Rice bran-based bioplastics: Effects of the mixing temperature on starch plastification and final properties

Abstract

The agro-food industry produces huge amounts of wastes and by-products with high levels of carbohydrates and proteins, basic food groups that, properly treated, can be employed for the development of bioplastics. These high added-value products represent an alternative to traditional polymers. In this research work, rice bran was mixed with glycerol and water obtaining homogeneous blends which then are processed into bioplastics via injection moulding. The mixing temperature aids starch plastification and thus, affects the properties of the final specimens. In this way, the mechanical characterization revealed improvements for the highest temperature (110 °C) used which, at the same time, exhibited poor physical integrity during water immersion. Although the mechanical properties of the dried system obtained at 80 °C are slightly inferior to those obtained for the non-dried 110 °C system, these specimens are considered more adequate since they exhibited higher physical integrity and, consequently, better operating conditions.

Keywords: Bioplastics; Injection-moulding; Starches.