超音波探査法を用いた炭酸カルシウム配合ポリプロピレン/エチレン酢酸ビニル共重合体の特性評価 [in Japanese] Acoustic Microscopy Evaluation of Polypropylene/Ethylene Vinyl Acetate Filled with Calcium Carbonate [in Japanese]
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The agglomerate of particles and voids at the polymer-particle interface and the heterogeneous structure, have been characterized by scanning acoustic microscopy for polypropylene (PP)/ethylene vinyl acetate polymer blends (EVA) filled with modified calcium carbonate (CaCO<sub>3</sub>). The relationships between the hoterogeneous structure and mechanical properties (tensile strength, elongation at break, impact strength) of the PP/EVA/CaCO<sub>3</sub> series were investigated.<br>Using ultrasonic images, the haterogeneous structure in the PP/EVA/CaCO<sub>3</sub> series was evaluated based on the binarization method. Polymer blends were prepared by mixing PP and EVA using a two-roll mill, then the PP/EVA mixture and various size CaCO<sub>3</sub> particulates were mixed on the same mill. Stearic acid was used as a modifier for CaCO<sub>3</sub>.<br>By adding 2wt% EVA to PP, the heterogeneous structure decreased to about one-seventh the value of the PP/CaCO<sub>3</sub> blend. Furthermore, the heterogeneous structure in the modified CaCO<sub>3</sub> series was about one-thirtieth that of the unmodified blends. The tensile elongation at break depends on the heterogeneous structure, irrespective of CaCO<sub>3</sub> size and EVA content. However, it is recognized that impact strength depends on the heterogeneous structure and particle size. The impact strength of PP/EVA filled with small CaCO<sub>3</sub> particulates was greater than that with larger CaCO<sub>3</sub> particulates for the same heterogeneous structure.
Seikei-Kakou 9(6), 434-441, 1997-06-20
The Japan Society of Polymer Processing