Bioplastic based on starch as the matrix and cellulose nanocrystals from rice straw as reinforcing filler were prepared in this study. The isolation of cellulose nanocrystal (CNC) followed a series of steps: delignification, sulfuric acid hydrolysis, and sonication. The process afforded short, rod-like CNCs with particle diameter ranging from 10 to 12 nm and crystallinity index of 76.1%. Fourier transform infrared analysis of the CNCs also confirmed absorption patterns typical of cellulose and the removal of silica. Bioplastic with different starch-to-CNC ratios were prepared by solution casting and evaporation method. Scanning electron micrographs of the films showed uniform dispersion of CNC in the starch matrix. Mechanical tests revealed that both tensile strength and modulus significantly increased with increasing CNC load while percent elongation decreased. The moisture uptake of the films reinforced with CNC also decreased an indication of improvement in water resistance. However, the thermal stability of the films decreased by the addition of CNC.

Room temperature dielectric and magnetic properties of BiFeO₃ samples, co-doped with magnetic Gd and non-magnetic Ti in place of Bi and Fe, respectively, were reported. The nominal compositions of Bi_0.9Gd_0.1Fe_1–xTi_xO₃ (x = 0.00-0.25) ceramics were synthesized by conventional solid state reaction technique. X-ray diffraction patterns revealed that the substitution of Fe by Ti induces a phase transition from rhombohedral to orthorhombic at x > 0.20. Morphological studies demonstrated that the average grain size was reduced from ∼1.5 μm to ∼200 nm with the increase in Ti content. Due to Ti substitution, the dielectric constant was stable over a wide range of high frequencies (30 kHz to 20 MHz) by suppressing the dispersion at low frequencies. The dielectric properties of the compounds are associated with their improved morphologies and reduced leakage current densities probably due to the lower concentration of oxygen vacancies in the compositions. Magnetic properties of Bi_0.9Gd_0.1Fe_1–xTi_xO₃ (x = 0.00-0.25) ceramics measured at room temperature were enhanced with Ti substitution up to 20% compared to that of pure BiFeO₃ and Ti undoped Bi_0.9Gd_0.1FeO₃ samples. The enhanced magnetic properties might be attributed to the substitution induced suppression of spiral spin structure of BiFeO₃. An asymmetric shifts both in the field and magnetization axes of magnetization versus magnetic field curves was observed. This indicates the presence of exchange bias effect in these compounds notably at room temperature.