Yuhsuke Kawakami

Surface Active Properties of Silicone Containing Polymers

SummaryThe efficiency and durability of surface modification of poly(methyl methacrylate) [PMMA] by silicone containing graft and random copolymers were studied by contact angle measurement of water droplet. The efficiency principally depended on the content of the siloxane; however, the durability of surface modification to hexane extraction differed according to the type of the silicone polymer and the siloxane content.

Enhancement of oxygen permselectivity of polydimethylsiloxane-b-polycarbonate film by the surface modification with fluorine-containing polymer

SummaryBoth oxygen permeability coefficient(PO2) and separation factor (α = PO2/PN2) through polydimethylsiloxane-b-polycarbonate(PDMS/PC) film were improved by the addition of small amounts(1.0 wt%) of the fluorine-containing polymer. This improvement was considered to be caused by the selective solubilization of oxygen in the surfaceaccumulated fluorine polymer domain.

Convenient synthetic routes to α-oligosiloxanylacrylonitriles

Abstract Novel 1,4-elimination reaction of C,N-bis(trimethylsilyl)-C- trimethylsiloxymethylketenimine and retro Diels-Alder reaction of 2-oligosiloxanyl-5-norbornene-2-carbonitrile cleanly gave α-oligosiloxanylacrylonitriles in excellent yield.

Regioselectivity control in alkylation reactions of indolyl ambident anion

The regioselectivity of N- and C-3(β)-alkylations of indolylmetal salts was studied under various conditions. The effect of counter metal ion is crucial in determining the regioselectivity. In tetrahydrofuran, exclusive N-alkylation occurred with the potassium salt, but the extent of C-3-alkylation increased with the sodium and lithium salts and became predominant with the magnesium bromide salt. However, N-alkylation was favoured generally in more polar solvents and for alkyl toluene-P-sulphonates it was favoured even with magnesium bromide salts. The reactivity and regioselectivity of the alkylations were correlated with the calculated electron density of the indolyl anion and with 13C n.m.r. chemical shifts of the metal salts.

Syntheses of polyamide-poly(methyl methacrylate) graft copolymers by polycondensation reactions of macromonomers

SummaryDicarboxyl-terminated macromolecular monomers (macromonomers) were synthesized by radical polymerization of methyl methacrylate in the presence of thiomalic acid as a chain transfer agent. This macromonomer and sebacic acid were condensed with diamines (p,p′-diaminodiphenyl ether, p,p′-diaminodiphenylmethane and m-phenylenediamine) by triphenylphosphitepyridine system. Thus, graft copolyamides of well-defined structure and composition were readily prepared. This is the first example of the polycondensation reactions of macromonomers.

HYDROXY FUNCTIONALIZED TERTIARY PHOSPHINES

Abstract Some new tertiary aralkylphosphine sulfides having OMe, COOMe, and OH groups were synthesized. These were reduced to the tertiary phosphines.

Enhancement of Ring-Opening of Tetrahydrofuran by Trimethylsilyl Chloride in the Presence of Metal Oxides

Abstract Tetrahydrofuran was cleaved by trimethylsilyl chloride in the presence of metal oxides like alumina in hexane even at 50[ddot]C.

Asymmetric Selection by Optically Active Polymers in Phase-Transfer System

Phase-transfer catalyst systems have been deeply concerned with the various aspects of polymer chemistry in recent years. Imai et al showed that phase-transfer catalysts like crown ethers or ammonium salts were very effective in condensation polymerizations.