Preparation and characterization of bionanocomposites based on proteins and cellulose nanocrystals by continuous casting

Abstract

The increasing level of environmental awareness regarding the inappropriate disposal of non-biodegradable packaging, as well as the opportunity to create new markets for raw film-forming materials, stimulate the development of edible and/or biodegradable packaging materials. Proteins can be used as a polymer matrix for the production of edible and biodegradable packagings with differentiated physical, sensory and nutritional properties. However, using only proteins is not enough for producing films with satisfactory mechanical and barrier properties for food packaging usage. The preparation of bionanocomposites reinforced with cellulose fillers, such as cellulose nanocrystals (CNC), is an alternative that has been extensively studied in order to increase the properties of these polymer films. Therefore, this PhD project proposes the production, characterization and optimization of new edible films based on proteins (i.e. collagen, soy and whey) and cellulose nanocrystals using the continuous casting method. The main goal is to research the morphology and dispersion of cellulose nanocrystals in protein matrices, as well as the effect of the CNC addition in terms of mechanical, thermal and barrier properties of films processed by continuous casting. Rheological measurements will be made to the protein solutions in order to design and optimize processing conditions for obtaining films. Several characterization techniques will be used for analyzing the structural and morphological characteristics of the obtained cellulose nanocrystals and bionanocomposites, including FTIR spectroscopy, X-ray diffraction, colorimetric, spectroscopy UV/VIS, and scanning and transmission electronic microscopy. Furthermore, thermal stability of bionanocomposites will be investigated by differential scanning calorimetry and thermogravimetric analysis, as well as the mechanical and barrier properties. (AU)