Properties of agar/cassava starch films manufactured by hot-melt extrusion method

Abstract

Agar/cassava starch bioplastic film preparation using the extrusion technique was carried out to obtain a continuous production method that is more applicable to industrial production practices. Various ratios (w/w) of agar-and-cassava-starch blends were used in the bioplastic film formulations with glycerol as the plasticizer. All the ingredients were compounded using a single-screw extruder at 110°C. The extrudates were dried and chopped into bioplastic resin pellets, followed by hot compression into a film sheet. The bioplastic film samples were tested for their mechanical properties, water sensitivity, biodegradability and chemical structures. In general, the amount of agar in film formulations was prominently associated with superior mechanical properties, such as the tensile strength, elongation at break and water resistance of the samples. On the other hand, cassava starch contributed to faster film degradation in soil and water. These results, in general, could be explained by the inherent properties of each biopolymer constituent and the number of hydroxyl groups (OH) in the chemical structure of each film sample, which was observed by Fourier transform infrared spectroscopy. This investigation showed that agar/cassava starch bioplastic production using the hot-melt extrusion method was promising for further implementation on a commercial production scale.