Akademik Veri Yönetim Sistemi
Tezin Türü: Yüksek Lisans
Tezin Yürütüldüğü Kurum: Marmara Üniversitesi, Fen Bilimleri Enstitüsü, Fizik Anabilim Dalı, Türkiye
Tezin Onay Tarihi: 2023
Tezin Dili: İngilizce
Öğrenci: ASEEL MOHAMMAD ISMAIL ALMASHAYEK
Asıl Danışman (Eş Danışmanlı Tezler İçin): Uğur Yahşi
Özet:
RELAXATION TIME OF SOME MELT POLYMERS IN TERMS OF HOLE FRACTION COMPUTED FROM SIMHA SOMCYNSKY THEORY The correlation between the relaxation behavior of polymers and the related temperature and pressure changes is the sequel to the research area on the statistical thermodynamics of macromolecules based on their type, shape, and a number of branches that have been essential with new architectures. In our study, we bridge two theories: Simha-Somcynsky hole theory as equilibrium theory and Eyring significant structure theory as transport theory. We interpret transport phenomena such as the relaxation time in terms of the hole fraction, which is a measure of the free volume, as an equilibrium property. We will employ PVAc (poly vinyl acetate) (Mw = 93 080 g/mol) with the available data in specific volume and relaxation time measured in some range of temperature and pressure. We have employed a theoretical model recently proposed for the relaxation time of polymers using the transport theory of Eyring Significant Structure (ESS) and the equilibrium theory of Simha-Somcynsky. An analysis of the structural relaxation of chain molecules as determined by the 'thermo-occupancy' function is presented and compared with the free volume model based on the temperature and temperature‒pressure dependence of the hole fraction. Our study examines the relaxation time of PVAc as a function of the hole fraction at different temperatures and pressures. In addition to discussing the logarithm of relaxation with respect to the hole fraction, we have also discussed relaxiholibility (derived from relaxation and hole fraction), which is expected to decrease or increase as the hole fraction changes.