Wyniki wyszukiwania - Biblioteka Nauki

1

The grain size influence on the E1'centre observed in quartz of atmospheric deposition at two Japanese cities : a preliminary study

100%

Yamamoto Y. , Toyoda S. , Nagasima K. , Igarashi Y. , Tada R.

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2010

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tom Vol. 37

9-12

EN

The grain size influence on the number of oxygen vacancies in quartz was investigated by ESR in atmospheric deposition collected at two Japanese cities, Fukuoka and Akita, in 1969 and 1971. The finer grain size fraction shows the highest value of concentration of oxygen vacancies, most closely resembling dust originating in the Taklamakan desert. Month to month and year to year variation of the dependence was also observed which could possibly be attributed to the variation of the mixture ratio of at least two dust sources in China, A conclusive statement can not be made at this stage.

2

Static and dynamic structural distortion of cyclohexane radical cations in low temperature matrices: an ESR study

100%

Shiotani M. , Wang P. , Komaguchi K.

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1999

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tom Vol. 47, No.1

89-102

3

Radiation-induced oxidation of thiaproline derivatives in frozen acidic aqueous solutions: theoretical and Electron Spin Resonance study

100%

Pogocki D. , Sadło J.

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2000

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tom Vol. 45, nr 1

101-108

EN

Radicals formed by gamma-radiolysis of thiaproline (thiazolidine-4-carboxylic acid) amino acid and its derivatives in a frozen acidic aqueous solution at 77 K and by subsequent warming from 95 to 200 K have been studied by electron spin resonance (ESR). The experimental parameters of radical spectra were compared with those obtained by quantum-mechanical calculations on AM1 and PM3 semiempirical levels.

4

Electron Spin Resonance study of radiation-induced radicals in polycrystalline oligopeptides containing methionine

100%

Strzelczak G. , Bobrowski K. , Kozubek H. , Michalik J.

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2000

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tom Vol. 45, nr 1

93-100

EN

The radicals formed on g-radiolysis of oligopeptides containing methionine and glycine residues in the polycrystalline state at 77 K and on subsequent warming over the temperature range of 77-293 K were identified using the electron spin resonance (ESR) technique. In all oligopeptides studied, anion peptide radicals and monomeric sulfur radical cations over the temperature range of 77-95 K and decarboxylation and deamination radicals over the temperature range of 180-250 K were detected. In addition, in oligopeptides containing adjacent methionyl residues, three-electron-bonded dimeric sulfur radical cations (S\S)+ were detected at 110 K. In oligopeptides containing N-terminal methionine residue, H-abstraction radicals in the side chain of methionine residue were observed over the temperature range of 180-250 K. H-abstraction radicals at the a-carbon of the C-terminal amino acid residue were detected at 293 K in most of oligopeptides studied, in contrast to Met-Gly-Met and Met-Gly-Met-Met peptides were H-abstraction radicals at the alfa-carbon of the internal glycine residue were obserwed.

5

Analiza porównawcza wyników oznaczeń laboratoryjnych biomarkerów zapalenia – wskaźnika sedymentacji krwinek czerwonych (ESR) i białka C-reaktywnego (CRP) w stanach zapalnych u pacjentów hospitalizowanych

100%

Siudzińska A. , Łobos M. , Sujecki A. , Paradowski M. , Łobos M.

