| dc.description | The growing concern with the amount of plastic materials found in
the oceans makes it necessary to develop biodegradable materials that have low
toxicity to marine animals and humans, but at the same time are resistant to the
actions of microorganisms such as fungi or bacteria. On the other hand, agricultural
waste rich in inorganic materials (such as silica) is often discarded, while it could
be reused as a source of raw material. Considering these points, sodium silicate
solution extracted from sugarcane waste ash was utilized to prepare biodegradable
bioplastics based on corn starch and potato starch. The starch-based bioplastics
were produced by casting and characterized by several physical-chemical
techniques evaluating tensile strength, elongation at break, color analyses,
transparency, opacity, moisture, and biodegradation assay. Bioplastics prepared
with corn starch presented better physical, mechanical, and thermal properties and
optical quality than bioplastics based on potato starch. The samples called CS3 and
PS3, with 5.0% glycerol, were the most resistant to tensile strengths of 0.73 and
0.36 MPa, respectively. On the other hand, the highest elongation at break values were found for the samples with 7.5% glycerol
(CS9, 52.90% and PS9, 49.33%). Corn starch-based bioplastics were more thermally resistant (CS3, 152.86 ??C and CS9, 135.20 ??C)
when compared to potato starch-based bioplastics (PS3, 140.39 ??C and PS9, 127.57 ??C). In general, the addition of sodium silicate
solution improved the mechanical and thermal properties of both types of bioplastics. The potato starch-based bioplastics were
biodegraded in 5 days, while those made from corn starch took almost 40 days. The inclusion of sodium silicate inhibited fungal
growth for both corn starch and potato starch bioplastics. The results suggest that sodium silicate solution obtained from renewable
sources can be incorporated into starch-based bioplastics for production of biodegradable packaging with antifungal activity. | |
