Structure and physical properties of zein/pluronic f127 composite films.
Triblock copolymer Pluronic F127 has been used to form composites with zein, a corn protein and coproduct of the bioethanol industry, to alleviate its natural brittleness. At low F127 loadings (0-35%), the plasticizing effect was dominant, and the elongation at break of zein composite film containing 35% F127 was about 8-fold higher than that of the zein film with 10% F127. At high F127 loadings (50-100%), a large number of lamellae crystals were formed in the film matrix as verified by a combination of differential scanning calorimetry (DSC), atomic force microscopy (AFM), and small-angle X-ray scattering (SAXS). The F127 crystallization surpassed its plasticizing effect, resulting in an increased brittleness of zein film with the further increase of F127 loading. Compared with the flat-on lamellae of pure F127, F127 chains folded into branch-like lamellar structures in the zein composite film containing 50% F127 due to the confinement of amorphous zein. Besides, the crystals in zein films were composed of extended chain integral folding (IF = 0) and once-folded chain (IF = 1) polyethylene oxide (PEO) crystals, and the portion of once-folded chain (IF = 1) PEO crystals increased with F127 loading. Thus, through investigation of the competition of plasticizing effect and crystal formation under different F127 loadings, the optimized F127 loading in zein/F127 composite film with a good overall performance was determined to be at around 35%.
Department of Food Science, Rutgers University, 65 Dudley Road, New Brunswick, NJ 08901-8520, USA.
Ji
J
Li
Yunqi
Y
Li
Tung-Ching
TC
Lee
Qingrong
Q
Huang
D002152:Calorimetry, Differential Scanning; D018625:Microscopy, Atomic Force; D020442:Poloxamer / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D013499:Surface Properties; D015028:Zein / Q000737:chemistry*
D011108:Polymers; D020442:Poloxamer; D015028:Zein