Effect of Microfibrillated Cellulose Loading on Physical Properties of Starch/Polyvinyl Alcohol Composite Films

Abstract

The starch/polyvinyl alcohol (PVA)/microfibrillated cellulose (MFC) composite films were prepared using solution casting method after adding MFC into starch/PVA blend matrix. The effects of MFC content on the mechanical properties of starch/PVA composite films were investigated. As MFC content increases, the elongation at break and tensile strength increase firstly and then decrease. When the content of MFC is 2wt%, the tensile strength is 26.6 MPa and reaches the maximum. Through Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA), good dispersion of MFC in starch/PVA matrix at the loading of 2wt%, lower crystallinity of the starch/PVA/MFC films in comparison with starch/PVA blend and the effect of glass transition temperature increasing with MFC content from 0.5wt% to 4wt% can be found observed. And, incorporating MFC does not change the composition and crystal structure of the starch/PVA composite films. Thus, the reinforcing mechanism for the improvement of mechanical properties is attributed to the homogeneous dispersion of MFC with large aspect ratio, good compatibility and interfacial interactions between starch/PVA blend matrix and MFC.