A novel spin-finishing method for antistatic modification of polyester fiber. Surface reaction onto amine-containing copoly(amide-ethers) blended with polyester fiber

Copoly(amide-ethers) containing two types of tertiary amine units were made as antistatic modifiers for poly(ethylene terephthalate) (PET) fibers. The filaments of the copolymers were melt-spun and reacted with three alkylating agents in order to quaternize the tertiary amine into a sulfo-betaine, a carbobetaine, and an ammonium ion. The apparent electric resistivity of the filaments was greatly reduced by this reaction, being in the range of 10⁶ to 10⁸ Ω/cm. However, because these quaternized copolymers incurred decomposition during blend spinning with PET, a blend PET fiber containing one type of copoly(amide-ether) was melt-spun and subjected to quaternization of the amino groups as well as to surface crosslinking with various alkylating and epoxy agents. The quaternized blend fibers obtained showed improved antistatic properties compared with the original blend fiber. Particularly, the fibers crosslinked with epoxy compounds were found to have the best antistatic properties that had ever been attained with this type of modification. The antistatic properties were retained even after dyeing, because both hydrophilic and ionic groups had been effectively immobilized on the surface. Since this quaternization and crosslinking could be conducted on-line with spinning and drawing within a short reaction time, this modification technique is called “spin-finishing method”, which should be superior to the conventional methods in terms of cost performance and productivity.     

Conductive Papers Containing Metallized Polyester Fibers for Electromagnetic Interference Shielding

Conductive papers were developed for preventing or reducing electromagnetic interference (EMI), and their shielding efficiency was evaluated. This type of conductive paper consists of wood pulp, synthetic pulp and metallized polyester fibers (0.5–2.0 mm long and 14 m in diameter) whose surfaces are coated with nickel alone (Ni-PET) or copper and nickel double layers (Ni-Cu-PET) by electroless plating. In this report, the effect of the characteristics of these metallized fibers, such as their conductivity, geometry and the concentration of fibers in paper, which lead to high efficiency for shielding effectiveness is discussed. For instance, one of the conductive papers (80 g/m2) which was prepared by mixing 40% Ni-Cu-PET and 60% synthetic polyethylene pulp showed over 40 dB shielding effectiveness between 10 MHz and 1 GHz.     

Polymerization of propylene over metal oxides-supported TiCl3 catalysts

Summary Several metal oxides-supported TiCl₃ catalysts were prepared and propylene polymerization was conducted over them without cocatalysts. It was found that isotactic polymerization of propylene took place effectively over them.     

Polymerization of propylene over titanium exchanged Y-zeolite

Summary It was found that isotactic polymerization of propylene took place over titanium ion-exchanged Y-zeolite without organometallic compounds. The results obtained have led to the conclusions that Ti⁴⁺ species as well as Ti³⁺ species are active for the polymerization and that neither Ti-alkyl bonds nor Cl ligands are necessarily essential for polymerization of propylene.     

Graft copolymerization of styrene onto cellulose acetate p-nitrobenzoate by chain transfer reaction

Styrene was grafted onto cellulose acetate p-nitrobenzoate (CANB) by chain transfer reaction of growing polymer radicals to the pendant nitro groups of CANB. A copolymer with a branch for every 17.2 nitro groups was obtained. This result indicates that the pendant aromatic nitro group is more effective in obtaining a graft copolymer by radical mechanism than pendant double bond on the trunk polymer previously reported, where graft copolymers with a branch for several hundred of double bonds are produced.     

Radiation-induced graft copolymerization of mixtures of styrene and n-butyl acrylate onto cellulose and cellulose triacetate

Mixtures of styrene and n-butyl acrylate of various compositions were grafted onto cellulose and cellulose triacetate fibers preirradiated with γ-rays at 0°C in air. Monomer reactivity ratios of the grafted copolymers were found to be different from those of the nongrafted copolymers or those of AIBN-initiated copolymers. The active species initiating the graft copolymerization were trapped radicals for cellulose and peroxides for cellulose triacetate. Kinetic investigations of the graft copolymerization of styrene onto preirradiated cellulose triacetate fibers were also carried out, and it was found that the kinetic scheme for radical polymerization is also applicable to graft copolymerization in a heterogeneous system.     

