Takahisa Misono

Synthesis and properties of N-alkyl-N′-aryl-3,4:9,10-perylenebis(dicarboximide)

Abstract N′-Alkyl-N′-aryl-3,4:9,10-perylenebis(dicarboximide) (alkyl = isobutyl, pentyl, hexyl, octyl, etc.; aryl = phenyl, p-tolyl, p-methoxyphenyl, etc.) were prepared by the condensation of N-alkyl-3,4:9,10-perylene-tetracarboxylic monoanhydride monoimide with arylamines (aniline, p-toluidine, p-anisidine, o-phenylenediamine, etc.). The properties of these derivatives as pigments were tested, and also the thermal stability of 3,4:9,10-perylenebis(dicarboximide) derivatives was measured.

Preparation of continuous zirconia fibres from polyzirconoxane synthesized by the facile one-pot reaction

A one-pot reaction of zirconium oxychloride octahydrate (ZOC) with ethyl acetoacetate (Hetac) in the presence of triethylamine was investigated. The reaction was carried out in molar ratios of Hetac/ZOC=1.0, 1.5, 2.0 to give highly viscous solutions with good spinnability and stability to self-condensation. Polyzirconoxanes (PZOs) were isolated as white powders by reprecipitation of the solutions with tetrahydrofuron (THF)-hexane that were soluble in acetone, methanol and THF. The molecular weight of PZO was Mn=1000–2000, and was dependent on the molar ratio and the reaction time. Dry spinning of the solution (Hetac/ZOC=1.5) containing 3mol% tris(acetylacetonato)yttrium [Y(acac)3] gave continuous precursor fibres (3.0Y–PZO). Yttria stabilized zirconia fibres of 12–18 μm diameter with a tensile strength of 1.4GPa were obtained by heat treatment of the 3.0Y–PZO at 1100 or 1200 °C. The fibre consisted of submicrometre-sized particles of tetragonal crystallites.

Preparation of monolithic SiO2TiO2 gels by condensation polymerization of silicic acid and titanium chelates

Abstract The preparation of monolithic gels as a precursor for SiO 2 TiO 2 glasses via polytitanosiloxanes was investigated. The gels were obtained from polytitanosiloxanes formed by condensation polymerization of titanium chelates and silicic acid. Silicic acid was extracted with tetrahydrofuran from an aqueous sodium metasilicate solution neutralized with hydrochloric acid. Titanium chelates used were bis(acetylacetonato)titanium diisopropoxide (ATP) and bis(ethyl acetoacetato)titanium diisopropoxide (ETP). Monolithic gels with a TiO 2 content of less than 20 mol% were formed by the reaction of silicic acid with ATP, whereas the reaction with ETP provided transparent monolithic SiO 2 TiO 2 gels of 5.7–94 mol% TiO 2 . Heat treatment of the gels gave monolithic SiO 2 TiO 2 glasses.

Preparation of SiO2TiO2 fibers from polytitanosiloxanes

Abstract Continuous oxide fibers SiO 2 TiO 2 were obtained by drying spinning of precursor fibers from polytitanosiloxanes (PTS) prepared by the reaction of silicic acid (SA) with titanium chelate (PTP) in the molar ratio of SA/PTP = 0.5 (PTS-0.5) and 1.0 (PTS-1). The precursor fibers, being golden-yellow, turned black and then white on pyrolysis. The fibers underwent decomposition with removal of organic groups to form black fibers at 200–500°C and white fibers at about 1000°C. Crystallization of TiO 2 took place at 850°C (PTS-0.5) and 950°C (PTS-1). Rearrangement of SiOTi linkage of the polymer back-bone into SiOTi m ay lead to the formation of TiO 2 clusters and subsequent crystallization of TiO 2 .

