Vapor deposition polymerization of heteroatom-bridged [2.2]paracyclophanes: 1,9-dithia[2.2]paracyclophane and 1,9-dithia[2.2]paracyclophane-1,1,9,9-tetroxide

1,9-Dithia[2.2]paracyclophane-1,1,9,9-tetroxide ( 3 ) was synthesized as white needles in a high yield from 1,9-dithia[2.2]paracyclophane ( 2 ) by oxidation with m-chloroperbenzoic acid, and its molecular structure was determined with single-crystal X-ray diffraction analysis. Vapor deposition polymerizations of 2 and 3 gave amorphous and brittle polymer films along with considerable amounts of nonpolymeric byproducts. A polymer film from 2 was a copolymer of p-(phenylene-methylenesulfide) with p-(phenylene-methylene) units, and a polymer film from 3 was a homopolymer of p-(phenylene-methylene) units with head-to-tail, head-to-head, and tail-to-tail placements. The elimination of sulfur atoms in 2 and sulfone units in 3 took place during their pyrolysis reactions. Plausible mechanisms for vapor deposition polymerizations of both cyclophanes are proposed. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1892–1900, 2001     

Periodic solutions of the Navier–Stokes equations in a perturbed half‐space and an aperture domain

We shall construct a periodic strong solution of the Navier–Stokes equations for some periodic external force in a perturbed half‐space and an aperture domain of the dimension n?3. Our proof is based on L^p–L^q estimates of the Stokes semigroup. We apply L^p–L^q estimates to the integral equation which is transformed from the original equation. As a result, we obtain the existence and uniqueness of periodic strong solutions. Copyright © 2005 John Wiley & Sons, Ltd.     

Synthesis and radical polymerization of dissymmetric fumarates with alkoxyethyl and bulky siloxy groups

Novel dissymmetric fumarate monomers ( 1a – c ) having both an alkoxyethyl group such as 2‐methoxyethyl ( a ), 2‐(2‐methoxyethoxy)ethyl ( b ), and 2‐(2‐(2‐methoxyethoxy)ethoxy)ethyl ( c ) and a bulky 3‐[tris(trimethylsiloxy)silyl]propyl group were synthesized successfully, and their radical homopolymerizations and copolymerizations with styrene (St) were investigated. Monomer reactivities of the 1a – c in homopolymerizations were enhanced with an increase in the length of alkoxyethyl chains. The enhancement in the reactivity was explained with the suppression of the termination reaction, resulting from the increased steric hindrance induced by an increase in the size of alkoxyethyl chains. Copolymerizations of the 1a – c with St were carried out in bulk in the presence of AIBN at 60 °C, and their copolymerizations proceeded in a highly alternating tendency regardless of alkoxyethyl chain lengths. The Q, e values of the 1a – c were obtained as 0.48, +1.55 for the 1a , 0.66, +1.16 for the 1b , and 0.60, +1.16 for the 1c , respectively, from the terminal model reactivity ratios, and the 1a – c were found to be conjugative, electron‐accepting monomers. Membranes containing the 1a unit, prepared by the copolymerization of 1a with N‐vinylpyrrolidone (NVP) and terpolymerization of 1a , NVP, and 2‐hydroxyethyl methacrylate, have higher oxygen permeability than those containing no 1a unit, and also they have much better transparency compared with the membranes containing 3‐[tris(trimethylsilyloxy)silyl]propyl methacrylate unit. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 420–433, 2009     

Confirmation/Observation of Hindered E2 Strengths in-16,18C

The lifetime of the first excited 2~+ state in ~(18)C was measured using an upgraded recoil shadow method to determine the electric quadrupole transition.The measured mean lifetime is 18.9±0.9 (stat)±4.4 (syst) ps,which corresponds to a B(E2;2~+_1→0~+_(gs)) value of (4.3±0.2±1.0) e~2fm~4,or about 1.5 Weisskopf units.The mean lifetime of the first 2~+ state in ~(16)C was remeasured to be about 18 ps,about four times shorter than the value reported previously.This discrepancy was explained by incorporating the γ-ray angular distribution measured in this work into the previous measurement.The observed transition strengths in ~(16,18)C are hindered compared to the empirical transition strengths,indicating that the anomalous hindrance observed in ~(16)C persists in ~(18)C.