Effect of chitosan on the behaviour of the wheat B-starch nanocomposite

The combination of a tiny amount of chitosan and montmorillonite represents a promising method to improve the mechanical and barrier properties of thermoplastic starch. These improvements have been demonstrated in the thermoplastic starch derived from wheat B-starch, which is a low-quality by-product in the starch industry. The combination of 0.6% CS and 3% clay leads to a film that has a tensile strength value of 34 MPa, which indicates synergistic effects of the CS/clay combination. These effects were also reflected in the reduced permeability for oxygen and enhanced thermal stability. However, the hydrophilicity of both added components resulted in increased water vapour absorption. Because the TEM observations and XRD patterns indicate a quite similar degree of clay exfoliation of all the investigated nanocomposites, the effect of CS primarily consists of modifying the matrix and improving the interfacial properties due to the strong potential of the amino groups in the CS for polar interaction/ionic exchange with the nanosilicate.

Figure optionsDownload as PowerPoint slideHighlights
► A valuable thermoplastic material derived from secondary B-starch.
► Enhanced properties via addition of small amounts of chitosan and/or montmorillonite.
► Synergistic effects between the additives were reflected in the reduced permeability.
► Easy, one-step preparation.