Bioplastics from shellfish waste: Tuning the tensile and solubility properties of chitosan films

Authors: Orcutt, Kaydren; McCaffrey, Zachariah; Torres, Lennard; Wood, Delilah; Williams, Tina; Klamczynski, Artur; Kim, Jong Heon; Glenn, Gregory; Orts, William; Hart-Cooper, William

Submitted to: ACS Sustainable Resource Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/29/2025
Publication Date: 2/11/2025
Citation: Orcutt, K.B., McCaffrey, Z., Torres, L.F., Wood, D.F., Klamczynski, A.P., Kim, J., Glenn, G.M., Orts, W.J., Hart-Cooper, W.M., Williams, T.G. 2025. Bioplastics from shellfish waste: Tuning the tensile and solubility properties of chitosan films. ACS Sustainable Resource Management. https://doi.org/10.1021/acssusresmgt.4c00330.
DOI: https://doi.org/10.1021/acssusresmgt.4c00330

Interpretive Summary: Chitosan made from shellfish waste was used to make films by varying the composition - the molecular weight of the chitosan flake, the acid used to solubilize the flake, and the glycerin concentration. The effects of these composition changes as well as film treatments like neutralization on the properties of the films are reported here. The molecular weight of the film increased the strength of the film. When lactic acid was used to solubilize the chitosan flake, the breadth of change of the tensile properties increased. Neutralization led to stronger films that were insoluble in water. By altering the acid, molecular weight, and charge of the films, the intended use of the films will change. The films outlined in this paper fall into the categories of strong and water insoluble or flexible and water soluble.

Technical Abstract: Chitosans of varying molecular weights were solubilized with acids (lactic, acetic, and malic) and formed into films with glycerin added as a plasticizer, with additional treatments applied to tune the solubility and tensile properties of the films. Lactic acid solubilized chitosan made films that had a wider range of tensile properties when tuned by the glycerin concentration. Neutralizing the films led to tensile strength increasing from 16.48 to 58.95 MPa, with a loss in strain at break percent decreasing from 47.95% to 28.19%. A plasticizer bath after neutralization of a glycerin-containing film leads to an increase in tensile stress from 17.97 to 26.44 MPa. The neutralized films without a plasticizer bath show a loss from 54.94 to 42.42 MPa in 98% humidity, while the neutralized sample with plasticizer decreases from 41.10 to 8.11 MPa. Having mechanisms for tunability of the properties increases the applicability of chitosan films as sustainably produced replacements for petroleum-derived plastics in single-use packaging, textiles, and many other applications.