Kiyoshi Naruchi

Preparation and properties of polyamides and polyimides from 4,4″-diamino-o-terphenyl

Abstract Polyamides and polyimides having 4,4″- o -terphenyldiyl units in the main chain were synthesized. The polyamides were prepared from 4,4″-diamino- o -terphenyl and aromatic dicarboxylic acids or aromatic dicarbonyl dichlorides. The polyimides were prepared from 4,4″-diamino- o -terphenyl and aromatic tetracarboxylic dianhydrides. Copolyamides and copolyimides were also prepared using 4,4″-diamino- o - and other diamines. The T g values of the polyamides were high (283–298°C). The polyamides were soluble in cyclohexanone and pyridine. The polyimides also possessed high T g values (298–372°C). The solubilities of the polyimides, on the other hand, were poor. The introduction of o -terphenyl units into the main chain of the polyamides led to high thermal stability as well as good solubility.

Preparation of polyamides having 2-phenyl-4,5-imidazolediyl units in the main chain

Abstract Polyamides having 2-phenyl-4,5-imidazolediyl units in the main chain were prepared from 4,4′-2-phenyl-4,5-imidazole)dibenzoic acid and aromatic diamines. Polycondensation by a direct solution method gave high-molecular-weight polymers. The polymers are highly soluble in polar solvents and show high T g (> 290°C) and T d (> 440°C) values. Films were cast from dimethylacetamide or 1-methyl-2-pyrrolidone solutions. Mechanical properties, i.e. tensile strength, elongation at break and tensile modulus, were evaluated.

Synthesis and properties of novel aromatic polyamides containing 2-methyl-4,5-oxazolediyl structure

Abstract Novel aromatic polyamides having 2-methyl-4,5-oxazolediyl units in the main chains were synthesized. The polyamides were prepared from 4,5-di(4-aminophenyl)-2-methyloxazole (DAPMO) and/or 4,4′-[4,5-(2-methyl) oxazole]dibenzoic acid (MODBA) by the direct polycondensation method. The polyamides, the inherent viscosities of which ranged from 0.64 to 1.95 dl g −1 , were obtained almost quantitatively. The polyamides indicated high thermal properties: glass transition temperatures were found in the range between 280 and 354°C, and thermal decomposition temperatures ranged from 376 to 421°C. The polyamides exhibited good solubility in many organic solvents such as m -cresol, N,N -dimethylacetamide, 1-methyl-2-pyrrolidone, N,N -dimethyl formamide and conc. H 2 SO 4 at 2.0% (w/v). All the polyamides showed amorphous nature. The introduction of the zigzag, rigid and polar 2-methyl-4,5-oxazolediyl structure into the main chains of polyamides was effective in improving the solubility without lowering the high thermal properties.

Tetramer formation from methacrylic acid metal salts in solid state

Abstract We have investigated the formation of tetramers of methacrylic acid via the thermal reaction of metallic salts of methacrylic acid salts in the solid state in the temperature range 300°–350°C. N.m.r. and mass spectra and gas chromatography were used in the characterization of the tetramers formed.

Thermally initiated oligomerization of metallic salts of methacrylic acid in solid state

Abstract Thermal oligomerization of metallic salts of methacrylic acid was investigated over the temperature range 150°–240°C in the solid state. Calcium methacrylate gave α-methylene-γ, γ-dimethylglutarate(I) and α-methylene-δ-methyladipate(II) below 190°C, but I was not formed above 210°C. Above 170°C the trimer, 1-nonene-2,5,8-tricarboxylate(IV), was formed. Barium methacrylate gave both I and II above 170°C, and 4-methyl-1-octene-2,4,7-tricarboxylate(III) and IV above 190°C. Due to the oligomer crystals from calcium methacrylate were disordered, but crystals from barium methacrylate were transformed to the oligomer crystal lattice, I was formed not in the amorphous state but in the crystalline state, however, II was formed in both states. From these results the mechanism of the oligomer formation in the solid state was discussed.

