Poly(vinyl alcohol) composite films with high percent elongation prepared from amylose-fatty ammonium salt inclusion complexes

Authors: Fanta, George; Felker, Frederick; Selling, Gordon; Hay, William; Biswas, Atanu

Submitted to: Journal of Applied Polymer Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/22/2016
Publication Date: 7/13/2016
Citation: Fanta, G.F., Felker, F.C., Selling, G.W., Hay, W.T., Biswas, A. 2016. Poly(vinyl alcohol) composite films with high percent elongation prepared from amylose-fatty ammonium salt inclusion complexes. Journal of Applied Polymer Science. 133(42).

Interpretive Summary: Starch is widely used as a component in biodegradable plastics and films because it is inexpensive, annually renewable, and biodegrades rapidly. However, films prepared from pure starch do not have the strength, flexibility, and ease of processing required for many applications. Although the synthetic plastic poly(vinyl alcohol) (PVOH) has been blended with starch to overcome these disadvantages, PVOH is more expensive than starch, has a lower rate of biodegradation, and is not biobased. For practical applications, it is therefore necessary to maximize the amount of starch-based materials in these mixtures while still retaining the desirable properties of PVOH. In this study, we dissolved starch by the economical industrial process of steam jet cooking and used it to prepare complexes with inexpensive fatty amine salts derived from soybean oil. These starch-fatty amine salt complexes are soluble in water and can be blended with PVOH to prepare films with good physical properties, especially an increased ability of the film to stretch without breaking. Films prepared from PVOH and the starch-fatty amine salt complexes are also more resistant to the penetration of water than films prepared from pure PVOH. In addition to the low cost and rapid biodegradability of the starch-based component, the unique physical properties of these films also provide marketable advantages.

Technical Abstract: Amylose inclusion complexes prepared from cationic fatty ammonium salts and jet-cooked high amylose starch were combined with poly(vinyl alcohol) (PVOH) to form glycerol-plasticized films. Their tensile properties were compared with similar films prepared previously with analogous anionic fatty acid salt complexes. Cationic complex films had higher % elongations than those with anionic complexes, although tensile strength and Young’s modulus were somewhat lower. Elongation was significantly higher than PVOH films for 20% to 40% incorporation of cationic complex. Surface hydrophobicity (contact angle) was significantly higher than PVOH, but to a lesser extent than anionic complex films. Microscopy showed no phase separation or phase inversion, unlike that observed with films prepared from amylose fatty acid complexes, suggesting more intimate mixing due to ionic interactions between cationic ammonium salt complexes and hydroxyl groups of PVOH. The high elongations of these films are marketable advantages, along with the lower cost and increased biodegradability.