Growing concern about the preservation of the environment has encouraged the use of bio-based degradable polymers. Among these, starch has been generating a lot of interest recently due to its biodegradability and high biocompatibility with the human body. Starch-based biodegradable materials cover a wide range of applications, from tissue scaffolds for medicine to films for packaging.<br/>However the functioning span of starch-based materials is generally short, as starch is degraded quickly in the presence of water and, in human body, by amylases. Water sorption and swelling cause specific structural and physicochemical transformations in processed starches. These transformations can be modified by the addition of other components, for example plasticizers such as glycerol or nanofillers. Nanofillers have a high surface/volume ratio which creates stronger physico-chemical interactions with starch. This modifies the structure and consequently the properties. A better understanding of the role of nanofillers on the structural organization of starch could be critical in designing materials with controlled degradation rates and improved functionality.<br/>To investigate this question, native potato starch was mixed with glycerol and crystalline nanofillers of different nature (cellulose and chitin) in various concentrations. Materials were produced via twin-screw extrusion and their local structures characterized using various techniques, i.e. X-Rays Diffraction, CP-MAS NMR and Scanning Electron Microscopy. The macroscopic properties relevant to biodegradable materials, i.e. behavior during immersion in physiological media (swelling, degradability, diffusion) have been studied. A variation in structure and properties of nanocomposites is observed as fillers are introduced into the starch matrix; for example, increased swelling and modified enzymatic degradation are observed. The properties of the composites vary depending on the filler concentration and organization in the starch matrix. These effects are then linked to the local structure.

Nanofiller effect on structure-properties relationship of bio-sourced nanocomposites

2019 Spring National Meeting

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