Folia Medica Lodziensia

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2013

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tom 40

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nr 2

207-233

EN

Introduction: Erythrocyte sedimentation rate (ESR, in Poland known as OB) and C-reactive protein (CRP) are biomarkers most often used to diagnose and monitor systemic inflammation. However, they are independent markers and have different properties. The aim of this study was to compare the values of specific markers of systemic inflammation such as ESR and CRP in patients hospitalized in the internal wards and suspected of suffering from systemic inflammation. Material and methods: The study group included 187 patients (99 women and 88 men, aged from 20 to 97 years) hospitalized in the internal medicine clinics of the Military Medical Academy University Teaching Hospital - Central Veterans' Hospital in Lodz. Each marker of inflammation, ESR and CRP, were measured in patients’ peripheral blood (ESR) and serum (CRP). Results: For the diagnosis of inflammation there was no significant correlation between CRP and ESR in groups of patients both with mild (CRP > 6.1 – 40 mg/L) and severe (CRP ≥ 40.1) inflammation. However, in persons with highly developed inflammation (ESR ≥ 31 mm/h and CRP ≥ 40.1 mg/L) there was a strong correlation between the mentioned biomarkers (r = 0.9973). Conclusions: The results indicate that CRP and ESR biomarkers are independent parameters that are clinically useful for the diagnosis and monitoring of inflammations. For the diagnosis of acute inflammation the designation of serum CRP is clinically more useful than the measurement of ESR.

PL

Wstęp: Odczyn opadania krwinek czerwonych (ESR, w Polsce znany pod nazwą odczyn Biernackiego - OB) i stężenie białka C-reaktywnego (CRP) są najczęściej wykorzystywanymi przez lekarzy biomarkerami do rozpoznawania i monitorowania stanu zapalnego ustroju. Jednak są one wskaźnikami niezależnymi i cechują się różnymi własnościami. Celem niniejszej pracy była analiza porównawcza wyników oznaczeń dwóch laboratoryjnych biomarkerów zapalenia: ESR i CRP u pacjentów leczonych na oddziałach internistycznych, u których podejrzewano narastający lub istniejący proces zapalny. Materiał i metody: Badaniem objęto 187 chorych (99 kobiet i 88 mężczyzn, w wieku od 20 do 97 lat) hospitalizowanych w klinikach chorób wewnętrznych Uniwersyteckiego Szpitala Klinicznego im. Wojskowej Akademii Medycznej – Centralnego Szpitala Weteranów w Łodzi. U każdego pacjenta w tym samym czasie wykonano oznaczenie dwóch wskaźników stanu zapalnego: ESR i CRP. Wyniki: Dla rozpoznawania narastającego zapalenia nie wykazano istotnej korelacji między CRP i ESR w grupach pacjentów zarówno o małym (CRP > 6,1 – 40 mg/L), jak i dużym (CRP ≥ 40,1) nasileniu zapalenia. Z drugiej strony, u ludzi z silnie już rozwiniętym zapaleniem (ESR ≥ 31 mm/h i CRP ≥ 40,1 mg/L) zaznaczyła się wysoka korelacja pomiędzy tymi biomarkerami (r = 0,9973). Wnioski: Wyniki wskazują, że analizowane biomarkery CRP i ESR są parametrami niezależnymi i są klinicznie użyteczne w rozpoznawaniu i obserwacji stanów zapalnych. W rozpoznawaniu zapalenia o ostrym przebiegu bardziej użytecznym klinicznie biomarkerem jest stężenie CRP w surowicy niż wartość ESR.

6

Analysis of experimental results obtained by ESR and VAR process for special steels

89%

Zaman F. , Iorga G. , Ionescu M. , Petrescu A. , Carciumareasa D.

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2008

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tom Vol. 53, iss. 2

629-632

EN

The paper presents the results regarding quality of special steels for aero industry, obtained by two different processes: Electro Slag Remelting (ESR) and Vacuum Arc Remelting (VAR) on pilot experiments. The main object of these trials was obtaining super clean steels (oxygen <20 ppm, hydrogen <1 ppm, nitrogen <20 ppm, sulphur <50 ppm, phosphorus <100 ppm) and a controlled solidificated structure of steel semis. The experiments took off the benefits of vacuum arc remelting process, for decreasing gaseous content of steels versus electro slag remelting process which can improve the decreasing of sulphur content of steel. In order to analyse the influence of a double vacuum process VIM – VAR (Vacuum Induction Melting and Vacuum Arc Remelting) on quality of steel, some trials were also performed.

