超音波探査法による表面処理炭酸カルシウム充填ポリプロピレンの内部構造評価
Acoustic Microscopy Evaluation of Polypropylene Filled with Surface Modified Calcium Carbonate
光石一太・川野道則・渋谷惇夫
Mizutani, Kazuta / Kawano, Michinori / Shibuya, Atsuo
The Dispersion behavior of a heterogeneous structure, which consists of an aggregate or agglomerate of particles and voids at the polymer-particle interface, has been studied by acoustic microscopy for polypropylene (PP) filled with surface modified calcium carbonate (CaCO3). In order to improve the affinity at the interface between PP and CaO3, mono alkyl dihydrogen phosphate of different carbon number (MAPn) were tested as modifiers for CaCO3, PP and CaCO3 were mixed on a two-roll mill and the films were prepared by compressing the mixed compound.
Using ultrasonic images, a binarization method was carried out to obtain the area fraction of the heterogeneous fracture in PP/CaCO3 composites. Next, the relationships between the area fraction of the heterogeneous structure and carbon number of MAPn, density, void at polymer-particle interface accompanying the elongation, mechanical properties (tensile elongation at break, modulus, yield stress) of PP/CaCO3 composites have been investigated. The area fraction of heterogeneous structure largely decreased with the modification of CaCO3 Surface. The dependence of heterogeneous structure on the value of MAPn was determined in this work. Although the tensile elongation at break and void at polymer-particle interface depended on the heterogeneous structure, the density, yield stress and the modulus of PP/CaO3 composites were nearly constant, irrespective of the area fraction of heterogeneous structure.
Key words: Acoustic microscopy / Polypropylene / Calcium carbonate / Modification