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.

ABSTRACT:The relationships between the properties and structure are discussed for poly(vinyl alcohol)(PVA)/silica composites prepared through the sol-gel process. The composites became stiff and brittle with increasing the silica content. The properties of the composites were changed drastically at around the composition of PVA/silica ϭ 70/30 wt %. For example, there was no large change in the Young's modulus above 30 wt % of silica content (Pure PVA: 31.8 MPa, silica 30%: 52.6 MPa, silica 50%: 55.2 MPa). Consequently, it was considered that the three-dimensional network structure of silica could be formed in the composite with more than 30 wt % of silica in PVA. From this behavior, it could be considered that the crystal growth of PVA was remarkably inhibited by silica network.

EHEC O157:H7 clade 6 strains harboring stx2a and/or stx2c and clade 8 strains harboring stx2a or stx2a/stx2c were frequently associated with childhood HUS cases in Japan. Rapid and specific detection of such lineages are required for infection control measures.

Rodlike polymer samples were made from three kinds of poly(ethylene terephthalate) (PET) pellets with different intrinsic viscosities (IV), and from polyalirate (Vectra) pellets. PET and Vectra fibers were produced using a melt-electrospinning system equipped with a CO 2 -laser melting device from these rodlike samples. The effects of IV value and laser output power on the fiber diameter of PET were investigated. Furthermore, the effect of the laser output power on the fiber diameter of Vectra was investigated. The crystal orientation of these produced fibers was also investigated by X-ray photographs. The following conclusions were reached: (i) the diameter of PET fiber decreases with increasing laser output power; (ii) the minimum average diameter of PET fibers is scarcely influenced by the value of IV; (iii) the electrospun PET fibers show isotropic crystal orientation; (iv) fibers having an average fiber diameter smaller than 1 mm cannot be obtained from PET and Vectra using the system developed; and (v) preferred liquid crystal orientation can be seen in electrospun Vectra fibers.

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