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Mixture design to develop biodegradable sheets with high levels of starch and polyvinyl alcohol
Author(s) -
Zanela Juliano,
Shirai Marianne Ayumi,
Reis Mônica Oliveira,
Mali Suzana,
Grossmann Maria Victória Eiras,
Yamashita Fabio
Publication year - 2015
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/star.201500094
Subject(s) - polyvinyl alcohol , materials science , crystallinity , ultimate tensile strength , elongation , extrusion , composite material , plastics extrusion , glycerol , starch , fourier transform infrared spectroscopy , scanning electron microscope , chemical engineering , chemistry , food science , organic chemistry , engineering
A mixture design was used to analyse the effects of polyvinyl alcohol (PVA) on glycerol‐plasticised cassava starch sheets obtained by flat extrusion from a twin‐screw extruder. PVA was the main component that improved the properties of the sheets, and glycerol presented the opposite effect. The properties ranging: tensile strength (0.22–1.5 MPa), Young's modulus (0.45–7.29 MPa), elongation at break (59–111%), puncture resistance (10–107 N/mm), puncture elongation (5.64–10.13 mm), crystallinity index (17–21%) and water vapour permeability (3.39–7.40 × 10 −5 g m −1 day −1 kPa −1 ) for the sheets. Scanning electron microscopy showed good compatibility between the components of the blend because the resultant materials were continuous and cohesive and did not exhibit phase separation. The sheets were not significantly different from others, based on XRD and FTIR analyses, consistent with the literature. PVA was able to improve the mechanical and barrier properties of starch‐based sheets.