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18. Atom transfer radical polymerization grafting of highly functionalized polystyrene and poly(4-methylstyrene) macroinitiators with <TOGGLE>tert</TOGGLE>-butyl acrylate

Author

Masař, Bohumil, Janata, Miroslav, Vlček, Petr, Toman, Luděk, and Kurková, Dana

Abstract

Two monodisperse graft copolymers, poly(4-methylstyrene)-graft-poly(tert-butyl acrylate) [number-average molecular weight (Mn) = 37,500, weight-average molecular weight/number-average molecular weight (Mw/Mn) = 1.12] and polystyrene-graft-poly(tert-butyl acrylate) (Mn = 72,800, Mw/Mn = 1.12), were prepared by the atom transfer radical polymerization of tert-butyl acrylate catalyzed with Cu(I) halides. As macroinitiators, poly{(4-methylstyrene)-co-[(4-bromomethyl)styrene]} and poly{styrene-co-[4-(1-(2-bromopropionyloxy)ethyl)styrene]}, carrying 40% of the bromoalkyl functionalities along the chain, were used. The dependencies of molecular parameters on monomer conversion fulfilled the criteria for controlled polymerizations. In contrast, the dependencies of monomer conversion versus time were nonideal; possible causes were examined. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2930–2936, 2002

Published
2002
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19. Temperature Induced Conformational Transitions of Elastin-Like Polypentapeptides Studied by Raman and NMR Spectroscopy

Author

Dybal, Jirí, Schmidt, Pavel, Kurková, Dana, Kríž, Jaroslav, Carlos Rodríguez-Cabello, José, and Alonso, Matilde

Abstract

Raman and NMR spectroscopy together with DFT quantum chemical calculations have been used to elucidate conformational changes occurring during inverse temperature transition in water solution of two elastin-like polypentapeptides, poly(G1V1G2V2P) and poly(AV1GV2P). From the temperature dependences of Raman spectra and 1H–1H NOESY spectra follows that above the transition temperature a β(II)-turn conformational structure is formed on the residue located between Pro and Val1.

Published
2002
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20. Comparison of luminescence detectors of Al 2 O 3 :C, CaF 2 :Mn, LiF:Mg,Cu,P and quartz with respect to retrospective dose reconstructions using bricks.

Author

Ekendahl D, Kurková D, Judas L, Čemusová Z, Reimitz D, Kubínová M, Kapuciánová M, and Hupka I

Abstract

In the aftermath of an orphan radiation source find, a complex retrospective dose reconstruction can be required to estimate doses of persons who were staying in the vicinity. In retrospective dose reconstructions based on luminescence measurements of quartz extracted from bricks, high sensitivity thermoluminescence detectors (TLD) can be used as an ancillary tool for dose distribution measurements or natural radiation background measurement. We investigated the potential and limits of Al 2 O 3 :C, CaF 2 :Mn and LiF:Mg,Cu,P detectors for such applications. We measured depth-dose profiles in bricks using quartz and the TLDs. We factored in important dosimetry characteristics such as dose response, energy response and detection threshold. The work included Monte Carlo simulations. Depth-dose profiles and radiation spectra inside of the bricks were calculated for purposes of comparison and interpretation. The measurements and calculations were performed for two different photon spectra with mean energies of 662 and 118 keV. As regards comparison of the measured and Monte Carlo calculated depth-dose profiles, the best agreement was found for LiF:Mg,Cu,P. Quartz, Al 2 O 3 :C and CaF 2 :Mn tend to overestimate dose for lower photon energies and greater depths in bricks. The overestimation was the most marked for CaF 2 :Mn. For measurements related to quartz, especially for natural radiation background dose measurement, the most suitable TLDs are Al 2 O 3 :C and LiF:Mg,Cu,P. CaF 2 :Mn is the least useful material., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Published
2021
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