Bromine addition and successive amine substitution of mesoporous ethylenesilica: Reaction, characterizations and arsenate adsorption

Bromination and subsequent ethylenediamine substitution of the CC double bond in mesoporous ethylenesilica were carried out to explore the characteristics of this periodic mesoporous organosilica. The structures of the products (BrPMO and EDA–BrPMO, respectively) were analysed by IR, Br K-edge EXAFS and NMR spectroscopies, as well as X-ray diffraction and nitrogen adsorption. We showed (1) that the formulae of the two products that formed were [CHBrSiO_1.5]_0.45[CHSiO_1.5]_0.55 and [NH₂CH₂CH₂NHCHSiO_1.5]_0.05 [CHBrSiO_1.5]_0.40[CHSiO_1.5]_0.55, respectively, (2) that the addition of Br₂ at room temperature occurred on the CC double bonds with disturbing the framework structure, (3) that IR absorption band of CC bonds that reacted with Br₂ is significantly different from that of inactive CC bond, (4) that the length of the C–Br bond was considerably longer than in conventional alkyl bromides, and (5) that a large proportion of the ν(C–Br) band remained at the same position in the IR absorption spectrum after the ethylenediamine (EDA) substitution, while a new ν(C–Br) absorption also appeared. The mechanisms of these reactions are discussed at both the micro and mesoscopic levels.

Arsenate adsorption on EDA–BrPMO, in which the EDA is directly bound to the “surface” of the mesopores, was compared with adsorption on EDA–Pr–PMO, which was prepared by the direct synthesis of 3-chloropropyl-functionalized mesoporous ethanesilica followed by the substitution of Cl with EDA. The strength of the adsorption, as measured with the distribution coefficient, was greater for the former adsorbent than the latter. The origin of this difference was attributed to the distance between amino group and the surface.     

Synthesis of High Density and Transparent Forsterite Ceramics Using Nano-Sized Precursors and Their Dielectric Properties

Forsterite (Mg₂SiO₄) ceramics were prepared using Mg(OH)₂ and SiO₂ as precursors, and the effect of powder characteristics of Mg(OH)₂ on calcination and sintering was investigated. The use of highly dispersed Mg(OH)₂ powder (HD powder) resulted in a lower calcination temperature. Forsterite powder of high homogeneity and small particle size prepared from the HD powder enabled synthesis of high-density forsterite ceramics by ordinary sintering without applying external pressure. Moreover, transparent forsterite ceramics were successfully synthesized through addition of excess Mg to the precursors to compensate for Mg evaporated during the sintering process. Subsequent dielectric measurements revealed that the transparent forsterite ceramics had a very low dielectric loss (tan δ<10⁻⁴).     

A facile antistatic modification of polyester fiber based on ion-exchange reaction of sulfonate-modified polyester and various cationic surfactants

A new technique for imparting antistatic properties to poly(ethylene terephthalate) (PET) fiber has been developed. In this technique, blend polyester fibers containing poly(ethylene terephthalate/5-sulfoisophthalate) (SIP-PET) were prepared by blend spinning and then treated with various cationic surfactants in the process of dyeing. The surfactants could effectively be immobilized on the fiber as the counter cations of the sulfonate groups of the 5-sulfoisophthalate (SIP) units and aid the release of static electrons formed in the fiber. Thus, the half-life time (t_1/2) of leakage of static charge and the surface resistivity (Rs) of the blend PET fibers became much lower after treating. The best result was obtained with a methylated quaternary ammonium salt of a stearylamine-ethylene oxide (EO) adduct or hydrochloride of a laurylamine-EO adduct as the surfactant of which the number of EO units was around ten. Even after five washing cycles the t_1/2 value of the fibers treated with these surfactants was kept lower than 30 s with the Rs value maintained in the order of 10¹³ Ω cm^-2. Therefore, the present technique could be useful for practical production of polyester fibers with “semi-permanent” antistatic properties which can be recovered by re-treatment even if they were lost.