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Poly(ether sulfone)s containing pendant sodium sulfonate groups were prepared by the aromatic nucleophilic substitution reaction of 4,4′‐dichlorodiphenylsulfone (1) and sodium 5,5′‐sulfonylbis (2‐chlorobenzenesulfonate) (2) with bisphenols (3) in the presence of potassium carbonate in N,N‐dimethylacetamide. A new monomer 2 containing the sodium sulfonate groups was synthesized by the sulfonation of 1 with fuming sulfuric acid. The polycondensation proceeded smoothly at 170°C and produced the desired poly(ether sulfone)s containing the sodium sulfonate with inherent viscosities up to 1.2 dL/g. The polymers were quite soluble in strong acid, dipolar aprotic solvents, m‐cresol, and dichloromethane. The thermogravimetry of the polymers showed excellent thermal stability, indicating that 10% weight losses of the polymers were observed in the range above 460°C in nitrogen atmosphere. Both the glass transition temperatures and hydrophilicity of the polymers increased with increasing their concentrations of sodium sulfonate groups. © 1993 John Wiley & Sons, Inc.

Poly(propyleneimine)-based liquid crystalline dendrimers (PPILCDs) with a relatively flexible dendritic scaffold were successfully prepared by the Michael addition reaction of poly(propyleneimine)s with ω-(4‘-cyanobiphenyloxy)alkyl acrylate (1). The structures of PPILCDs were characterized by IR spectroscopy, 1H NMR spectroscopy, and MALDI−TOF mass spectroscopy. PPILCDs exhibit smectic liquid crystalline natures between −7 and +89 °C. The temperature range of the smectic phases expanded with increases in the generation of the dendritic core and the length of flexible spacers. The homeotropic orientation was allowed to take place in PPILCD with the second-generation scaffold, when it was slowly cooled.

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Spherulitic textures of poly[tetrafluoroethylene‐co‐(perfluoropropyl vinyl ether)] (PFA) were examined in detail using polarized optical microscopy. The PFA consisting of random comonomer units among the tetrafluoroethylene units crystallizes as spherulites composed of lamellae, although polytetrafluoroethylene usually forms extended‐chain crystals because of the rigid nature of 13/6 helices. The spherulites obtained exhibit positive birefringence since the polymer crystal has a larger refractive index in the direction normal to the chain than that along it. These fluorocopolymers exhibit a thicker long period of at least 30 nm in small‐angle X‐ray scattering profiles than is generally the case for hydrogenated crystalline polymers. In these copolymers, we consider the formation of a switchboard‐type lamellae model according to P. J. Flory's suggestion. In addition, we find the overlooked reflections near 2θ = 8.5° based on the superlattice in wide‐angle X‐ray diffraction profiles of fluorocopolymers with high reproducibility. From this result, it was found that the lattice constant that was previously proposed is required to be refined to twice the value on the a‐ and b‐axes of the reciprocal lattice to assign all the reflection indices. Copyright © 2007 Society of Chemical Industry

ABSTRACT:The composite materials containing metal Ni powder of 5-15 mm in size were prepared by use of the matrix epoxy resin of glycidyl amine crosslinked with bis-4-amino-3-methylcyclohexyl methane and 2,4-diamine 3,5-dimethyltoluene. Dynamic viscoelastic properties of the composites at various volume fraction ( F p ) of Ni powder have been measured over the temperature range from 30 to 300ЊC. The peak temperatures in dynamic loss modulus-temperature diagrams of the composite increased with increasing F p , although the peak position was abruptly shifted to lower temperatures in the range of F p more than 0.245. At this high concentration of F p , agglomeration of the particles occurring in the composite lead to reduction of the interaction between Ni particle and epoxy resin. Parallel studies on the thermal conductivity ( l) of the composites materials showed that the value of l at F p Å 0.245 increased by approximately 7 times that of the original epoxy resin. The shape of Ni particles also affected the thermal durabilities of the composites; the rough surface of Ni powder yields a higher storage modulus of the composite than that of the materials containing the powder with a smooth surface, which had been brought through a ball-milling process. The finding suggested that the increasing in specific surface area of the powder improved the thermal durability of the composites as well as their mechanical properties.