Koichi Yamaguchi

Asymmetric addition of thiol to diene polymer in the presence of optically active amines as catalyst

Abstract The asymmetric addition reaction of thiolacetic acid or benzylmercaptan to diene polymer (natural rubber, cis - and trans -1,4-polyisoprene, cis -1,4-polybutadiene, various styrenebutadiene copolymers and alternating acrylonitrile-butadiene copolymer) by optically active catalysts such as d -bornylamine ([α] d −45.2°), l -aspartic diethyl ester (−11.2°), l -aspartic dibutyl ester (−5.3°) were carried out in benzene at room temperature to 90°C. The optically active polymers were obtained from natural rubber and cis -1,4- and trans -1,4-polyisoprene, but were not obtained from cis -1,4-polybutadiene, styrene-butadiene copolymers, and butadiene-acrylonitrile copolymer. The [ α ] 25 D value of optically active derivatives was −0.1° ∼ −1.0° (in benzene), and the optical rotatory dispersion curves were found to fit the simple Drude equation.

Reaction of thiol to diene polymer in the presence of various catalysts

Abstract The addition reaction of benzylmercaptan to diene polymer (natural rubber, and cis -1,4-polyisoprene) by various optically active catalysts such as d -camphorsulphonic acid, d -percamphoric acid, and active-amylalcoholate (sodium and barium) were carried out in benzene or anisole at room temperature to 100°C. The optically active adduct polymer was only obtained from the reaction of benzylmercaptan to natural rubber and cis -1,4-polyisoprene by active-amylalcoholate (barium), but was not obtained by the other catalysts. The [ α ] 25 value of optically active adduct polymer was −0·1°C∼−0·6°C (in benzene), and the optical rotatory dispersion curves were found to fit the simple Drude equation. The reaction of benzylmercaptan to cis -1,4-polybutadiene, various styrene-butadiene copolymers, and alternating butadiene-acrylonitrile copolymer were carried out, but the optically active adduct polymers were not obtained by these catalysts.

Vinyl polymerization initiated with alkali metal adducts of triphenylamine and triphenylphosphine

Abstract The polymerizations of styrene, methyl methacrylate, isoprene, butadiene and acrylonitrile initiated with alkali metal adducts of triphenylamine or triphenylphosphine at 0°C in tetrahydrofuran take place by an anionic mechanism. Biphenyl alkali metal anion radical and alkali metal adducts of benzene, aniline and diphenylamine are formed in the reaction of triphenylamine with the alkali metal and it was shown that styrene was polymerized with both the anion radical and alkali metal adducts of benzene, whereas methyl methacrylate and acrylonitrile were polymerized by all anion species.

ADHESIVES BASED BLOCK COPOLYMER (III)

メタクリル酸メチルでグラフト重合改質したスチレン-ブタジエンブロック共重合体(以下, SBS-g-MMAという.)エマルジョンに各種粘着付与剤を添加し, 接着剤への応用について検討した. 粘着付与剤としては, ブタジエン相あるいはステレンとブタジエンの両相に相溶するものが有効であった. 粘着付与剤はエマルジョン化する前の重合溶液に, SBS-g-MMAの約10wt%添加し, エマルジョン化したものが, 高いはく離強さ及び皮膜物性を示した. 常温はり合わせ可能時間は, 粘着付与剤の添加により長くなった. 綿布と軟質ポリ塩化ビニルの接着では60°C, 7日間のエージングで, はく離強さの保持率は約60%であった. SBS-g-MMAエマルジョンへの市販ラテックスのブレンドによって, SBS-g-MMAエマルジョンの造膜性を改良し, 一方, SBS-g-MMAエマルジョンは, 市販ラテックスの改質材としても有効であることが明らかになった.