PL

Artykuł przedstawia wyniki dotyczące jakości stali specjalnych stosowanych w przemyśle lotniczym, uzyskane z dwóch różnych procesów: elektrożużlowego przetapiania stali i przetapiania w próżni na podstawie badań pilotażowych. Głównym przedmiotem badań było uzyskanie super czystych stali (tlen <20 ppm, wodór <1 ppm, azot <20 ppm, siarka <50 ppm, fosfor <100 ppm) i kontrola struktury bliźniaków w krzepnącej stali. W doświadczeniach wykorzystano korzyści płynące z odgazowania stali w procesie próżniowym, naprzeciw możliwościom elektrożużlowego przetapiania, które poprawia odsiarczanie stali. Wykonane zostało również kilka prób, aby przeanalizować wpływ procesu VIM – VAR na jakość stali.

7

Optical studies of undoped GaP grown by LEC method

89%

Surma B. , Wnuk A. , Piersa M. , Strzelecka S. , Pawłowski M. , Jurkiewicz-Wegner E.

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2009

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tom T. 37, nr 2

38-46

EN

The features of undoped LEC GaP crystals with particular emphasis on their luminescence properties are presented. Hall and GDMS measurements revealed that C and Si are the main residual shallow impurities. Semi-insulating features of the samples were controlled by the presence of the phosphorous anti-site defect, P4PGa. Its presence was confirmed by ESR measurements as well as the emission at 1.05 eV. For p-type samples with phosphorous antisite defect, P4PGa, and high carbon concentration an emission at 1.9 eV has been observed. We tentatively assign this emission to the recombination of the excitons bound with isoelectronic complex PGaCp. A deep-centre luminescence with the maximum at 1.33 eV was dominant in n-type GaP and in electron-irradiated samples. The obtained results indicate that this emission results from native defect complex.

PL

W pracy przedstawione są badania niedomieszkowanych kryształów GaP otrzymywanych w ITME metodą LEC ze szczególnym uwzględnieniem ich własności luminescencyjnych. Pomiary Halla, absorpcyjne i GDMS wykazały, że głównymi płytkimi domieszkami resztkowymi w otrzymywanych kryształach są węgiel i krzem. Półizolujące własności badanych kryształów determinowane były obecnością fosforowego antystrukturalnego defektu P4PGa. Obecność jego została potwierdzona poprzez obecność linii rezonansowej w widmie ESR, jak również poprzez obecność emisji w podczerwieni z maksimum przy l .05 eV. W kryształach typu p, w których potwierdzona została obecność defektu P4PGa oraz stwierdzono relatywnie wysoką koncentrację węgla w widmie luminescencyjnym pojawiło się pasmo luminescencyjne z maksimum przy l .9 eV. Nasza sugestia odnośnie pochodzenia tej emisji wiązana jest z wytworzeniem się isoelektronowego kompleksu PGaCp. W niedomieszkowanych próbkach typu w jak również w próbce naświetlanej elektronami luminescencja pochodząca od głębokich centrów zdominowana była obecnością pasma leżącego przy 1.33 eV. Przeprowadzone badania wykazały, że jest ona związana z obecnością kompleksu wytworzonego przez macierzyste atomy sieci, natomiast nie zależy od koncentracji domieszek resztkowych.

8

ESR dating of marine barite in chimneys deposited from hydrothermal vents

88%

Okumura T. , Toyoda S. , Sato F. , Uchida A. , Ishibashi J. , Nakai S.

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2010

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tom Vol. 37

57-61

EN

Electron Spin Resonance (ESR) dating of marine barite in chimneys deposited from hydrothermal vents was attempted to determine the time since hydrothermal activity occurred. In this study, we used Barite (BaSO4) precipitated in icroenvironments in the chimneys deposited from the hydrothermal vents at the Archaean site in South Mariana spreading centre (12°56.4'N, 143°37.9'E) and at Hakurei site in the Izena caldron (27°15‘N, 127°04‘E) for ESR measurements. ESR spectrum of marine barite is characterized by an electron-type centre with g values of 2.0034, 2.0022 and 1.9995 attributed to SO3 –. The signal intensity increased with gamma ray dose. The dose rates of hydrothermal chimneys from the Archaean site and from the Hakurei site were calculated using a model that assumed a grain size and that incorporation of radionuclides after 226Ra in U series into the chimney, and assuming the efficiency of the defect formation by alpha particles to be the same as that for OSL. The ESR ages were estimated to be 470 years old for barite from the Archaean site and 5670 years old for one from the Hakurei site, although there is a considerable difference between the present ESR ages and the 210Pb/226Ra disequilibrium ages previously reported.

