Synthesis and characterization of a cassava starch (Manihot esculenta) and dried coffee pulp mixture to produce biofilms

Abstract

[EN] Currently, implementing strategies to minimize the impacts caused by solid waste is a priority that is integrated into environmental policies and development plans worldwide. Agro-industrial waste is one of many types of waste. This waste is an environmental problem, given that if it is not properly disposed of or reused, it can alter different natural resources, including soil, water and air, in addition to being a possible source of contamination and risk to human health. Notwithstanding, this waste has energetic potential which could be harnessed through different alternatives for its use and therefore reduce its environmental impact. This study presents an alternative strategy to manage the solid waste generated in the pulping stage of coffee processing, which entails incorporating dried pulp to make cassava starch biofilms which use glycerol and Polyvinyl alcohol (PVOH) as a plasticizer. Following a material synthesis process, its mechanical properties related to stress and impact strength were evaluated. Furthermore, a thermal characterization was performed with differential scanning calorimetry (DSC), a thermogravimetric analysis (TGA), and a dynamic-mechanical analysis (DMA). The prepared films contain 96.3% p/p of gelatinized cassava starch, 0.3% p/p of dry residue, 2.1% of glycerin, and 1.3% of PVOH. The result was a thermoplastic material that can be used to manufacture packaging materials given the values of its mechanical properties.