Influence of storage conditions on starch/PVA films containing cellulose nanofibers

What is it about?

Cellulose nanofibers (CN) with high aspect ratio were obtained and their transverse modulus was determined for the first time by QNM (Quantitative Nanomechanical Mapping) mode of AFM. The value of the transverse modulus (18.8 GPa) was comparable with that of cellulose determined by other methods. CN were used as reinforcements in starch/poly(vinyl alcohol) (S/PVA) crosslinked films and the influence of storage conditions on the properties of these films was investigated. It was found that over 4 wt%, CN form a network and hinder starch recrystallization. CN determined a significant increase of strength and stiffness of S/PVA depending on storage conditions. Starch films with 7 wt% CN showed strength and stiffness close to that of polyolefines (19.5 MPa and 1199 MPa, respectively) and can be seen as a low cost “green” substitute for application in food packaging and conservation.

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Why is it important?

Starch/polyvinyl alcohol composites have been investigated for the production of “green materials” for packaging or agricultural applications. For this purpose, simultaneous crosslinking and cellulose nanofibers (CN )addition were applied. Starch granules were completely gelatinized in S/PVA and nanocomposites and their crystalline structure was changed. This work provides a simple route to prepare starch films with good mechanical properties and reduced sensitivity to water.