A cellulose nanocomposite biopolymer foam competing with expanded polystyrene (EPS): hierarchical structure effects on energy absorption
(English)Manuscript (Other academic)
Starch is an interesting 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. In the present study, a starch-based biofoam is able to reach comparable mechanical properties (Young’s modulus, compression yield strength) to expanded polystyrene at 50% relative humidity. The reason is the cellulose nanocomposite concept in the form of a cellulose nanofiber network reinforcing the hygroscopic amylopectin matrix in the cell wall. The biofoams are prepared by freeze-drying and subjected to compressive loading. Cell structure is characterized by FE-SEM of cross-sections. Mechanical properties are related to cell structure and cell wall nanocomposite composition. Hierarchically structured biofoams are demonstrated to be interesting materials with potential for strongly improved mechanical properties. The present study also highlights the challenges involved in preparation and analysis of nanocomposite foams structured at several different scales.
IdentifiersURN: urn:nbn:se:kth:diva-9655OAI: oai:DiVA.org:kth-9655DiVA: diva2:126837
QC 201009132008-11-262008-11-242010-09-13Bibliographically approved