Characterization of cottonseed protein isolate as a paper additive

Authors: Cheng, Huai; Villalpando, Andres; Easson, Michael; Dowd, Michael

Submitted to: International Journal of Polymer Analysis and Characterization
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/13/2017
Publication Date: 11/13/2017
Citation: Cheng, H.N., Villalpando, A., Easson, M.W., Dowd, M.K. 2017. Characterization of cottonseed protein isolate as a paper additive. International Journal of Polymer Analysis and Characterization. 22(8):699-708.

Interpretive Summary: Cottonseed protein is currently an abundant but underutilized natural resource, and it would be useful to seek new applications for it. In this work we have shown that surface treatment of paper with cottonseed protein enhanced dry and wet strength of paper. Concurrent addition of acid promoters enhanced dry paper strength, although the wet strength was unaffected. Through polymer characterization techniques, a better understanding was obtained of the interactions among paper fiber, cottonseed protein, and the acid promoters. These finding are useful because they suggest that cottonseed protein with or without additional acid promoters is a promising and eco-friendly alternative to the petroleum-based dry and wet strength resins in paper applications.

Technical Abstract: There is current interest in using agro-based biopolymers in industrial applications. Because cottonseed protein is abundantly available, it would be useful to explore its feasibility as a polymeric additive and possible substitute for petroleum-based materials. In this work we studied cottonseed protein isolate as a paper additive and observed its effects on the paper’s dry and wet strength. The tensile strength of paper was found to vary with the amount of the protein applied. By application of an 11% protein solution to the paper, the dry and wet strength increased by 33% and 16% compared with the paper by itself, respectively. The combined use of cottonseed protein and an acid (acetic, adipic, aspartic, and citric acids) to promote adhesion resulted in even greater dry paper strength but not in greater wet paper strength. Thermogravimetric analysis, infrared spectroscopy, and scanning electron microscopic studies suggested that the protein interacted with acid and that both components interacted with paper fibers to produce increased strength.