Spontaneous alternating copolymerization of isobutoxyallene with 4-phenyl-1,2,4-triazoline-3,5-dione

The spontaneous copolymerization of isobutoxyallene ( 1 ) with 4-phenyl-1,2,4-triazoline-3,5-dione ( 2 ) was carried out to afford a copolymer with a number-average molecular weight of 5900–10,300. The copolymer consisted of a 2,3-polymerization unit of 1 and a  NN polymerization unit of 2 , maintaining an alternating character regardless of the monomer feed ratio. The corresponding copolymerization of 1 with 2 in the presence of methanol afforded the adduct of the compounds without the polymer, indicating the generation of a zwitterion of 1 and 2 . © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1564–1571, 2001     

Reduction of the 2‐azetidinone moiety in the polymer main chain: A novel synthetic route to polyamine with hydroxymethyl pendant

A polymer with a 2‐azetidinone moiety in its main chain was efficiently synthesized by [2 + 2] cycloaddition of bisimine with bisketene. The bisketene was easily prepared by dehydrochlorination of the corresponding dicarboxylic acid chloride and was used without purification. The treatment of the obtained polymer with lithium aluminum hydride resulted in a reductive ring‐opening reaction of the 2‐azetidinone moiety in the main chain that gave the corresponding linear polyamine with hydroxymethyl side chains. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3789–3796, 2001     

Sorption and partial molar volumes of C2 and C3 hydrocarbons in polypropylene copolymers

The sorption of C₂ and C₃ hydrocarbons in two ethylene–propylene copolymers and a propylene homopolymer and the simultaneous dilation of the polymers were measured at temperatures of 287–363 K and pressures up to 4 MPa. The sorption isotherms were well described by the Flory–Huggins theory of dissolution. Dilation isotherms in the form of elongation versus pressure were similar in shape to the corresponding sorption isotherms. Solubility coefficients, partial molar volumes, and Flory–Huggins interaction parameters were determined from these isotherms. The thermal expansivities of the hydrocarbons dissolved in the polymers were 0.002–0.005 K^?1, and the Flory–Huggins interaction parameters depended not only on temperature but also on concentration. At 323 K, the calculated solubilities of propylene in the ethylene–propylene‐rubber regions of the copolymers were 1.8 times higher than in the amorphous regions of the propylene homopolymer. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1255–1262, 2001     

Macroporous Morphology of the Titania Films Prepared by a Sol-Gel Dip-Coating Method from the System Containing Poly(Ethylene Glycol). III. Effect of Chemical Additives

The variation of macroporous morphology has been studied for the titania (TIO₂) films prepared by a sol-gel dip-coating method from the system containing poly(ethylene glycol) (PEG) under the addition of various types of organic solvents. The influence of externally-added solvent is interpreted by considering the compatibility between PEG and the solvent mixture, the volatility of the solvent mixture, and the polycondensation rate of titania oligomers. The macroscopic domain formation is remarkable when the compatibility between the solvent mixture and PEG is relatively poor and the boiling point of external solvent is relatively low.     

Profiles of ethylene polymerization with zirconocene–trialkylaluminum/borane compound

Ethylene polymerization was conducted with bis(cyclopentadienyl)zirconium dichloride (1) and rac-dimethylsilylenebis(indenyl)zirconium dichloride (2) combined with trialkylaluminum (AlR₃; R=methyl (Me), ethyl (Et), isobutyl (iBu))/triphenylcarbenium tetrakis(pentafluorophenyl)borate (Ph₃CB(C₆F₅)₄) or tris(pentafluorophenyl)borane (B(C₆F₅)₃) to study the effect of cocatalysts on polymerization rate (R_p). When AlMe₃ was used, no activity or very low activity was observed with both zirconocenes regardless of the borane compounds used. The replacement of AlMe₃ to AlEt₃ or AliBu₃ with 1–AlR₃/Ph₃CB(C₆F₅)₄ caused polymerization and induction time was observed to reach the maximum R_p. Especially in the case of using AlEt₃, it took about 30 min to show the activity. When B(C₆F₅)₃ was used, AlEt₃ was not effective but AliBu₃ gave the highest activity among all the combinations of AlR₃ and the borane compounds. In the case of polymerization with 2 using Ph₃CB(C₆F₅)₄, high activity was observed with both AlEt₃ and AliBu₃ without any induction period. When B(C₆F₅)₃ was used instead of Ph₃CB(C₆F₅)₄, very low activity was observed with AlEt₃. On the other hand, high activity was observed with AliBu₃, and the maximum R_p was found at the beginning of the polymerization. The effect of AlR₃ on the formation of active species was discussed based on these results.     

Ab initio molecular orbital study of Fe(CO) n (n = 1–3)

Geometry optimization was performed for the ground states of FeCO, Fe(CO)₂, and Fe(CO)₃ at various levels of ab initio calculations, and the bond lengths and dissociation energies obtained were in reasonable agreement with experimental results. The nature of bonding was studied for these molecules using a complete-active-space self-consistent-field method. From the Mulliken population analysis, it was found that the traditional donation and back donation mechanism is valid for these molecules, including Fe(CO)₃, which has a pyramidal structure. Received: 27 September 1999 / Accepted: 13 January 2000 / Published online: 19 April 2000     

Electron transport membrane: Preparation of polypeptide membrane with spacers between the polymer matrix and viologen moiety and their application to an electron transfer reaction

Polypeptide membranes with several lengths of spacers [? (CH₂)_n? ; n = 3, 6, 12] between the polymer matrix and viologen moiety as a functional group were prepared. Reduction of K₃Fe(CN)₆ with Na₂S₂O₄ across the obtained membrane in aqueous media were carried out and reduction rate of K₃Fe(CN)₆ across the membrane of n = 6 was faster than that of n = 3. However, the reduction of the membrane (n = 12) did not proceed chemically and electrochemically at all.     

Conductive diamond hollow fiber membranes

Boron-doped diamond hollow fiber membrane (BDD–HFM) was fabricated as a novel type of porous conductive diamond. BDD–HFM was obtained by deposition of BDD polycrystalline film onto a quartz filter substrate consisting of quartz fibers, followed by etching of the substrate in HF/HNO₃ aqueous solution. Cross-sectional scanning electron microscope (SEM) observation showed the inner diameter and wall thickness of the BDD hollow fibers were in the range of 0.4–2 and 0.2–2 μm, respectively. The BDD–HFM electrode exhibited a relatively large double-layer capacitance (ca. 13 F g⁻¹) in 0.1 M H₂SO₄. Electrochemical AC impedance properties were simulated using an equivalent circuit model containing a transmission line model, which indicated characteristics of a porous electrode material.