Controlling the structure and properties of semi-crystalline cellulose/silk-fibroin biocomposites by ionic liquid type and hydrogen peroxide concentration

• Published in: Carbohydrate polymer technologies and applications Vol. 3; p. 100193
• Main Authors: Love, Stacy A., Hu, Xiao, Salas-de la Cruz, David
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-06-2022; Elsevier
• Subjects: Cellulose II; Hydrogen peroxide; Imidazolium; Semi-crystallinity; β-sheet; Imidazolium; Cellulose II; β-sheet; Hydrogen peroxide; Semi-crystallinity
• ISSN: 2666-8939; 2666-8939
• DOI: 10.1016/j.carpta.2022.100193

•Solvent anion type effected changes onto protein amorphous/crystalline morphologies.•Solvent anion and coagulant concentration effected changes in the thermal stability of regenerated biocomposites.•Carbohydrate crystal size was positively correlated to H2O2 concentration upon fabrication and were calculated to have either a gradual or step transition increase in size depending upon fabrication solvent.
This work reports how to tune the semi-crystallinity of a blended microcrystalline cellulose/silk-fibroin biocomposite using ionic liquids and various coagulation agents. The morphological and thermal properties of a blended 1:1 polymeric system are studied as a function of polymer fabrication parameters. Ionic liquids, 1-ethyl-3-methylimidazolium acetate verses 1-ethyl-3-methylimidazolium chloride, are used as competing solvent types and six hydrogen peroxide solutions (1—25%) plus water are used as varying coagulation agents. Analysis of the results demonstrate that solvent anion type, Ac− verses Cl−, affects protein secondary structure formation, and that solvent anion type and the concentration of hydrogen peroxide changes morphology and thermal stability of the regenerated materials. Polymers dissolved in 1-ethyl-3-methylimidazolium acetate are less thermally stable than those dissolved in 1-ethyl-3-methylimidazolium chloride. Furthermore, carbohydrate microcrystal size is positively correlated to hydrogen peroxide concentration upon fabrication and is calculated to have either a gradual or step transition increase in microcrystal size depending upon the solvent's anion type.