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Wyszukujesz frazę "Mirkowski, K." wg kryterium: Autor


Wyświetlanie 1-4 z 4
Tytuł:
Effect of hindered amine light stabilizers on the resistance of polypropylene towards ionizing radiation
Autorzy:
Przybytniak, G.
Mirkowski, K.
Rafalski, A.
Nowicki, A.
Legocka, I.
Zimek, Z.
Powiązania:
https://bibliotekanauki.pl/articles/148686.pdf
Data publikacji:
2005
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
polypropylene
stabilizers
HALS
electron beam
apparent viscosity
nucleation agent
Opis:
The influence of hindered amine light stabilizers (HALSs) on physical and mechanical properties of irradiated and non-irradiated isotactic polypropylene (PP) was studied. The stabilizers under investigation were: Tinuvin 765 (T765) and Tinuvin 622 (T622) - derivatives of 1,2,2,6,6-pentamethyl piperidine and Chimassorb 944 (C944) - a derivative of 2,2,6,6-tetramethyl piperidine. It was found that the stabilizers reduce the amount of peroxyl radicals in the amorphous phase of PP. The irradiation with electron beam causes a drop of apparent viscosity both in the original and in the modified PP however the effect is smaller in the presence of HALSs. Admixture of T622 and T765 stabilizers increases the crystallization temperature of non-irradiated PP by about 8 10°C (measured by DSC) what results from the facilitated formation of a large number small microcrystals. It was concluded that HALSs initiate two opposite tendencies - chemical protection against damage initiated by free radicals and, simultaneously, physical enhancement of sensitivity towards irradiation by the increase of nucleation density. In the studied systems, the presence of maleic anhydride does not improve compatibility between the polymeric matrix and HALSs.
Źródło:
Nukleonika; 2005, 50, 4; 153-159
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of polymers designed for radiation processing
Autorzy:
Przybytniak, G.
Nowicki, A.
Mirkowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/148299.pdf
Data publikacji:
2008
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
polyethylene
radiation processing
cross-linking
Opis:
Five types of commercially available polyethylene (PE) and some selected blends with components supporting cross-linking were radiation cross-linked. Mechanical properties and gel fraction were determined upon electron beam irradiation to such a dose that induces about 60% gel fraction. It was confirmed that for easily cross-linked PEs strength at break usually was growing and for polyethylenes less susceptible to radiation cross-linking – was reduced. Similar dependence was found for elongation at break. It was confirmed that for polyethylenes demonstrating high strength at break the efficiency of radiation cross-linking is limited. Additionally, for selected polymeric materials, stress relaxation and accelerated thermal aging were estimated. In order to enhance cross-linking yield some blends with EVA copolymer (ethylene-vinyl acetate) were prepared. On the basis of the literature data, the influence of crystalline regions on cross-linking and mechanical properties was discussed as well.
Źródło:
Nukleonika; 2008, 53, suppl. 2; 67-72
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Functionalization of polymer surfaces by radiation-induced grafting
Autorzy:
Przybytniak, G.
Kornacka, E. M.
Mirkowski, K.
Walo, M.
Zimek, Z.
Powiązania:
https://bibliotekanauki.pl/articles/146746.pdf
Data publikacji:
2008
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
radiation grafting
EPR
radicals
radiation yield
Opis:
The mutual radiation grafting of acrylic acid (AAc) onto polyethylene (PE), polypropylene (PP) and polystyrene (PS) films was performed. At first stage of investigations, the influence of ionizing radiation on the trunk polymers was studied, i.e. the level of radicals stable at room temperature and radiation yield of evolved hydrogen were estimated for each polymer. The measurements were carried out using electron paramagnetic resonance (EPR) spectroscopy and gas chromatography (GC), respectively. Radiation yields of radicals as well as hydrogen emission increased in the following order PS < PP < PE. Under comparable conditions, the same relationship was found for the yield of radiation-induced grafting of AAc. A distinct correlation between content of radicals generated by ionizing radiation in polymeric matrices and grafting degree was confirmed for the studied materials. The effect of monomer and inhibitor concentrations on the efficiency of processes were studied as well.
Źródło:
Nukleonika; 2008, 53, 3; 89-95
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model studies on phenolic antioxidant role in radiation - and thermally - induced accelerated degradation of electrical cable insulation
Autorzy:
Boguski, J.
Przybytniak, G.
Mirkowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/146778.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
antioxidant
radiation
degradation
aging
polyethylene
Irganox 1035
Opis:
The main objective of this work was to establish a correlation between radiation- and thermally-induced changes in polyethylene and the amount of compounded phenolic antioxidant (Irganox 1035). Radiation yield of oxygen consumption, oxidative induction time and gel fraction allowed to estimate the utility of the applied experimental methods to monitor oxidative aging of the polymeric material from the standpoint of cable and wire degradation in nuclear power plants. It was found that the phenolic antioxidant not only inhibits chain oxidation but also changes the mechanisms of radical processes influencing significantly capability of polyethylene towards thermally-induced cross-linking.
Źródło:
Nukleonika; 2012, 57, 4; 485-489
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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