during operation and high resistance to aggressive coolants.


Alloy Digest ◽  
1967 ◽  
Vol 16 (4) ◽  

Abstract PRESSURDIE-1 is an air-hardening hot work tool and die steel having high heat resistance and good high temperature strength properties. It is recommended for die casting dies, extrusion and forging dies. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: TS-191. Producer or source: Continental Copper & Steel Industries Inc..


Alloy Digest ◽  
1963 ◽  
Vol 12 (11) ◽  

Abstract PEERLESS LCT2 is a hot work steel which possesses high heat resistance and a high degree of working hardness at elevated temperatures. This steel is best applied where hardness and resistance to abrasion are of more importance than toughness. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness. It also includes information on high temperature performance as well as forming, heat treating, and machining. Filing Code: TS-140. Producer or source: Crucible Steel Company of America.


FirePhysChem ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 8-20
Author(s):  
Xingyu Huo ◽  
Fanfan Wang ◽  
Liang Liang Niu ◽  
Ruijun Gou ◽  
Chaoyang Zhang

2021 ◽  
Vol 9 (3) ◽  
pp. 667
Author(s):  
Zhiwei Tu ◽  
Peter Setlow ◽  
Stanley Brul ◽  
Gertjan Kramer

Bacterial endospores (spores) are among the most resistant living forms on earth. Spores of Bacillus subtilis A163 show extremely high resistance to wet heat compared to spores of laboratory strains. In this study, we found that spores of B. subtilis A163 were indeed very wet heat resistant and released dipicolinic acid (DPA) very slowly during heat treatment. We also determined the proteome of vegetative cells and spores of B. subtilis A163 and the differences in these proteomes from those of the laboratory strain PY79, spores of which are much less heat resistant. This proteomic characterization identified 2011 proteins in spores and 1901 proteins in vegetative cells of B. subtilis A163. Surprisingly, spore morphogenic protein SpoVM had no homologs in B. subtilis A163. Comparing protein expression between these two strains uncovered 108 proteins that were differentially present in spores and 93 proteins differentially present in cells. In addition, five of the seven proteins on an operon in strain A163, which is thought to be primarily responsible for this strain’s spores high heat resistance, were also identified. These findings reveal proteomic differences of the two strains exhibiting different resistance to heat and form a basis for further mechanistic analysis of the high heat resistance of B. subtilis A163 spores.


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