Çift Vidalı Ekstrüder Yardımı ile Farklı Oranlarda Polimerik Filmlerin Sentezlenmesi ve Bu Filmlerin Kontrollü Kompost Ortamında Biyobozunmalarının İncelenmesi

Abstract

ABSTRACT SYNTHESIS OF POLYMER FILMS AT DIFFERENT RATIOS BY USING TWIN SCREW EXTRUDER AND INVESTIGATION OF THEIR BIODEGRADABILITY UNDER CONTROLLED COMPOSTING CONDITIONS Selin Cansu ŞEN Master of Science, Department of Chemical Engineering Supervisor: Prof. Dr. Hülya YAVUZ ERSAN September 2015, 71 pages Polymers are significant materials that find place in various applications. That’s why the production rate of polymers reaches a million tones per year. Nowadays polymers are mainly produced from petroleum products and natural gas which not renewable sources. Moreover polymer wastes are an important solid waste issue to deal with. Especially in some processes, tones of synthetic polymers are being used for the production of packaging material and after a very short time of all these polymers became solid waste. This significant environmental issue compels scientists to improve eco-friendly techniques and bio-based materials. In line with this objective, to produce packaging materials from bio-based polymers become inevitable. Starch is one of the mostly produced biopolymers in the world. It is being used in many important industries as pulp and paper, textile and farmocology due to its biocompatibility and biodegradability. However, due to its weak mechanical properties it is preferred to use starch together with another polymer having good mechanical properties. Polylactic acid (PLA) which is reproduced from renewable sources, compostable, biodegradable and biocompatible, is one of the polymers that is used with starch. The superior mechanical properties of PLA and increase in the environmental consciousness make PLA the leading biopolymer that

preferred for this purposes and rapidly increased the number of studies performed by these polymers. But existing studies about the degradation of the starch/PLA polymer in composting process are not enough to explain the degradation mechanism. Thus there is a need for new studies to improve performance degradation process and to decrease the degradation time. In this study starch-g-LA polymer that composed of different amounts of lactic acid was fabricated by the help of twin screw extruder. The biodegradation properties of these polymer were examined in controlled composting conditions according to the ISO 14855:1, 2013 standard. The released CO2 along the composting process was measured by stabilizing the reactor conditions as temperature, humidity and amount of O2. Degradation mechanism of fabricated polymer was tried to be lightened via the examination of the physical, chemical, thermal and morphological properties. In order to provide the reaction between starch and lactic acid any toxic solvent was not used. The fabrication of starch-PLA polymer by shear mixing and reactive extrusion methods and the investigation of biodegradation of this polymer under controlled composting conditions were performed for the firs time by this study. The characterization of polymer films that produced by blow molding extrusion method was performed by by FT-IR Spectroscopy, C-NMR Spectroscopy, XRD, TGA/DTG and SEM techniques. The films fed into the compost bioreactors were characterized by FT-IR, TGA/DTA and SEM techniques at the end of the composting process. Keywords: starch, lactic acid, graft copolymer, shear mixing, reactive extrusion, biodegradation, composting