ABSTRACT:Montmorillonite was organically modified with distearyldimethylammonium chloride. This organically modified clay (OMON) and poly( e-caprolactone) (PCL) were solvent-cast blended with chloroform, and the structure and properties of the resulting PCL-clay blends were investigated. From isothermal crystallization experiments, it was found that a small amount of OMON in the blend accelerated the crystallization of PCL, whereas a large amount of the organophilic clay delayed it. From smalland wide-angle X-ray scattering measurements, it was found that the silicate layers forming the clay could not be dispersed individually in the PCL blends. In other words, the clay seemed to exist as the tactoids consisting of some silicate layers. These tactoids formed a remarkable geometric structure; that is, their surface planes lay almost parallel to the blend film surface. Furthermore, the tactoids were stacked with insertion of PCL lamellae in the film-thickness direction. Preferred orientation of the PCL crystallites was induced by the presence of the clay. During the drawing process of the blends, fibrillation took place with formation of planelike voids developed on the plane parallel to the film surface. From dynamic viscoelastic measurements, it was shown that intercalation of PCL chains into the layered silicates did not take place in the blends prepared by the solvent-cast method used in this work.
Montmorillonite (MON) was solvent-cast blended with poly(vinyl alcohol) (PVA) and poly(ethylene oxide) (PEO) using water as cosolvent. The structure and properties of the blend films have been investigated. From small-and wide-angle Xray scattering measurements of the blends, the silicate layers of MON are found to be well dispersed individually in the PVA-MON blends, while the silicate layers in PEO-MON blends are found to exist in the form of a large clay tactoid. Furthermore, for both blends, it is found that the silicate layers are parallel to the film surface of the blends, and that preferred orientation of polymer crystallites is induced by the presence of MON. The effects of the MON content on the thermal behavior of the PVA-and PEO-MON blends have been studied with a differential scanning calorimeter. Furthermore, the effects of geometry of the silicate layers on dynamic behavior of the blends have been studied.
A new melt-electrospinning system equipped with a CO 2 -laser melting device was developed. Rod-like samples were prepared from poly(lactide) pellets, and then fibers were produced from the samples using the new system. The effects of producing conditions on the fiber diameter were investigated. Furthermore, the physical properties of the fibers were investigated. The following conclusions were obtained: (i) in a special case, fibers having an average fiber diameter smaller than 1 mm could be obtained using the system developed; (ii) the fiber diameter could be decreased with increased laser output power, but the physical properties of the fibers such as the melting point and the molecular weight were decreased; and (iii) the electrospun fibers exhibited an amorphous state, and the annealed fibers exhibited an isotropic crystal orientation.
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