Brazil. Scientists at the University of Rio Grande do Sul recently investigated the effect of polylactic acid coating on the mechanical and physical properties of thermoplastic starch foams from potato starch.
Single-use packaging is widely used in the food industry and is mainly made of expanded polystyrene (EPS). These packages are discarded immediately after use and generate large amounts of waste. Thermoplastic starch foams (TPS) can be used in these situations because the starch comes from renewable sources and is biodegradable. Despite these advantages, TPS has a high affinity with water, making it difficult to apply as packaging.
Such a problem can be solved by coating the TPS foam with a hydrophobic material that prevents contact of water with starch. In this work, polylactic acid (PLA) was used as a coating due to its hydrophobicity and also because it is a biodegradable material.
Three coating concentrations were evaluated: 2%, 4% pla and 6% w/v. The foams were made from potato starch, water and glycerol (62/5/33% m/m). PLA coatings increased the density, tensile strength and impact resistance of the foams. TPS foams with 6% w/v PLA coating exhibited an excellent 225% reduction in water absorption compared to TPS foam.
Source: www.sciencedirect.co
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