Fabrication and properties of keratoses/polyvinyl alcohol blend films

Improved mechanical, antibacterial and UV barrier properties of catechol-functionalized chitosan/polyvinyl alcohol biodegradable composites for active food packaging

Bioinspired from adhesion behaviors of mussels, we first reported a new strategy to prepare catechol-functionalized chitosan (C-CS)/polyvinyl alcohol (PVA) composite films via a solution blending method in neutral aqueous solution for active food packaging. Compared with pure PVA film, the UV transmittance (at 280 nm) of C-CS/PVA composite films decreases by 67.6 % when C-CS content reaches 10 wt%. Still, all the C-CS/PVA composite films are transparent in the visible range. The maximal tensile strength and elongation at break of C-CS/PVA composite films can reach 45.2 MPa and 153 % respectively, which are 46.3 % and 25.4 % higher than those of pure PVA film. The incorporation of C-CS into PVA matrix increases the antibacterial properties significantly. The water resistance of C-CS/PVA composite films can not be significantly deteriorated by the appropriate amount of C-CS. Therefore, C-CS/PVA composite films show great potential in the field of active packaging due to its good mechanical, antibacterial and UV barrier properties.

Closing the Loop with Keratin-Rich Fibrous Materials

One of the agro-industry's side streams that is widely met is the-keratin rich fibrous material that is becoming a waste product without valorization. Its management as a waste is costly, as the incineration of this type of waste constitutes high environmental concern. Considering these facts, the keratin-rich waste can be considered as a treasure for the producers interested in the valorization of such slowly-biodegradable by-products. As keratin is a protein that needs harsh conditions for its degradation, and that in most of the cases its constitutive amino acids are destroyed, we review new extraction methods that are eco-friendly and cost-effective. The chemical and enzymatic extractions of keratin are compared and the optimization of the extraction conditions at the lab scale is considered. In this study, there are also considered the potential applications of the extracted keratin as well as the reuse of the by-products obtained during the extraction processes.

Poly(Vinyl Alcohol) Recent Contributions to Engineering and Medicine

Poly(vinyl alcohol) (PVA) is a thermoplastic synthetic polymer, which, unlike many synthetic polymers, is not obtained by polymerization, but by hydrolysis of poly(vinyl acetate) (PVAc). Due to the presence of hydroxylic groups, hydrophilic polymers such as PVA and its composites made mainly with biopolymers are used for producing hydrogels that possess interesting morphological and physico-mechanical features. PVA hydrogels and other PVA composites are studied in light of their numerous application for electrical film membranes for chemical separation, element and dye removal, adsorption of metal ions, fuel cells, and packaging. Aside from applications in the engineering field, PVA, like other synthetic polymers, has applications in medicine and biological areas and has become one of the principal objectives of the researchers in the polymer domain. The review presents a few recent applications of PVA composites and contributions related to tissue engineering (repair and regeneration), drug carriers, and wound healing.