Development of eco-friendly starch/microcrystalline cellulose biofilms with improved optical, dielectric and mechanical performance using layered double hydroxide as a reinforcing material

Abstract

In this study, nanocomposite films consisting of potato starch (PS), layered double hydroxide (LDH), and microcrystalline cellulose (MCC) were synthesized using the solution casting method. The MCC particles were used to stabilize the dispersion of LDH during film preparation. The study investigated the effect of LDH particles on the optical, electrical, dielectric, mechanical, and barrier properties of PS/MCC films. The X-ray diffraction and scanning electron microscopy analysis confirmed that the PS/MCC/LDH ternary films had a partially intercalated and partially exfoliated structure. FTIR and Raman spectroscopy analysis revealed the formation of new hydrogen bonds between PS hydroxyl groups and nanoparticles. The direct optical band gap decreased from 5.80 to 5.44 eV with increasing LDH content. The refractive index, optical conductivity and optical dielectric constant all improved with increasing LDH content. The presence of MCC and LDH had little effect on the optical clarity of the starch-based films. The improving of dielectric properties was demonstrated by decreasing the dielectric loss tangent with increasing LDH content. The addition of 1%, 3%, and 5% by weight of LDH to the pure starch PS film resulted in significant improvements in tensile strength and tensile modulus of the ternary nanocomposites. In addition, the water solubility of the nanocomposites decreased with the addition of LDH. The principal component analysis results confirmed the positive effect of higher biopolymer content on these properties. The results of the study confirm that PS/MCC/LDH nanocomposites films can be used in optical and electronic applications.