Preparation and Physicochemical Properties of Blend Films of Feather Keratin and Poly(vinyl alcohol) Compatibilized by Tris(hydroxymethyl)aminomethane

Abstract

Blend films of feather keratin (FK) and synthetic poly(vinyl alcohol) (PVA) that were compatibilized by tris(hydroxymethyl)aminomethane (Tris) were successfully prepared by a solution-casting method. The scanning electron microscopy (SEM) results showed that a phase separation occurred in the FK/PVA/Tris blended system. Analysis by Fourier transform infrared spectroscopy indicated that the main interactions between the three components were hydrogen bonds. In addition, X-ray diffraction analysis showed that the FK/PVA/Tris blend films were partially crystalline. The barrier properties, mechanical properties, and contact angles of the FK/PVA/Tris films were investigated to determine the effects of the PVA and Tris concentrations. More specifically, upon increasing the PVA content, the elongation at break, the hydrophilicity, and the oxygen barrier properties were enhanced. However, at a constant PVA content, an increase in the Tris content caused the oxygen permeability and the contact angle to decrease, while the tensile strength, elongation at break, and oxygen barrier properties were enhanced. These results indicated that the mechanical properties and gas resistance of the FK/PVA/Tris blend films could be successfully improved using the method described herein, confirming that this route provided a convenient and promising means to prepare FK plastics for practical applications.

Plasticization of Cottonseed Protein/Polyvinyl Alcohol Blend Films

“…in the presence of a plasticizer. A previous study has reported a similar result for Tris-plasticized FK/PVA blend films [25]. In addition, the collapse point of the 20%-TEA and 20%-PEG water droplets occurred after approximately 30 s, which was 7 s later than for 20%-Gly and 20%-EG.…”

“…This difference in behavior between the blend film and plasticized blend films indicates that the moisture sensitivity increased in the presence of a plasticizer. A previous study has reported a similar result for Tris-plasticized FK/PVA blend films [25]. in the presence of a plasticizer.…”

“…More specifically, the pure PVA powder exhibited two characteristic crystalline peaks at 19.6 • and 22.5 • , which were attributed to the 101 and 002 crystal planes, respectively [34,39]. Furthermore, a diffraction peak was also observed at 40.7 • , indicating that PVA is a semi-crystalline polymer, whose crystallinity is due to strong intermolecular interactions between the PVA polymer networks [25]. In addition, the pure CP powder exhibited a broad diffraction peak at 20.5 • .…”

Keratin Associations with Synthetic, Biosynthetic and Natural Polymers: An Extensive Review

“…They observed that by increasing the PVA content, the elongation at break, hydrophilicity and oxygen barrier properties were enhanced, while the elastic modulus and water vapour barrier properties decreased. On the other hand, increasing the amount of Tris increased the tensile strength, elongation at break and oxygen barrier properties, while the contact angle decreased, with Tris playing the role of plasticizer in the blend [167]. 7.1.7.…”

“…They observed that the crosslinking with DAS decreased the films crystallinity and their total water soluble mass below 35% at 37 • C. Furthermore, they applied the films as vehicles to release Rhodamine B dye (as a model drug) and observed that the release rates decreased proportionally with increases in the amount of DAS, allowing the controlled release in function of the crosslinking [166]. Furthermore, Chen et al [167] prepared similar chicken feather keratin/PVOH blend films compatibilized by tris(hydroxymethyl) aminomethane (Tris) via solution casting. The authors reported the formation of a partially crystalline phase separated system with the components mainly interacting via H-bonding.…”