9

A dimeric copper coumarin complex: synthesis and crystal structure of [{Cu(4-methyl-7-(salicylideneamino)coumarin)2}2]

88%

Aazam E. , EL Husseiny A. , Hitchcock P. , Alshehri J.

Open Chemistry

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2008

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tom 6

|

nr 2

319-323

EN

A binuclear copper complex [{Cu(L)2}2], C68H48Cu2N4O12C (where L is 4-methyl-7-(salicylideneamino)coumarin), has been synthesized and characterized using elemental analysis, molar conductance measurements, and infrared, ultraviolet and ESR spectrosopy. The molecular structure of title compound, determined by single-crystal X-ray diffraction studies, reveals that the two symmetric Cu(L)2 units are associated into a dimer by rather long Cu...O bonds. The Cu(II) ions are bridged via the phenolic oxygen of one of the monomers and have distorted trigonal bipyramidal conformation geometry. Within each monomer the two methylsubstituted coumarin skeletons are trans to one another, but adopt a parallel arrangement with respect to the other monomer. Only half of the complex molecule can be found in the asymmetric unit, Z′ = 0.5, the other half is generated by the symmetry centre. [...]

10

Hydrazinium Complexes of Lanthanide and Transition Metal Squarates

88%

Vairam S. , Govindarajan S.

|

2006

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tom Vol. 80, nr 10

1601-1614

EN

Reaction of the ligands, squaric acid and hydrazine with Ln(NO3)3 where Ln(III) = La, Pr, Nd, Sm, Gd and Ce results in the formation of the complexes of the formula, N2H5[Ln(C4O4)2]xH2O where x = 3, 5 and 6 and their reaction with transition metal nitrates, M(NO3)2xH2O, where M(II) = Co, Ni, Cu, Zn and Cd in aqueous solution yields the squarates of the types, [(N2H5)3M(C4O4)2.5]2H2O where M(II) = Co, Ni and Cd; [(N2H5)2Zn(C4O4)2]2H2O and [(N2H5)Cu(C4O4)1.5 ]. Neutralization of the acid with hydrazine hydrate gives dihydrazinium squarate hydrate, (N2H5)2(C4O4)H2O. All the above complexes, except Cd, are sparingly soluble in water and are characterized by IR, UV-visible, ESR and thermoanalytical methods. The squarates appear to behave as bis-monodentate and tetrakis-monodentate bridged ligands in transition metal and lanthanide complexes respectively. Hydrazinium cation acts as a coordinating ligand in transition metal complexes whereas it is a charge compensating species in lanthanide squarates. This fact is revealed from their IR spectra by displayingN-N frequency at 1000 cm–1 in the former case and at 950 cm–1 in the latter. Squarate compounds exhibit very high exothermic decomposition. Hydrazinium lanthanide squarates show weight losses due to dehydration and dehydrazination from 68 graduate C to 258 graduate C and a strong exothermic decomposition between 176 graduate C and 700 graduate C leading to the formation of metal oxides/oxy carbonates as the end products possibly via H[Ln(C4O4)2] intermediate. Transitionmetal compounds loose water and hydrazine in the range of 50–275 graduate C, and then undergo strong exothermic decomposition above 200 graduate C with no stable intermediate formation. Simple hydrazinium salt decomposes completely exothermally at 179 graduate C. The electronic spectra indicate the coordination number (CN) and geometry; CN 8 with square anti-prism for lanthanides and CN 6 with octahedral arrangement for transition metals. The geometry of the complexes is substantiated by their electronic spectra, magnetic

11

ESR and XRD investigation of effects induced by gamma radiation on PVA-TiO2 membranes

88%

Todica M. , Stefan T. , Trandafir D. , Simon S.

