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Information × Registration Number 0214U005519, 0113U006261 , R & D reports Title Investigation of defect structure in ion-implanted polymeric materials popup.stage_title Head Kavetskyy Taras Stepanovych, Кандидат фізико-математичних наук Registration Date 23-01-2014 Organization Drohobych Ivan Franko State Pedagogical University popup.description2 The investigations of defect structure performed in the boron ion implanted polymer polymethylmethacrylate (PMMA) with using conventional positron annihilation spectroscopy methods – positron annihilation lifetime spectroscopy and Doppler broadening of annihilation line in the temperature range of 50-300 K – indicate clear an existence of two transitions nearby 150 and 250 K, connected from literature with gamma and betha processes (transitions) in the PMMA matrix. For the first time, it is observed a decreasing of the molecular weight of polymer PMMA at lower ion doses (< 10^16 ion/cm2). At higher ion dose (> 10^16 ion/cm2) a local destruction of polymer structure takes place resulting in broadening of free-volume (voids) distribution in the PMM matrix. At the same time, the investigations of defect structure carried out in the boron ion implanted polymer PMMA with using theoretical SRIM simulation and unique slow positron beam spectroscopy methods – Doppler broadening of annihilation line in dependence on the positron energy in the range of 0-30 keV and positron annihilation lifetime spectroscopy at fixed positron energy 2.15 keV– for the first time, allow confirming the existence of the expected two processes: appearance of free radicals preceding the aggregation of the clusters resulting in the formation of network of conjugated bonds at lower ion doses and carbonization at higher ion doses. Product Description popup.authors Виграновський Володимир Орестович Кавецька Надія Маркіянівна Кавецький Орест Степанович Кавецький Тарас Степанович Ковтало Оксана Романівна Пігур Оксана Михайлівна Петрицина Юлія Іванівна Цмоць Володимир Михайлович popup.nrat_date 2020-04-02 Close