|SOUSA, A - The University Of Porto|
|SOUZA, H - The University Of Porto|
|GONCALVES, M - The University Of Porto|
Submitted to: International Journal of Biological Macromolecules
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/19/2015
Publication Date: 5/1/2015
Publication URL: http://handle.nal.usda.gov/10113/61019
Citation: Sousa, A.M., Souza, H.K., Liu, L.S., Goncalves, M.P. 2015. Alternative plasticizers for the production of thermo-compressed agar films. International Journal of Biological Macromolecules. 76:138-145. DOI: 10.1016/j.ijbiomac.2015.02.030..
Interpretive Summary: Agar, a naturally occurring biopolymer extracted from red seaweed, was evaluated as a low-cost raw material for the development of bioplastics. However, the agar-derived plastics were brittle and did not exhibit strength and elasticity. In this research, agar films were prepared using compression-heating under high temperature and pressure in the presence of a non-toxic salt, choline chloride, as a plasticizer added to improve their properties. The resultant agar films possess improved flexibility, strength and elasticity providing a new platform for further development of packaging materials from agar.
Technical Abstract: One percent agar (% wt) was dissolved in the deep eutectic solvent (DES), (2-hydroxyethyl) trimethylammonium chloride/urea at a 1:2 molar ratio, and successfully Electrospun into nanofibers. An existing electrospinning set-up, operated at 50 deg C, was adapted for use with an ethanol bath to collect the fibers. Agar-in-DES showed improved viscoelasticity and hence, spinnability, when compared to agar-in-water, if working above the temperature of the sol-gel transition. The addition of polyvinyl alcohol (PVA; 5% wt) further improved agar-in-DES spinnability; i.e., the viscosity increased and the gelation temperature decreased. The Electrospun composite fibers were mostly in the submicron range in size. Processing agar fibers at the submicron scale could be quite useful since the fibers afford performance and properties not seen in the bulk materials. DESs can be sustainable tools to this end.