Tez özetleri Astronomi ve Uzay Bilimleri Anabilim Dalı 2

Investigation Of Crystallization Properties Of Poly(Ethylene Terephthalate)-Polypropylene Blends
Polymer materials are appreciated for their chemical, physical and economical qualities. Material needs of developing technology require that the materials should have more excellent performances. For this purpose, polymers that have different characteristics have been mixed and blends can be prepared. Crystallization is very important feature that affect the psysical and mechanical properties in polymers and polymer blends.
In this study, crystallization properties of structures that are obtained by mixing different amounts of components of poly(ethylene terephthalate) (PET) – polypropylene (PP) blends are investigated. Maleic anhydre grafted PP (PP-g-MAH) was used as compatibilizer. The purpose of this study is to investigate the effect of component ratios in PET – PP mixtute and the existance of compatiblizer on the crystalization kinetics.
Samples of this study are prepared previously using granule PET and isotactic PP with the method of melt mixing in a single screw extruder including a static mixer. The weight ratios of PET/PP for incompatibilized PET-rich, PET/PP equal, and PP-rich compositions were 80/20, 50/50 and 20/80, respectively. PET/PP/PP-g-MAH ratio for compatibilized PP-rich blend was 19/76/5 and for compatibilized PET/PP equal blend was 47.5/47.5/5.
Differential Scanning Calorimetry (DSC) analyses were carried out in order to investigate nonisothermal crystallization kinetics of PET-PP blends. Crystallization percentages of the blend samples and crystallization behaviors were investigated by using different cooling rates and kinetic constants were calculated by using different kinetic models.

Relative values of crystallization were calculated by the integration of the area under the crystallization curve of DSC. Relative crystallization values for each cooling rate were obtained from relative crystallization-temperature curves.

Crystallization behaviors of the samples were evaluated by Avrami equation and Ozawa and Liu-Mo models that are derived from this equation. Kinetic rate constants were found by using Jeziorny equation which is derived for evaluation of Avrami equation at nonisothermal conditions. Since Ozawa modelling gave nonlinear curves, Ozawa constants could not be evaluated. Besides, kinetic constants from figures of Liu-Mo equation were found and discussed. Finally, crystallization activation energies were obtained by using Kissinger method.

EROL Gizem

Danışman : Prof. Dr. İsmail İNCİ

Anabilim Dalı : Kimya Mühendisliği

Programı : Temel İşlemler ve Termodinamik

Mezuniyet Yılı : 2014

Tez Savunma Jürisi : Prof. Dr. İsmail İNCİ

Prof. Dr. Mehmet BİLGİN

Doç. Dr. Tülin B. İYİM

Doç. Dr. Nihal Y. ONUL

Y. Doç. Dr. Tuba G. ALTINÇEKİÇ