Thermal polymerizations of alkali and alkaline earth 4-vinylbenzoates in bulk

Thermal polymerizations of alkali and alkaline earth 4-vinylbenzoates (4-VBAs) in bulk were investigated. The relative reactivity of the alkali salts decreases in the following order: K > Na > Li, which is in reverse order to that of alkali methacrylates. In the polymerization of K-4-VBA at 240°C, the number-average molecular weight decreases with increasing reaction time, although the yield of polymer increases. The polymerization of the K salt proceeds as long as the crystallinity of the monomeric salt is maintained, and is terminated when there is no crystalline compound in the reaction mixture left. The relative reactivity of the alkaline earth salts decreases in the following order: Mg > Ca > Sr >> Ba. The polymerization of Mg-4-VBA proceeds rapidly at 240°C in the initial stage (30 min) and then levels off, however, the appearance of the reaction mixture still remains crystalline.

Thermal cross-coupled dimerisation of alkali and alkaline earth metal salts of methacrylic–crotonic acid binary systems in this solid state

Thermal reaction of sodium and potassium salts of methacrylic–crotonic acids in the solid state selectively affords a cross-coupled dimer, dimethyl hex-1-ene-2,4-dicarboxylate.

Thermal dimerization of alkali-metal salts of crotonic acid in the solid state

The thermal reaction of sodium crotonate (Na-crotonate) in the solid state gave a nearly quantitative yield of hex-1-ene-3,4-dicarboxylate (1). Potassium crotonate (K-crotonate), on the other hand, afforded three isomeric dimers, i.e.(1), 4-methylpent-2-ene-3,5-dicarboxylate (2), and 2-methylene-3-methylbutane-1,4-dicarboxylate (3). In the case of Na-crotonate, X-ray analysis suggests the formation of a solid solution crystal during dimerization. K-Crotonate yielded predominantly (3) at the early stage of the reaction at 295 °C with formation of a solid solution crystal. At a higher temperature, i.e. 320 °C, (1) and (3) were gradually converted into (2), resulting in the decay of the crystal structure.

Thermal dimerization of alkali and alkaline earth acrylate–but-3-enoate and methacrylate–but-3-enoate binary systems in the solid state

The solid state thermal reaction of binary salts obtained from a solution of an equimolar mixture of alkali or alkaline earth salts of but-3-enoic acid and methacrylic acid (3-BA–MA), after conversion to the methyl ester, gave mainly dimethyl (E)-hex-1-ene-1,5-dicarboxylate as a novel cross-coupled dimer. The highest conversion (62.2%) to the cross-coupled dimer was obtained using the potassium salts on heating at 230 °C for 2 h. Similarly, the methyl ester of the cross-coupled dimer, dimethyl (E)-pent-1-ene-1,5-dicarboxylate, was obtained from the salts of 3-BA and acrylic acid (AA), however a small amount on an isomeric ester dimethyl (E)-pent-2-ene-1, 5-dicarboxylate was also obtained. The X-ray diffraction patterns of potassium 3-BA–MA and potassium 3-BA–AA indicate the presence of a new phase, different from that of the individual salts. The selective cross-coupled dimerization, without rearrangement of 3-BA to crotonic acid, polymerization and crosslinking, was due to the new crystal phase of the binary salts as well as to the formation of solid solution crystals between the monomeric salts and the dimeric salt.

Effectiveness of 4-Vinylphthalic Acid and 4-Vinylphthalic Anhydride on Adhesion to Dentin.

4-ビニルフタル酸 (4-VPA) と4-ビニルフタル酸無水物 (4-VPAN) を合成し, 10-3処理象牙質へのメタクリル酸メチル (MMA) -トリ-n-ブチルボラン (TBB) レジンの接着を向上させるため, 歯質接着促進モノマーとしてこれらをMMAに溶解させてその効果を検討した. 4-VPAでは接着強さは15%の時, 最高値を示し, その値は14.9MPaであった. MMAへの溶解性を向上させた4-VPANでは5.0%で13.9MPaを示し, これ以下の濃度ではほとんどその効果は観察されなかった. 4-VPANの機能性の低さは加水分解速度の遅さに基因していることがわかり, 4-VPANが加水分解されて親水性基が生まれ, 接着に有効に働くのは4-VPAであることが明らかとなった.