Thesis (M.Sc.)--Chulalongkorn University, 2004

The blends of LDPE and Ethylene-Octene copolymer (EOC) were prepared using tandem extruder. The weight fraction of EOC in the blends was varied in the range of 5-25%. Two sets of the blended foams with talc 0.5% and 1.0% was investigated. Regardless of the amount of talc content in the blends, the mechanical properties of blends such as tensile strength, elongation, compression strength and impact strength show a steady increase with higher EOC content, except at 20% of EOC content. Increase in the amount of talc from 0.5% to 1.0% also leads to the increase in cell number and density which leads to the increase in mechanical properties of the blended foams. At the talc content 1.0% in the blends, rheological properties of blends with 15-25% of EOC were determined. The shear and elongation behavior were analyzed in terms of elastomer amount and effect of die geometry on L/D ratios. It was found that an increasing amount of EOC in the matrix, the real shear stress and the viscosity were increased at the same shear rate. On the other hand, the tensile stress on the elongation rate exhibited increasing non-linear manner. It was found that the blend with 20% EOC content has lower tensile stress than those with 15% and 25% of EOC. This might be due to incompatibility of the blend system at 20% EOC content.