Open Physics

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2013

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tom 11

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nr 7

928-935

EN

The effects of gamma radiation on the local structure of PVA membranes containing TiO2 were investigated by ESR and XRD methods. An intense ESR signal is observed after irradiation at 16 KGy dose. This signal appears only for irradiated samples and it is associated with the breaking of the polymeric chain, followed by local reorganization of the polymeric segments and the apparition of the unpaired electrons and free radicals. The intensity of the signal decreases with the concentration of TiO2, indicating a shielding effect of the dopand. That the modification of local order of the polymeric chains has been modified after irradiation is confirmed by XRD method.

12

The E1' center in natural quartz: its formation and applications to dating and provenance researches

88%

Toyoda S.

Geochronometria

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2011

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tom Vol. 38, no. 3

242-248

EN

Quartz is one of the minerals useful for electron spin resonance (ESR) dating. The E1' center is one of well-known paramagnetic defects in crystalline quartz. This center has a unique feature; its intensity increases on heating. An electronic process to explain this increase was found to be con-trolled not only by the number of oxygen vacancies, which are the precursors, but also by the number of Al hole centers, which depend on the previous radiation dose and on the Al concentration. The maximum intensity on heating is called the heat treated E1' center, which has been posited to correspond to the number of oxygen vacancies in quartz and was found to be correlated with the ages of the host granites (Toyoda and Hattori, 2000). The experimental results on spin-spin relaxation times of the E1' center indicate that external beta and gamma rays create oxygen vacancies in natural quartz rather than alpha or alpha recoil particles (Toyoda et al., 2005). The correlation between the numbers of the oxygen vacancies in quartz and the ages of the host granite made it possible to distinguish the quartz of a sedimentary reservoir from another with different age of crystallization (Toyoda and Naruse, 2002). Quartz fractions extracted from leoss and atmospheric deposition in Japan and from sediments in Japan sea were analyzed by ESR. The temporal change of the contributions from two dust sources in China were discussed in the context of climate change.

13

Taurine-EVA copolymer-paraffin rods dosimeters for EPR high-dose radiation dosimetry

88%

Maghraby A. M. , Mansour A. , Abdel-Fattah A. A.

Nukleonika

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2014

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tom 59

|

nr 1

9-13

EN

Taurine/EPR rods (3 × 10 mm) have been prepared by a simple technique in the laboratory where taurine powder was mixed with a molten mixture of paraffin wax and an ethylene vinyl acetate (EVA) copolymer. The binding mixture EVA/Paraffin does not present interference or noise in the EPR signal before or after irradiation. The rods show good mechanical properties for safe and multi-use handling. An EPR investigation of radiation induced radicals in taurine rods revealed that there are two types of radicals produced after exposure to gamma radiation (60Co). EPR spectra were recorded and analyzed - also the microwave power saturation and modulation amplitude were studied and optimized. Response of taurine to different radiation doses (1.5-100 kGy) was studied and found to follow a linear relationship up to 100 kGy. Radiation induced radicals in taurine persists and showed a noticeable stability over 94 days following irradiation. Uncertainities associated with the evaluation of radiation doses using taurine dosimeters were discussed and tabulated. It was found that taurine possesses good dosimetric properties using EPR spectroscopy in high doses in addition to its simple spectrum.

14

Cost reduction of TiAl by alternative production and integration of TiAl scrap recycling - concepts and vacuum-metallurgical equipment

75%

Lochbichler C. , Friedrich B. , Jarczyk G. , Scholz H.

