Biodegradable Cassava Starch Based Foams Using Rice Husk Waste as Macro Filler

Abstract

Among the packages based on petroleum polymers, the use of the expanded polystyrene (EPS) which presents low production costs, low density, high resistance to humidity and dimensional stability, stands out. However, the improper disposal and difficulty of recycling them, together with their non-biodegradability can result in serious environmental problems. Knowing that there is no way to inhibit the population from using this material, the present study aimed to produce ecofriendly foams based on cassava starch and rice husk (RH). When compared to EPS, materials developed with biopolymers have lower flexibility and higher water sensitivity. The addition of rice husk improved the mechanical properties and reduced density and water capacity absorption in comparison to foams made using only starch. Foams were obtained by a thermopressing process, and the influence of different RH proportions (0, 20, 40, and 60% (w/w)) was investigated. The greater the RH amount, the higher the density and the lower the water absorption capacity (WAC). The maximum tensile stress and tensile strain were negatively influenced by the addition of 60% (w/w) RH. Differently from the maximum flexural stress that was positively influenced. Additionally, sorption isotherms showed that the samples with 40 and 60% RH adsorbed less water when compared to the foam without the filler. The formulation with 60% RH was chosen to storage cherry tomatoes due to its higher maximum flexural stress and lower WAC, being considered a promising material.