Structure–property relationships of blended polysaccharide and protein biomaterials in ionic liquid

Abstract

Cellulose and silk blended biomaterial films were regenerated from ionic liquid solution and investigated to characterize and understand the effect of inter- and intra-molecular interactions upon the morphology and thermal properties. The blended films were dissolved in 1-allyl-3-methylimidazolium chloride ionic liquid, coagulated and regenerated with water. Various characterization techniques were implemented to characterize structural, morphological and thermal properties: FTIR, SEM, TGA, DSC and X-ray scattering. The results showed that the cellulose microcrystalline structure and β-sheets from the silk can be disrupted by inter- and intra-molecular hydrogen bonds forming intermediate semicrystalline or amorphous structures. The SEM showed morphological effects of such interactions that cause varying thermal degradation and glass transition temperature. The X-ray scattering confirms such findings at the molecular level, demonstrating that the cellulose microfibril diameter decreases as the silk content increases. It also shows that the β-sheets size increases as the cellulose content increases. These various techniques provide evidence that suggest the hydrogen bonds between the β-sheets and the glucose units in the cellulose chains control the thermal and structural properties of the blended films, changing the morphology and physicochemical properties.