Improved hydroxypropyl methylcellulose (HPMC) films through incorporation of amylose-sodium palmitate inclusion complexes

Authors: Hay, William; Fanta, George; Peterson, Steven - Steve; Thomas, Andrew - Aj; Utt, Kelly; WALSH, KATHLEEN - University Of Illinois; Boddu, Veera; Selling, Gordon

Submitted to: Carbohydrate Polymers
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/28/2018
Publication Date: 2/5/2018
Citation: Hay, W.T., Fanta, G.F., Peterson, S.C., Thomas, A.J., Utt, K.D., Walsh, K.A., Boddu, V.M., Selling, G.W. 2018. Improved hydroxypropyl methylcellulose (HPMC) films through incorporation of amylose-sodium palmitate inclusion complexes. Carbohydrate Polymers. 188:76-84.

Interpretive Summary: We developed a new technique for producing higher value films using a modified starch. Normally, when standard starch is added to polymeric materials the resulting films are weak and readily allow gases to pass through them; the latter results in food spoilage. Corn starch is an abundant bio-based material which is often used to increase the biodegradability of polymer products. By treating corn starch with a vegetable oil derivative, sodium palmitate, at temperatures above the boiling point of water, a starch complex is formed. The resulting polymer blended films (starch complex + hydroxypropyl methylcellulose) are better gas barriers, making it more suitable as a food coating or for use in food packaging. The blended films are more stable at high temperatures, increasing their utility in foods and baked goods. Finally, the polymer blend films are less soluble at neutral and acidic solutions, which could be utilized for new pharmaceutical coatings. This manuscript outlines a new and novel method for improving polymer products through the incorporation of starch complexes produced from corn. The technology will be useful to all participants in the corn value chain. In addition, companies involved with cellulose production and its conversion will also benefit as the improved polymer blends will offer new uses for this polymer.

Technical Abstract: Polymer film blends of hydroxypropyl methylcellulose (HPMC) and amylose-sodium palmitate inclusion complexes (Na-Palm) were produced with no plasticizer, and were observed to have improved physical and gas barrier properties as compared with pure HPMC. The crystalline amylose helices incorporating the hydrophobic sodium palmitate ligand decreased the water vapor permeability of a 50/50% blended film of HPMC/Na-Palm by 40% and decreased oxygen permeability by 96%. The incorporation of 25% Na-Palm into HPMC films resulted in improved elongation, Young’s modulus and toughness. Addition of the amylose-complexes produced relatively smooth, high clarity films which had reduced solubility in neutral and acidic solutions. Increasing concentrations of Na-Palm increased film thermal resilience and increased storage modulus at high temperatures. The heat deflection temperature of the films also increased with increasing concentrations of amylose-complex; HPMC/Na-Palm film blends with >50% Na-Palm displayed almost no material deformation at 250°C.