Synthesis and properties of long and branched alkyl chain substituted perylenetetracarboxylic monoanhydride monoimides

Abstract N-Alkyl-3,4:9,10-perylenetetracarboxylic monoanhydride monoimides were prepared by the condensation of 3,4:9,10-perylenetetracarboxylic monoanhydride monopotassium salt with alkylamines (alkyl = decyl, lauryl, tetradecyl, cetyl, stearyl, etc.). N-Branched alkyl substituted perylenetetracarboxylic monoanhydride monoimides were prepared by the hydrolysis of N,N′-dialkyl-3,4:9,10-perylenebis(dicarboximide)s with potassium hydroxide. The absorption spectra of paint film, thermal stability and solubilities of these monoimides were investigated.

Sol–gel preparation of borosilicates

Abstract Polyborosiloxanes as a precursor for borosilicate gel plates and fibers were obtained by the reaction of silicic acid and boron tri- n -butoxide followed by alkoxylation with 1-butanol. Gel fibers were prepared after concentration and aging of the polymer solutions with molar ratios of silicic acid to boron tri- n -butoxide of 7/3–2/3. Further aging of the solutions gave gel plates with cracking, depending on boron content. Spectral and chemical analyses showed that the borosiloxane bond formation initiated during polymerisation reaction and is enhanced by heat treatment .

Preparation of monolithic gels SiO2MxOy (M = Al, Zr) by the reaction of silicic acid with metal chelate compounds

Abstract Preparation and thermal treatment of monolithic gels SiO2MxOy (M = Al, Zr) were investigated. The gels were prepared via polymetalloxane compounds formed by condensation polymerization of silicic acid with metal chelate compounds. The reaction gave a homogeneous solution of the polymer which underwent further condensation to form transparent monolithic gels of 3.0–89 mol% Al2O3 and 5.7–94 mol% ZrO2. Thermal treatment of gels provided oxide glasses. The X-ray analysis showed that SiO2Al2O3 gels heated up to 1000°C were amorphous regardless of composition while SiO2ZrO2 gels showed crystallization due to ZrO2 depending on the thermal treatment temperature and their composition.

Preparation of polymetalloxanes as a precursor for oxide ceramics

The reaction of di-t-butoxysilanediol with bis(acetylacetonato)titanium di-iso-propoxide gave cyclic titanosiloxane. Silicon tetraacetate was reacted with boron tri-n-butoxide in THF to form polyborosiloxanes with molecular weight around one thousand. Monolithic SiO2B2O3 gels were obtained on aging a solution of the reaction product. High molecular weight polyborosiloxanes, capable of forming gel fibers, were obtained by the reaction followed by partial alkoxylation and subsequent hydrolysis. The hydrolysis of bis(ethyl acetoacetato)zirconium diethoxide was investigated to obtain polyzirconoxanes as a precursor for the oxide materials. The product was found to be a low molecular weight polymer formed by condensation of the partial hydrolysis product which showed good spinnability and gave gel fibers.

Synthesis and properties of N-alkylbromoperylene-3,4-dicarboximides

Abstract N-Alkyl-9-bromoperylene-3,4-dicarboximides (alkyl = methyl, ethyl, propyl, butyl, hexyl and octyl) were prepared by the bromination of the corresponding N-alkyl-3,4-perylenedicarboximides with bromine; the properties of these pigments are described. Ullmann reaction of the bromoperylenedicarboximides (alkyl = ethyl, propyl, and butyl) with copper bronze gave the corresponding biperylene derivatives.

Hydrolytic polycondensation of vinyltrimethoxysilane and formation of vinylpolysiloxane films

AbstractHydrolytic polycondensation of vinyltrimethoxysilane (VTM) was investigated in detail to prepare vinylpolysiloxanes (VPS) having spinnability and tough gel films. VTM was hydrolyzed in various molar ratios r1 (H2O/VTM) = 0.5–1.6 (HCl/VTM = 0.105, EtOH/VTM = 1.44) at 70°C under a N2 stream with stirring at 150 rpm to give vinylpolysiloxanes with