Kenji Tadano

Transition of ionic clusters in ionomers

Differential scanning calorimetric and thermal expansion measurements were made for the complex Zn(II) salts of ethylene-methacrylic acid copolymer with 1, 3-bis-aminomethylcyclohexane. One transition of the ionic clusters in the polymer matrix was found near 325 K as a peak on the DSC and thermal expansion curves. The transition exhibited a thermal hysteresis which was explained by the relaxational destruction/reformation of a structure in the inside of ionic clusters.

Dielectric properties of complex salts of Zn(ii) salts of ethylene-methacrylic acid copolymer with 1,3-bisamino-methylcyclohexane

Abstract Dielectric relaxations in complex salts of Zn(II) salts of ethylene-methacrylic acid copolymer (E-MAA), MAA content 5.4 mol%, with 1,3-bisaminomethylcyclohexane (BAC) were studied in detail. In E-MAA and the Zn(II) salts, β′ and γ relaxations were observed around 320 and 190 K at 1 kHz, which are attributed to micro-Brownian molecular motion of long segments and local molecular motion of short segments. When BAC is added to the two polymers, the β′ relaxation was replaced by α and β relaxations. The α and β relaxations were related to a glass-rubber transition of ionic clusters and to molecular motion of isolated salts and carboxylic acid not incorporated into the ionic clusters, respectively. From the above results, it was concluded that BAC strongly promotes the formation of ionic clusters.

Miscibility and crystallization of polytetrafluoro‐ethylene/poly(tetrafluoroethylene‐co‐perfluoropropylvinyl ether) blends

Miscibility and crystallization behavior have been studied for polytetrafluoroethylene(PTFE)/poly(tetrafluoroethylene-co-2 mol-% perfluoropropylvinyl ether)(PFA copolymer) blends by the use of differential scanning calorimetry, electron microscopy, X-ray diffractometry and dynamic mechanical spectroscopy. In the amorphous phase, the two components were miscible with each other over all blending ratios, and it was found that the PFA copolymer was compatible with the PTFE matrix, when the PFA content is ≤ 50 wt.-%, while PTFE was mixed in the PFA matrix when the PFA content is >50 wt.-%. All the blends were crystalline as well as PTFE and PFA. The crystallization behavior was closely connected to the polymer composition of the amorphous state described above. It was conjectured that the crystallization is controlled by the PTFE matrix when the PFA content is ≤ 50 wt.-%, while by the PFA matrix when the PFA content is >50 wt.-%.

Cubic Phases of 4'-n-docosyloxy-3'-nitrobiphenyl-4-carboxylic Acid (ANBC-22)

Dilatometric experiments have been performed on 4′-n-docosyloxy-3′-nitrobiphenyl-4-carboxylic acid (ANBC-22) which exhibits two types of thermotropic cubic phases (Cub I and II) on heating. Although the unit lattices of both Cub I and II, determined by X-ray diffraction measurements, slightly but certainly shrink with increasing temperature, the thermal expansion coefficients in both temperature regions were found to be positive. Thus, this study provided an experimental evidence that the number of molecules constructing the unit lattice of the two Cub phases decreases with temperature. Some aspects of the structural features of the Cub phases are discussed.

Studies of Lyotropic Liquid Crystalline Phase in Sodium Dodecylsulfate - Water System by Density and Conductivity Measurements

Abstract Phase transition of isotropic micelle solution (I) to middle (M1) phase in sodium dodecyl sulfate(SDS) - water system has been studied by density and conductivity measurements. Plots of density and conductivity versus SDS concentration exhibited a discontinuous change near the concentration of the transition (about 37 wt% of SDS). From these results, the mechanism of I-M1 phase transition was discussed.

Effect of branched alkyl groups on physical properties in poly(ethylene-co-branched alkyl methacrylate)s

SummaryPoly(ethylene-co-5.4 mol% n-alkyl/branched alkyl methacrylate)s (PEM) were prepared by a dehydrogenchloride reaction of poly(ethylene-co-5.4 mol% alkyl methacrylic chloride) with the corresponding alkyl alcohol to investigate effect of branching structure and length of alkyl ester on a few physical properties of PEM [glass transition temperature (Tg), degree of crystallinity in polyethylene region (Xc) and dielectric molecular motion], where the alkyl groups used here are n-propyl, n-butyl, n-hexyl, n-decyl, 2-ethylhexyl, 3,5,5-trimethylhexyl and 2-(1′,3′,3′-trimethylbutyl)-5,7,7-trimethyloctyl. In the n-alkyl methacrylate copolymers, Tg and Xc were almost unchanged with the presence of alkyl ester, but Tg increased and Xc decreased in the highly branched alkyl methacrylate copolymers even at the low methacrylate content of 5.4 mol%.

Structure and Molecular Motion in Complex Salts of Ethylene — Methacrylic Acid Copolymer With 1,3-Bis-Aminomethylcyclohexane and/or Zinc(II)

Formation of ionic clusters and molecular motion in the complex salts of Zn(II) salts of ethylene - methacrylic acid copolymer(E- MAA, content of MAA is 5.4 mol%) with 1,3-bis-aminomethylcyclohexane(BAC ) have been studied by small angle X-ray scattering and dielectric measurements. As content of BAC is increased, the size and concentration of ionic clusters increase and the a dielectric relaxation associated with a glass-rubber transition of ionic clusters appears around 350 K. It was concluded that BAC facilitates the formation of ionic clusters in the Zn(II) salts of E-MAA.