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Water‐repellent films from corn protein and tomato cutin
Author(s) -
Hood Christine,
Laredo Thamara,
Marangoni Alejandro G.,
Pensini Erica
Publication year - 2021
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.50831
Subject(s) - cutin , contact angle , attenuated total reflection , fourier transform infrared spectroscopy , materials science , chemistry , chemical engineering , polymer chemistry , infrared spectroscopy , organic chemistry , composite material , biochemistry , engineering
Flexible and hydrophobic biobased films were obtained using zein esterified with methanol and para ‐toluene ( p ‐toluene) sulfonic acid, cutin from tomato peels and ethanol. Esterification was confirmed by proton nuclear magnetic resonance and attenuated total reflectance–Fourier transform infrared spectroscopy (ATR‐FTIR). Non‐modified zein films were brittle and hydrophilic. ATR‐FTIR demonstrated that zein esterification increased zein hydrophobicity. Without cutin, esterified zein films were hydrophobic but brittle. Addition of cutin yielded films that were flexible and hydrophobic, as demonstrated by contact angle measurements. Principal component analysis (PCA) of ATR‐FTIR data showed that intensities at 3195 cm −1 and 3490 cm −1 were correlated to the relative hydrophobicity of zein films. PCA also showed that films of esterified zein and cutin were more hydrophobic than their counterparts (non‐modified zein without cutin). Optical and scanning electron microscopy demonstrated that esterified zein was compatible with cutin and yielded cohesive films, which did not fracture upon bending.