preparation and characterization of cellulose nanofoam composite based on Starch

Starch is an attractive biofoam candidate as replacement of expanded polystyrene (EPS) in packaging materials. The main technical problems with starch foam include its hygroscopic nature, sensitivity of its mechanical properties to moisture content, and much lower energy absorption than EPS. Starch is biodegradable but very brittle and has poor mechanical properties. It is, therefore, a poor alternative for any synthetic thermoplastic. However, there are several ways to improve some properties of the starch, such as blending them with other polymers such as polylactic acid, polyethylene and polyvinyl alcohol. Another way of improving the thermal and mechanical properties of starch may be the addition of natural fillers. The main goal of the present work is to produce and characterize the bio-nanocomposites foam from wheat straw nanofibers and thermoplastic starch polymer. Starch was chosen as a polymer matrix because of its biodegradability. The biofoams are prepared by the freezing/freeze-drying technique. Cellulose nanofibers were extracted from wheat straw by a chemical treatment, resulting to purified cellulose, followed by a mechanical treatment in order to individualize nanofibers from the cellulose bundles.