Clay Nanocomposites in Biodegradable Starch Plastics

Abstract

In recent times biopolymers, polymers synthesised by nature such as starch and polysaccharides, have been investigated as environmentally friendly alternatives to traditional oil-derived plastics. However, these natural polymers do not demonstrate the same material properties as traditional plastics, limiting potential applications of the technology. This study examines the material properties of starch-based polymers when nanoscale clay particles are dispersed into the starch matrix in order to improve the basic material properties of starch plastics.Three forms of starch were utilised in this investigation:. Wheaten corn flour . a native starch.. Gelose-80 . a highly amorphous starch.. A939 . hydroxypropylated Gelose-80.The starches were blended with two different nanoscale clays, Cloisite 30B and Cloisite 15A. Extrusion was used to process the starch thermoplastics, with the high viscosity of starch proving to be a constant problem.The mechanical, thermal and structural properties of the resultant blends were investigated using tensile tests, differential scanning calorimetry and x-ray diffraction. The data was collected and analysed.The nanoscale clays were found to enhance the properties of wheat starch, but degrade those of A939. The clays did not nanodispersed through the material, as determined by x-ray diffraction, but the effect of these additives was significant.