Biodegradable foams based on starch, polyvinyl alcohol, chitosan and sugarcane fibers obtained by extrusion

Abstract

Biodegradable foams made from cassava starch, polyvinyl alcohol (PVA), sugarcane bagasse fibers and chitosan were obtained by extrusion. The composites were prepared with formulations determined by a constrained ternary mixtures experimental design, using as variables: (X 1 ) starch / PVA (100 -70%), (X 2 ) chitosan (0 -2%) and (X 3 ) fibers from sugar cane (0 -28%). The effects of varying proportions of these three components on foam properties were studied, as well the relationship between their properties and foam microstructure. The addition of starch/PVA in high proportions increased the expansion index and mechanical resistance of studied foams. Fibers addition improved the expansion and mechanical properties of the foams.There was a trend of red and yellow colors when the composites were produced with the highest proportions of fibers and chitosan, respectively. All the formulations were resistant to moisture content increase until 75% relative humidity of storage.

Effect of PVA and PDE on selected structural characteristics of extrusion-cooked starch foams

“…Measurements for each foam type were performed with 10 repetitions. From the obtained stress-strain curves the following structural parameters were determined: the ultimate compression force (N) as the force causing sample fracture, and the Young modulus (MPa) as the deformation resistance of the foam [42][43][44] .…”

A review: Starch-based composite foams

“…Sugarcane bagasse, cotton linter, hemp, cellulose, and wheat bran were mixed and extruded with cassava starch, potato starch and wheat flour [19,20,22,26,27,67].…”

Characterisation of Cassava Bagasse and Composites Prepared by Blending with Low-Density Polyethylene

“…According to Akil et al (2011), vegetable fibres include bast fibres (or sclerenchyma), leaf or hard fibres, seeds, fruit, wood, cereal straw, and other grass fibres, most of which are composed of cellulose, hemicelluloses, lignin, waxes, and several water-soluble compounds, where cellulose, hemicelluloses, and lignin are the major constituents. Vegetable fibres have been used as a reinforcement of plastics and composites due to advantages such as lower density and good mechanical properties, as well as their economical and environmental advantages (Schmidt and Laurindo 2010;Debiagi et al 2011). If one is to consider cassava bagasse as potential polymer filler, it is important to know about its composition because, apart from containing cellulose and hemicelluloses, it also contains a high amount of starch, a natural polymer that has a high polarity due to the presence of large amounts of hydroxyls in its macromolecules, which interact with lignocellulosic fibres, resulting in improved mechanical properties (Corradini et al 2008).…”