Elongation properties of extruded cornstarch were improved by blending with glycerol. Further blending of starch-glycerol with polyvinyl alcohol (PVOH) resulted in significant improvements in both tensile strength (TS) and elongation at break. Samples of starch-glycerol without PVOH equilibrated at 50% relative humidity had a TS of 1.8 MPa and elongation of 113%, whereas those containing PVOH had a TS and elongation of 4 MPa and 150%, respectively. Dynamic mechanical analysis (DMA) of starch-glycerol-PVOH blends showed that decreases in glass transition temperatures (T-g values) were proportional to glycerol content. Scanning electron microscopy (SEM) of fractured surfaces revealed numerous cracks in starch-glycerol (80:20) samples. Cracks were absent in starch-glycerol (70:30) samples. In both blends, many starch granules were exposed at the surface. No exposed starch granules were visible in blends with added PVOH. Starch-glycerol samples incubated in compost lost up to 70% of their dry weight within 22 days. Addition of PVOH lowered both the rate and extent of biodegradation.
|Autori:||Mao, L; IMAM S., H; Gordon, S; Cinelli, P; Chiellini, Emo|
|Titolo:||Extruded Cornstarch-Glycerol-Polyvinyl Alchohol Blends: Mechanical Properties, Morphology and Biodegradability|
|Anno del prodotto:||2002|
|Digital Object Identifier (DOI):||10.1023/A:1015201928153|
|Appare nelle tipologie:||1.1 Articolo in rivista|