Submitted to: Carbohydrate Polymers
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/15/2014
Publication Date: 12/31/2014
Publication URL: http://handle.nal.usda.gov/10113/60537
Citation: Fanta, G.F., Selling, G.W., Felker, F.C., Kenar, J.A. 2015. Preparation and properties of films cast from mixtures of poly(vinyl alcohol) and submicron particles prepared from amylose-palmitic acid inclusion complexes. Carbohydrate Polymers. 121:420-427.
Interpretive Summary: Polyvinyl alcohol (PVA) is a water-soluble synthetic polymer widely used in papermaking, textiles, and a variety of coatings and films. Since it is relatively expensive and only slowly biodegradable, fillers and extenders have been investigated to reduce cost, increase biodegradability, and improve its physical properties. Starch-based nanoparticles can be prepared by using steam jet cooking to dissolve starch and form complexes with palmitic acid, a component of vegetable oil. Three methods were used to prepare cast PVA films containing up to 50% loading of starch nanoparticles made by the jet cooking method. The strength and stiffness of the films were only slightly worse than pure PVA films, but the toughness and ability to stretch before breaking were very similar to pure PVA. Microscopy revealed a uniform distribution of starch nanoparticles in the dried films. These results provide evidence that starch nanoparticles prepared by the commercially viable method of steam jet cooking to form starch complexes with palmitic acid are a potentially valuable technology for increasing the biodegradability and reducing the cost of PVA without significant loss of mechanical properties. Consumers of many types of products made with PVA will benefit from this research.
Technical Abstract: The use of starch in polymer composites for film production has been studied extensively for increasing biodegradability, improving film properties and reducing cost. Starch nanoparticles have received much attention, primarily those obtained by acid hydrolysis of starch granules. In this study, nanoparticles were prepared from amylose-sodium palmitate complexes both by rapidly cooling jet-cooked starch-palmitic acid mixtures and by acidifiying solutions of starch-sodium palmitate complexes. Films were cast containing poly(vinyl alcohol) (PVOH) with up to 50% starch nanoparticles. Tensile strength decreased and Young’s modulus increased with starch concentration, but percent elongations remained similar to controls regardless of preparation method or starch content. Microscopy showed particulate starch distribution in films made with rapidly cooled starch-palmitic acid nanoparticles but smooth, diffuse starch staining with acidified sodium palmitate complexes. The mild effects on tensile properties suggest that starch nanoparticles prepared from amylose-palmitic acid complexes provide a useful, commercially viable approach for PVOH film modification.