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2007

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tom Vol. 7, nr 4(14)

81-88

EN

Due to high corrosion resistance and low density titanium aluminides show a great potential as material for structural applications in the aerospace and automotive industry. However the high actual production costs for semi-finished products slow down a break through to mass production of TiAl. Current research projects at IME, Aachen funded by AIF "Otto von Guericke" and BMBF aim on cost reduced production methods of TiAl and on the minimisation of downgrading TiAl scrap. This article presents firstly the state of the art of TiAl production by vacuum arc (re)melting (VAR) or induction skull melting (ISM). A comparison of new process routes under special consideration of recycling issues will follow. Innovative processing and equipment concepts are shown by intelligent combination of well known vacuum melting and remelting processes such as vacuum induction melting, specialized using ceramic lining and deoxidisation with e.g. electro slag re-melting (ESR). For each process step and accordingly equipment the metallurgical opportunities are pointed out and the way to make use of them within the process route is described. Requirements on input material and final metal quality addicted to the processing route and refining techniques with their adjustment in respect to TiAl are mentioned. Selected results of laboratory and pilot scale experiments done at IME in Aachen and equipment needs therefore are shown.

15

Cost reduction of TiAl by alternative production and integration of TiAl scrap recycling - concepts and vacuum-metallurgical equipment

75%

Lochbichler C. , Friedrich B. , Jarczyk G. , Scholz H.

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2008

|

tom Vol. 8, nr 1(15)

67-74

EN

Due to high corrosion resistance and low density titanium alum in ides show a great potential as material for structural applications in the aerospace and automotive industry. However the high actual production costs for semi-finished products slow down a break through to mass production of TiAl. Current research projects at IME, Aachen funded by AIF "Otto von Guericke" and BMBF aim on cost reduced production methods of TiAl and on the minimisation of downgrading TiAl scrap. This article presents firstly the state of the art of TiAl production by vacuum arc (re)melting (V AR) or induction skull melting (ISM). A comparison of new process routes under special consideration of recycling issues will follow. Innovative processing and equipment concepts are shown by intelligent combination of well known vacuum melting and remelting processes such as vacuum induction melting, specialized using ceramic lining and deoxidisation with e.g. electro slag remelting (ESR). For each process step and accordingly equipment the metallurgical opportunities are pointed out and the way to make use of them within the process route is described. Requirements on input material and final metal quality addicted to the processing route and refining techniques with their adjustment in respect to TiAl are mentioned. Selected results of laboratory and pilot scale experiments done at IME in Aachen and equipment needs therefore are shown.

16

Laccase action on kraft pulp lignin in chlorine free bleaching process

75%

Surma-Ślusarska B. , Leks-Stępień J. , Bednarek J. , Płonka A.

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1999

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tom Vol. 47, No. 3

187-192

EN

Results of ESR measurements of the kraft pulp lignin during its oxidation with laccase and the properties of the bleached pulp are presented.

17

Lipid radicals: Properties and detection by spin trapping.

75%

Stolze K. , Udilova N. , Nohl H.

Acta Biochimica Polonica

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2000

|

tom 47

|

nr 4

923-930

EN

Unsaturated lipids are rapidly oxidized to toxic products such as lipid hydroperoxides, especially when transition metals such as iron or copper are present. In a Fenton-type reaction Fe2+ converts lipid hydroperoxides to the very short-lived lipid alkoxyl radicals. The reaction was started upon the addition of Fe2+ to an aqueous linoleic acid hydroperoxide (LOOH) emulsion and the spin trap in the absence of oxygen. Even when high concentrations of spin traps were added to the incubation mixture, only secondary radical adducts were detected, probably due to the rapid rearrangement of the primary alkoxyl radicals. With the commercially available nitroso spin trap MNP we observed a slightly immobilized ESR spectrum with only one hydrogen splitting, indicating the trapping of a methinyl fragment of a lipid radical. With DMPO or 5-diethoxyphosphoryl-5-methyl-1-pyrroline N-oxide (DEPMPO) adducts were detected with carbon-centered lipid radical, with acyl radical, and with the hydroxyl radical. We also synthesized lipophilic derivatives of the spin trap DEPMPO in order to detect lipid radical species generated in the lipid phase. With all spin traps studied a lipid-derived carbon-centered radical was obtained in the anaerobic incubation system Fe2+/LOOH indicating the trapping of a lipid radical, possibly generated as a secondary reaction product of the primary lipid alkoxyl radical formed. Under aerobic conditions an SOD-insensitive oxygen-centered radical adduct was formed with DEPMPO and its lipophilic derivatives. The observed ESR parameters were similar to those of alkoxyl radical adducts, which were independently synthesized in model experiments using Fe3+-catalyzed nucleophilic addition of methanol or t-butanol to the respective spin trap.

