"14"^^ . "14"^^ . . "GA203/02/1243" . "Neuvedeno."@en . . . . "Prostorov\u00E9 rozli\u0161en\u00ED degrada\u010Dn\u00EDho procesu v pevn\u00FDch polymerech technikou prostorov\u00E9ho zobrazen\u00ED elektronov\u00E9 spinov\u00E9 rezonance" . . . "0"^^ . . "1"^^ . . . . "Nitroxide radicals are considered key intermediates in the protection mechanism of hindered amine stabilizers (HAS) during degradation processes in bulk polymers. We propose the use of the electron spin resonance imaging (ESRI) technique for determination of concentration profiles of nitroxides in polymer sheets subjected to accelerated weathering. The profiles will be measured in the direction of incident radiation (perpendicular to the sheet surface) in dependence on both the polymer and HAS type, HAS concentration, and conditions and duration of the accelerated weathering process. The aim of the project is to elucidate the unknown light- and thermal-induced physical and chemical phenomena in the mechanism of HAS activity in the solid polymer matrix. The ESRI data will be completed with data characterizing changes of selected mechanical (impact strength, elongation, tensile strength) and chemical (formation of carbonyl and hydroxy groups, yellowness index) characteristics of polymers"@en . . "An electron spin resonance imaging (ESRI) technique has been developed for measurement of concentration profiles of nitroxide radicals generated from hindered amine stabilizers (HAS) in polymer plaques subjected to photodegradation. Different shapes of n"@en . . . . . "Spatial resolution of degradation processes in bulk polymers by electron spin resonance imaging"@en . "2008-06-02+02:00"^^ . . "http://www.isvav.cz/projectDetail.do?rowId=GA203/02/1243"^^ . . "0"^^ . . "Vypracovali jsme metodu m\u011B\u0159en\u00ED koncentra\u010Dn\u00EDch profil\u016F nitroxidov\u00FDch radik\u00E1l\u016F v\u00A0polymern\u00EDch desti\u010Dk\u00E1ch technikou prostorov\u00E9ho zobrazen\u00ED elektronov\u00E9 paramagnetick\u00E9 rezonance (ESRI). Nitroxidy vznikaj\u00ED v\u00A0polymerech p\u0159em\u011Bnou stabiliz\u00E1tor\u016F na b\u00E1zi stericky st"@cs . "Nitroxidov\u00E9 voln\u00E9 radik\u00E1ly jsou kl\u00ED\u010Dov\u00FDmi meziprodukty v mechanismu p\u016Fsoben\u00ED stabiliz\u00E1tor\u016F p\u0159ipraven\u00FDch na b\u00E1zi st\u00EDn\u011Bn\u00FDch amin\u016F (HAS) v pr\u016Fb\u011Bhu degrada\u010Dn\u00EDch proces\u016F v polymerech. Navrhujeme pou\u017E\u00EDt techniku prostorov\u00E9ho zobrazen\u00ED elektronov\u00E9 spinov\u00E9 rezonance (ESRI) k ur\u010Den\u00ED koncentra\u010Dn\u00EDch profil\u016F nitroxidov\u00FDch radik\u00E1l\u016F uvnit\u0159 polymern\u00EDch vzork\u016F ve tvaru desti\u010Dek vystaven\u00FDch urychlen\u00E9mu st\u00E1rnut\u00ED. Profily budou m\u011B\u0159eny pod\u00E9l sm\u011Bru dopadaj\u00EDc\u00EDho z\u00E1\u0159en\u00ED (kolmo k povrchu desti\u010Dky) v pr\u016Fb\u011Bhu st\u00E1rnut\u00ED vzorku v z\u00E1vislosti na typu jak polymeru tak HAS, na koncentraci HAS a na podm\u00EDnk\u00E1ch a dob\u011B trv\u00E1n\u00ED procesu urychlen\u00E9ho st\u00E1rnut\u00ED. C\u00EDlem projektu je p\u0159isp\u011Bt k objasn\u011Bn\u00ED foto a termo fyzik\u00E1ln\u00EDch a chemick\u00FDch procesu v mechanizmu p\u016Fsoben\u00ED HAS v pevn\u00E9 polymern\u00ED matrici. Data z\u00EDskan\u00E1 ESRI technikou budou dopln\u011Bna daty charakterizuj\u00EDc\u00EDmi zm\u011Bny vybran\u00FDch mechanick\u00FDch a chemick\u00FDch parametr\u016F charakterizuj\u00EDc\u00EDch polymery v pr\u016Fb\u011Bhu urychlen\u00E9ho st\u00E1rnut\u00ED. Hlub\u0161\u00ED pochopen\u00ED chemick\u00FDch a fyzik\u00E1ln\u00EDch procesu je" . .