Physical Properties of Thermoplastic Cornstarch/Hibiscus sabdariffa Fiber Obtained by Evaporation Casting

Abstract

AbstractHibiscus sabdariffa is a typical ingredient in a popular Mexican beverage, and a lot of waste is produced as a result. The fibers obtained from Hibiscus sabdariffa waste can be used as reinforcement in a natural composite. This research evaluates the influence and effect of different properties of fiber incorporated into a cornstarch matrix. The mechanical and thermomechanical performance is evaluated using tensile measurements and dynamic mechanical analysis. Thermal stability is analyzed by thermogravimetric analysis. The micrographics show a good incorporation of the bioreinforcement into the polymer matrix. The tensile measurements show that the fiber can be related to a slight decrease in Young´s modulus. The dynamic mechanical analysis results show that the composite with 4 wt% of reinforcement has a higher storage modulus (1139 MPa at 50 °C) than the starch matrix (854 MPa at −50 °C). According to the thermal stability of the composites is displaced to lower temperatures, which can suggest an effect of biodegradation acquired with the progressive addition of the biofibers. As a result, the composites obtained have been shown to be sustainable and friendly to the environment, and the films can offer an advantage for packaging‐type bags for foods.