Defense of Doctoral Thesis with Pegah Khanjani, Aalto University, Finland, April 2019

Title of Thesis: Development of novel methods for production of cellulose-based materials

Abstract: Modern technology requires sustainable solutions for future new applications. Different types of cellulose such as cellulose nanocrystals (CNCs) and microfibrillated cellulose (MFC) are of particular interest as renewa-ble, highly functionalizable and widely available raw materials. In this thesis, various novel methods for the production of cellulose-based materials were explored. The main findings of this study can be divided into two parts: (i) introducing a method for assessing the reactivity of cellulose in chemical pulps and bacterial cellulose (BC) under mild conditions (RT and pH 9) (Paper I) and ii) investgating several approaches for the chemical functionalization of cellulose as an easy way to adjust the prop-erties of the macromolecule for various purposes. Esterification of cellu-lose with long-chain aliphatic acid chloride is an effective technique for enhancing the hydrophobicity of cellulose, which can then be used as a coating (Paper II). Another crucial route of cellular functionalization is TEMPO-mediated oxidation, which forms carboxyl groups on the surface of MFC. Crosslinking of these carboxyl groups with metal ions under specific conditions leads to increased tensile strength of the cellulosic film (Paper III and IV). The results yield different approaches to the cellulose reactivity and to improve the water-resistance and tensile strength of the paper and Films, respectively, which may create many renewable options in various applications to replace fossil raw materials.

Keywords:cellulose nanocrystalsmicrofibrillated cellulosepulpreactivityTEMPO-mediated oxidationesterificationfilm

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