Rheological characterization of solutions and thin films made from amylose-hexadecylammonium chloride inclusion complexes and polyvinyl alcohol

Authors: Hay, William; Byars, Jeffrey; Fanta, George; Selling, Gordon

Submitted to: Carbohydrate Polymers
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/4/2017
Publication Date: 1/5/2017
Publication URL: http://handle.nal.usda.gov/10113/5632357
Citation: Hay, W.T., Fanta, G.F., Byars, J.A., Selling, G.W. 2017. Rheological characterization of solutions and thin films made from amylose-hexadecylammonium chloride inclusion complexes and polyvinyl alcohol. Carbohydrate Polymers. 161:140-148.

Interpretive Summary: This research determined the physical and processing characteristics of a value adding starch derivative which can be used to replace petroleum products. Developing technologies utilizing renewable materials to totally or partially replace materials which use petroleum feedstocks is of national importance. It has been shown that a starch derivative (Hex-Am), which is a combination of corn starch and hexadecylammonium chloride (derived from soybean oil), when added to polymers at levels of up to 60%, such as polyvinyl alcohol (produced form natural gas), provides improved physical properties. The processing characteristics of the starch derivative have to be known to fully utilize this renewable material in industrial production. The materials were determined to remain intact at high temperatures, and have limited water absorption. Knowing these properties, the value of barrier or protective products produced from Hex-Am would have a greater market value. This research provides confidence to polymer producers interested in using cost effective Hex-Am to replace a portion of petroleum based material in their polymers. By using Hex-Am in petroleum based products, improved properties will be obtained at a lower cost with a smaller carbon foot print. Corn and soybean producers and processors will benefit from this technology. In addition, traditional polymer producers will be able to provide a higher value product at lower cost, which will ultimately benefit the consumer.

Technical Abstract: The rheological properties of aqueous solutions and films made from blends of polyvinyl alcohol (PVOH) and amylose-hexadecylammonium chloride inclusion complexes (Hex-Am) were investigated to better understand the polymer interactions and processing parameters. Aqueous solutions of Hex-Am displayed typical non-Newtonian shear thinning characteristics, becoming highly viscous at 4.2% solids and forming a strong mechanical gel at 10% solids. Cationic Hex-Am was observed to have dramatically different rheological temperature response profiles from anionic amylose-sodium palmitate inclusion complexes, displaying precipitous increases in viscosity upon cooling of solutions from 95°C to 50°C. Aqueous solution blends of 1:1 PVOH/Hex-Am lack this precipitous increase in viscosity, indicating that PVOH reduces amylose-chain entanglement. Viscosities of Hex-Am and Hex-Am/PVOH blended solutions increase with addition of sodium hydroxide to a maximum at approximately pH 8. PVOH addition does not substantially alter the viscosity vs. pH response profile. Films cast from varying blends of Hex-Am and PVOH were thermostable to 200°C, and displayed decreasing storage modulus with increasing concentrations of PVOH in film blends. Films cast from Hex-Am/PVOH absorb water vapor at lower rates than their constitutive polymers.