CELLULOSE AS A REINFORCEMENT IN BIODEGRADABLE STARCH FOAMS PACKAGING

Expanded polystyrene (EPS) is a widely used petroleum-based packaging. However, when inadequate disposed of, it causes environmental solid waste accumulation and microplastic formation. To mitigate the environmental impact caused by these wastes, new biodegradable materials with starch and vegetable fibers can be excellent alternatives to petroleum-derived plastics. Therefore, in addition to the development of expanded starch packaging, efforts have been made to improve mechanical properties by adding cellulose as a reinforcing filler material. The starch foam packaging was molded as trays on hot closed molds. It was produced using cassava starch varying the solid-to-water ratio (SWR) at 1:0.68, 1:0.72, 1:0.75, 1:0.79, 1:0.83, and 1:0.87, as well as different types of cellulose (microcrystalline and from soybean straw) as reinforcement. The different packaging was evaluated by moisture content, bulk density, color, and internal microstructure. The reduced SWR resulted in a wide variability of packaging structure. The moisture content of the trays ranged from 2-10%, with higher SWR leading to higher moisture content and requiring more time for foaming. Soybean straw cellulose has larger fibers than microcrystalline ones which requires a higher SWR for optimal performance as a reinforcing material. The higher SWR also resulted in lower bulk density, with the packaging filled with microcrystalline cellulose ranging from 0.256-0.420 cm3 g-1 and the packaging filled with soybean straw cellulose ranging from 0.412-0.437 cm3 g-1. The color of the trays showed slight variations, with L*>83, C*>7.2, and h>91 for all the packaging filled with microcrystalline, and cellulose from soybean straw showing L*>86, C*>8, and h>88.4. All trays presented a light shade and white color regardless of the type of cellulose and SWR. The use of different celluloses in the production of starch foam biodegradable packaging implies changes in the structure of the trays, but they are promising alternatives to petroleum-derived plastics.