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Kuzina, S. I.; Pivovarov, A. P.; Kiryukhin, D. P.; Mozhaev, P. S.; Михайлов, А. И.; Barkalov, I.M.

doi:10.1023/a:1013692226721

Cited by 4 publications

(4 citation statements)

References 3 publications

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“…When solid HCN undergoes radiolysis (with doses of 1 ± 800 kGy) at 77 K, the active sites of radical and radical ion nature are stabilised in the crystal. 54 On subsequent heating of the system, a brown polymer (7HC=N7) n , which contains conjugated double bonds, and crystals of the tetramer (1,2-diaminomaleonitrile) are formed in the solid phase. At low temperatures, the polymerisation rates of crystalline HCN are low, and chain polymerisation at 77 K under g-radiation is not observed.…”

Section: Low-temperature Radiation-induced Conversions Of Hydrogen Cy...mentioning

confidence: 99%

“…The ESR spectrum of the polymer represents a singlet typical of polyconjugated systems. Within the framework of the suggested radical transformation scheme, 54 the brown colour of the polymer may be explained by the formation of the 7HC=N7HC=N7 conjugation chain. The formation of needle-like crystals of 1,2-diaminomaleonitrile (tetramer of hydrogen cyanide) may be 53 due to the formation of an intermediate biradical, viz., aminocyanocarbene; dimerisation of the latter results in the tetramer.…”

Section: Low-temperature Radiation-induced Conversions Of Hydrogen Cy...mentioning

confidence: 99%

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Chain chemical reactions at low temperatures

Kiryukhin¹,

Barkalov²

2003

Russ. Chem. Rev.

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The review generalises results of studies on chain The review generalises results of studies on chain cryochemical polymerisation and copolymerisation, oxidation, cryochemical polymerisation and copolymerisation, oxidation, chlorination and hydrobromination of saturated hydrocarbons chlorination and hydrobromination of saturated hydrocarbons and alkenes in the crystalline and glassy state. Chain chemical and alkenes in the crystalline and glassy state. Chain chemical reactions that occur at liquid helium temperature with a meas-reactions that occur at liquid helium temperature with a measurable, temperature-independent rate are considered; high-inten-urable, temperature-independent rate are considered; high-intensity autowave modes of low-temperature reactions in solid phase sity autowave modes of low-temperature reactions in solid phase are discussed. The bibliography includes 111 references are discussed. The bibliography includes 111 references. .

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Section: Low-temperature Radiation-induced Conversions Of Hydrogen Cy...mentioning

confidence: 99%

Section: Low-temperature Radiation-induced Conversions Of Hydrogen Cy...mentioning

confidence: 99%

Chain chemical reactions at low temperatures

Kiryukhin¹,

Barkalov²

2003

Russ. Chem. Rev.

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“…At 77 K the radiolytic yield of paramagnetic centres is 6/100 eV. 514 For both LDPE and HDPE, higher irradiation temperature leads to an increase of crosslinking ef¢ciency and gas yield, and thermodegradation resulting in chain scission becomes important above 300 C. 515 Temperature dependences on the radiation-induced phenomena of PTFE have been studied (77^653 K). Chain scission increases with increasing irradiation temperature, with G-value reaching 20, but is drastically reduced in the molten state at 613 K. Above 633 K radiation-induced crosslinking mainly occurs; however, parallel thermal depolymerization or decomposition takes place to some extent.…”

Section: Properties and Degradationmentioning

confidence: 99%

7 Radiation chemistry

Belloni

Delcourt

Houée-Levin⊥

et al. 2000

Annu. Rep. Prog. Chem., Sect. C

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We try in this review to survey advances in all the aspects of Radiation Chemistry (the effects of high energy or ionizing radiation), both basic and applied, made during the period 1995^1999, after the last report issued at the end of 1994. 1 Classically, two main classes of studies are relevant. The ¢rst one includes the primary phenomena induced by the interaction of high-energy radiation with a chemical system. The way the energy is spatially deposited is indeed highly nonhomogeneous and depends on the type of radiation considered. Mutual reactions between the primary species produced also depend on their initial spatial distribution, and therefore on the energy absorption pattern. The kinetic aspects derive directly from the initial events following radiation absorption and thus, when observed at times as short as possible, give useful information on the early energy distribution for each of the radiation types, X-and g-photons, electrons and heavy particles, and, on the in£uence of their intensity and energy per particle.The second class of studies utilizes the background knowledge of radiation chemistry to generate and then to observe the fate of chemical transient species known to be involved in very important chemical or biochemical processes. Numerous data, such as the nature of reaction products, the absolute rate constants, the sequence of elementary reactions constituting a mechanism, and the thermodynamic and spectroscopic properties of short-lived species have been attained. This kind of study of transients and reaction mechanisms, which can be approached only by pulse techniques (essentially pulse radiolysis or laser photolysis, each with its speci¢c advantages), constitutes the new ¢eld of fast to ultrafast chemistry. It concerns extended domains of physical, organic, inorganic, and bio-chemistry. Moreover, the understanding of mechanisms is quite helpful in suggesting new ways of synthesis or degradation induced by irradiation and is now extensively used in developing various speci¢c processes in applied chemistry. The number of studies on the chemical mechanisms and in applied radiation chemistry constitutes an increased fraction of the total publications in radiation chemistry, which we estimate to be around 4000 over the period considered (almost constant compared to the preceding 5-year

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“…It is well-known that ESR spectroscopy is the only technique established to detect radicals from different sources [11][12][13]. Also, it has been widely used in polymers degradation analysis [14,15]. However, it has been never used for thermal endurance characterization of manufactured and raw insulating materials used by cable industries yet.…”

Section: Introductionmentioning

confidence: 99%

Electron spin resonance spectral study of PVC and XLPE insulation materials and their life time analysis

Morsy

Shwehdi

2006

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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Electron spin resonance (ESR) study is carried out to characterize thermal endurance of insulating materials used in power cable industry. The presented work provides ESR investigation and evaluation of widely used cable insulation materials, namely polyvinyl chloride (PVC) and cross-linked polyethylene (XLPE). The results confirm the fact that PVC is rapidly degrades than XLPE. The study also indicates that colorants and cable's manufacturing processes enhance the thermal resistance of the PVC. It also verifies the powerfulness and the importance of the ESR-testing of insulation materials compared to other tests assumed by International Electrotechnical Commission (IEC) Standard 216-procedure, e.g. weight loss (WL), electric strength (ES) or tensile strength (TS). The estimated thermal endurance parameters by ESR-method show that the other standard methods overestimate these parameters and produce less accurate thermal life time curves of cable insulation materials.

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Cited by 4 publications

References 3 publications

Chain chemical reactions at low temperatures

Chain chemical reactions at low temperatures

7 Radiation chemistry

Electron spin resonance spectral study of PVC and XLPE insulation materials and their life time analysis

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