Akademik Veri Yönetim Sistemi
Tezin Türü: Yüksek Lisans
Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Türkiye
Tezin Onay Tarihi: 2014
Tezin Dili: İngilizce
Öğrenci: Büşra Akınalan
Eş Danışman: NECATİ ÖZKAN, UFUK BÖLÜKBAŞI
Açık Arşiv Koleksiyonu: AVESİS Açık Erişim Koleksiyonu
Özet:Today, due to the environmental concerns about petroleum based polymers, the use of renewable polymers including polysaccharides in food packaging applications is increasing rapidly. In the present study, hemicellulose was extracted from corn cobs, wheat straw and sunflower stalks, and two different techniques, solvent casting and extrusion, were utilized for biodegradable film production. Films produced from different types of biomasses were compared in terms of their mechanical, thermal and morphological properties while studying the process parameters of extraction temperature, extrusion temperature and screw speed. Film formation was achieved by extrusion from all the hemicelluloses. Increasing the extrusion temperature had a slightly positive effect on the mechanical properties of films, whereas screw speed did not have a noticeable effect. Hemicellulose extraction at room temperature is determined a better temperature than 60°C in terms of mechanical properties of films. Among the films produced via extrusion, corn cob hemicellulose extracted at room temperature showed the best mechanical properties depending on Ara/Xyl ratio of hemicelluloses, with a toughness of 13MJ/m3 ,while the toughness value of the sunflower stalk based films were relatively poor, which was 2MJ/m3 . On the other hand, homogenous and strong films with a tensile strength of 107 MPa were obtained from the same sunflower stalk hemicellulose when solvent casting technique was used. The onsets of thermal degradation temperature for solvent casted and extruded films were determined via TGA as 300°C for corn cob and wheat straw hemicellulose and 296°C for the films produced from sunflower stalk hemicellulose. The films were mostly homogenous and crack-free except for the sunflower stalk films extruded at 75°C as observed via SEM analysis.