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During the past two decades the use of bioplastics, as a suitable alternative to petroleum-based plastics, has attracted researchers' attention to a great extent. In this study, the whole wheat four and straw cellulose at different proportions were mixed with glycerol and bioplastics sheets were obtained by a press type molding machine. The mechanical properties of samples were examined on compositions prepared by whole wheat weight in three proportions of 70, 60 and 50% and the cellulose in three proportions 75, 70 and 65%. The tensile tests on the samples indicated that with lowering proportions of both four and cellulose, the modulus of elasticity and tensile strength of the bioplastics dropped as well. The maximum modulus of elasticity achieved for the four and cellulose compositions were 12.5, and 8.6 MPa, and the maximum tensile strengths were 878 and 202 kPa, respectively. The TGA tests indicated that the bioplastics prepared from whole wheat four showed higher temperatures of thermal degradation. The activation energies calculated for the four and cellulose bioplastics, as estimated by Arrhenius type equation, were 133.0 and 63.8 kJ/mol, respectively.

During the past two decades the use of lignocellouse fibers in reinforcing composites has attracted much research activities. In the present work, date palm fiber was used for production of composites compatible withliving environment. The fibers were pre-treated chemically to remove impurities. In order to verify and compare the effectiveness of the pretreatment methods, lignin, ash, moisture adsorption, diameter and tensile strength of the raw and treated fibers were considered in all determinations. Some chemical contents of the treated fibers were also estimated by FTIR method. The heating characteristics of the fibers were evaluated using simultaneous thermal analysis (SAT) technique. The treated fibers were mixed with HDPE by mass proportions of 10, 20 and 30% of the fibers in twotypes of fine and coarse sizes. Composite flower pots were prepared from the formulations by extrusion process. The mechanical properties of the composites including tensile strength, modulus of elasticity, strain, and impact strength were measured by standard ASTM methods. Statistical analysis of the data revealed that the treated fibers had smaller diameters containing lower levels of lignin and ash though having significantly higher tensile strength, heat resistance and moisture adsorption. The results also indicated that by increase in fibre size the tensile strength, modulus of elasticity and moisture adsorption of the composites are increased and their strain and impact resistance are decreased. The composites prepared using fine fibers showed higher tensile strength, modulus of elasticity and impact strength but their moisture adsorption and elongation were significantly lower.