Cellulose esters: Synthesis for further formation of films with magnetite nanoparticles incorporated

This study investigated the homogeneous synthesis of cellulose acetate (CA) and propionate (CP) with varying degrees of substitution (DS) from sisal cellulose in a N, N-dimethylacetamide/lithium chloride (DMAc/LiCl) solvent system. These esters were used to prepare neat (CA_DSF/CP_DSF) and nanocomposite films (CA_DSFFe/CP_DSFFe) from prior synthesized magnetite nanoparticles (NPs, Fe₃O₄, 5.1 ± 0.5 nm). Among the CA and CP series, the composite CA_0.7FFe and the neat CP_0.7F films exhibited the highest modulus of elasticity, 2105 MPa and 2768 MPa, respectively, probably a consequence of the continuous fibrous structures present on the surface of these films. Microsphere formation on the film's surface was observed in scanning electron microscopy micrographs. This points to applications in the controlled release of targeted substances. The VSM analysis showed that the cellulosic matrices preserved the superparamagnetic characteristics of the NPs. This study suggested a reduced coupling effect between nanoparticles inside polymeric films due to magnetic saturation at low fields. CA_0.7FFe and CA_1.3FFe composite films reached a saturation magnetization (M_SAT) of 46 emu/g around 7 kOe field. Hosting magnetite nanoparticles in cellulose ester matrices may be an interesting way to develop new functional cellulose-based materials, which have the potential for diverse applications, including microelectromechanical systems and microsensors.