18

Filtrowanie stali stopowych w próżni jako alternatywna technologia elektrożużlowego przetapiania

51%

Pogorzałek J. , Galisz U. , Bulkowski L. , Marcisz J.

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2006

|

tom T. 58, nr 3

34-40

PL

Użytkownicy wyrobów stalowych wymagają często do określonych zastosowań tzw. stali "czystych" (o bardzo małej ilości i wielkości wtrąceń niemetalicznych). Jednym ze sposobów wyprodukowania "czystej" stali jest technologia elektrożużlowego przetapiania (EŻP). Na przestrzeni lat intensywnie rozwijała się też technologia wytapiania czystych stali w próżniowym piecu indukcyjnym (PPI) oraz technologia filtrowania stali przez filtry ceramiczne, w której następuje głębokie oczyszczenie stali z wtrąceń niemetalicznych. W IMŻ przeprowadzono próby połączenia technologii PPI z filtracją stali w warunkach obniżonego ciśnienia uzyskując stal o porównywalnej jakości do stali po EŻP.

EN

The users of steel products often require so-called pure steels (with a very small amount and size of non-metallic inclusions) for specific applications. One of the methods for making "pure" steel is the electroslag remelting technology (ESR). Over the years, there was also developing the technology for melting steel in the vacuum induction furnace (PPI) and technology for filtering steel through ceramic filters in which deep steel purification of non-metallic inclusions takes place. In the Institute for Ferrous Metallurgy, the attempts to combine PPI technology and steel filtration under the reduced pressure conditions were made. The result was obtaining the steel of quality comparable to the quality of steel after ESR.

19

Radiation proceses in poly(ethylene terephthalate) composite materials

51%

Sadło J. , Bojarski J. , Strzelczak G. , Michalik J.

|

1999

|

tom Vol. 44, nr 1

59-69

EN

The radiation - induced radicals in poly(ethylene terephthalate) - PET composite with polypropylene - PP and polyetherester KPEE have been studied by ESR spectroscopy. In pure PET matrix radicals are not stabilized at room temperature but in PET/PP composite (10-20% of PP) similary to pure PP matrix peroxy radicals are recorded at room temperature with the concentrations indicating that radicals formed originally in PET units are stabilized during migration along polymer chain by PP units enabling the formation of peroxy radicals. In contrast, in PET/KPEE composite materials the radical processes are the same as in PET homopolymers. The changes of polymer viscosity in melting state prove that polymer degradation is major radiation effect in the majority of composite materials.

PL

Przy użyciu spektroskopii Elektronowego Rezonansu Paramagnetycznego (EPR) badano inicjowane radiacyjnie rodniki w kompozytach polimerowych na bazie politereftalanu etylenu (PET) z domieszką polipropylenu (PP) lub kopolieteroestru (KPEE). W czystym PET wolne rodniki w temperaturze pokojowej nie stabilizują się, natomiast w kompozytach PET/PP zawierających 10 i 20% PP rejestruje się, podobnie jak w czystym PP, rodniki nadtlenkowe. Stężenie rodników w tych kompozytach jest większe niż procentowy udział polipropylenu w matrycy polimerowej. Wskazuje to, że rodniki powstające początkowo we fragmentach politereftalanowych migrują wzdłuż łańcuchów ulegając stabilizacji we fragmentach polipropylenowych w wyniku powstawania rodników nadtlenkowych. Efektu tego nie obserwuje się w kompozytach PET/KPEE, w których procesy rodnikowe przebiegają w ten sam sposób jak w homopolimerze PET. Na podstawie zmian lepkości polimerów w stanie stopionym stwierdzono, że w badanych polimerach głównym efektem radiacyjnym jest degradacja.