Novel photocurable monomers: The synthesis of difunctional vinyl ethers with a phosphonate group and difunctional 1‐propenyl ethers with a phosphonate group and their photoinitiated cationic polymerization

Phosphorus‐containing vinyl ether monomers and 1‐propenyl ether monomers were prepared by the regioselective addition reaction of glycidyl vinyl ether (GVE) or 1‐propenyl glycidyl ether with diaryl phosphonates with quaternary onium salts as catalysts. The reaction of GVE with bis(4‐chlorophenyl) phenylphosphonate gave bis[1‐(4‐chlorophenoxy methyl)‐2‐(vinyloxy)ethyl]phenylphosphonate in a 68% yield. The structures of the resulting phosphorus‐containing vinyl ether monomers and 1‐propenyl ether monomers were confirmed by IR and ¹H NMR spectra and elemental analysis. Photoinitiated cationic polymerizations of the resulting phosphorus‐containing vinyl ether monomers and 1‐propenyl ether monomers were investigated with photoacid generators. The polymerization of vinyl ether groups and 1‐propenyl ether groups of the obtained monomers proceeded very smoothly with a sulfonium‐type cationic photoinitiator, bis[4‐(diphenylsulfonio)phenyl]sulfide‐bis(hexafluorophosphate), upon UV irradiation. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3105–3115, 2005     

Phase Matching Property of Cross Polarization Four Wave Mixing in BaTiO3 Crystal

Four wave mixing (FWM) is of considerable interest in generation of a phase conjugate beam with photorefractive crystals. The common methods of FWM are parallel polarization FWM and cross polarization FWM. In this paper, we analyze the phase matching property of the latter. First, we consider the phase matching condition, and derive equations representing the angler relationship of interacting beams. Then, we consider the phase mismatching which is caused by shift of the probe beam angle from the phase matching condition, and calculate the effect of the shift of this angle on the amount of phase mismatching. We also determine and closely examine the coupling constant.     

Electron microscopy of submicron particles in natural waters—Morphology and elemental analysis of particles in fresh waters

Submicron particles larger than about 0.1m in pond and river waters were collected on a carbon film mounted on a specimen grid by centrifugation and then studied morphologically and analyzed for major elements heavier than sodium, with a high-resolution transmission electron microscope equipped with an energy dispersive X-ray analyzer. If available, the data were compared with those of particles artificially prepared under various conditions. Four typical particles—aluminosilicate, quartz, fine-particle aggregates containing silica and iron(III) oxide, and microorganisms—were found in fresh waters.     

Author index to volume 49

The de-excitation rate constants of Ne(³P₂, ³P₀ and ³P₁) by N₂ and SF₆ were measured using a pulse radiolysis method combined with optical absorption spectroscopy. A new absorption law which relates the relative concentration S of absorbing atoms to the measured transmittance T, i.e. in S = Σ¹¹_{i = 0}a_iTⁱ, was used for analyzing the data. The presence of a small amount of SF₆ in the sample gas mixtures permitted removal of some artifacts due to thermal electrons for determining the rate constants.     

Observation of optical activity in polythiourethane obtained by the controlled cationic ring‐opening polymerization of chiral cyclic thiourethane derived from serine

The secondary structure of an optically active polythiourethane [(? CH₂C*H(CO₂Me)NHCOS? )_n] was evaluated with ¹H NMR, IR, and circular dichroism (CD) spectroscopy. Hydrogen bonds between the carbonyl and NH groups in the thiourethane group constrained the main chain of the chiral polythiourethane precisely under the direction of chirality in the main chain, whereas the racemic polymer was also constrained but randomly. The secondary structure of the polythiourethane in CHCl₃ changed noticeably in the presence or absence of trifluoroacetic acid, which eliminated constraining intramolecular hydrogen bonds. IR spectroscopy suggested that the secondary structure was almost identical in solid and solution states. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1554–1561, 2005     

A bound on the Castelnuovo-Mumford regularity for curves

Recall that a projective curve in with ideal sheaf is said to be n-regular if for every integer and that in this case, it is cut out scheme-theoretically by equations of degree at most n. The purpose here is to show that an irreducible, reduced, projective curve of degree d and large arithmetic genus satisfies a smaller regularity bound than the optimal one . For example, if then a curve is -regular unless it is embedded by a complete linear system of degree . Received: 29 May 2000 / Published online: 24 September 2001     

Synthesis and crosslinking reaction of poly(thiourethane)s having a siloxane moiety in the side chain

Poly(thiourethane)s having a siloxane moiety in the side chain were synthesized with a 5‐membered cyclic dithiocarbonate (DTC) having a siloxane group as a building block. The synthetic pathway consisted of (1) an addition reaction of the DTC with diamines and (2) polyaddition reactions of the resulting dithiols with diisocyanates. The siloxane moiety in the polymer side chain underwent a self‐condensation reaction upon exposure to moisture, and this led to a successful crosslinking reaction of the poly(thiourethane). The crosslinking on a silicate surface was accompanied by condensation between the siloxane side chain of the polymer and the silanol group on the surface, giving the corresponding surface that was permanently coated with the crosslinked polymer. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6492–6502, 2005     

Origin of the color of π‐conjugated columnar polymers: Poly(p‐n‐octylthiophenyl)acetylene prepared using a [Rh(norbornadiene)Cl]2 catalyst

Highly stereospecific polymerization of a novel sulfur containing aromatic acetylenes, that is, (p‐n‐octylthiophenyl)acetylene (pOctSPA), was successfully performed using the Rh complex, [Rh(norbornadiene)Cl]₂‐TEA, catalyst in the presence of various solvents under mild conditions. The resulting polymers were characterized in detail by ¹H NMR, ESR, laser Raman, diffuse reflective UV‐Vis (DRUV‐Vis), and wide angle X‐ray diffraction methods. The data showed that the resulting polymers bear cis‐transoid form, which can induce the cis‐to‐trans isomerization when the cis polymers are subjected to pressure at room temperature under vacuum, breaking rotationally the cis C?C bonds in the main‐chain giving two kinds of π‐radicals, the so‐called cis radical and trans radical as the origin of a polymer magnet like a novel spin glass material. Further, the resulting cis poly(acetylene)s were found to have a helical main‐chain, which is packed in pseudohexagonal crystal called π‐conjugated columnar or nano π‐conjugated columnar as a novel color controllable material. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2836–2850, 2005